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2026-03-05xdp: produce a warning when calculated tailroom is negativeLarysa Zaremba
Many ethernet drivers report xdp Rx queue frag size as being the same as DMA write size. However, the only user of this field, namely bpf_xdp_frags_increase_tail(), clearly expects a truesize. Such difference leads to unspecific memory corruption issues under certain circumstances, e.g. in ixgbevf maximum DMA write size is 3 KB, so when running xskxceiver's XDP_ADJUST_TAIL_GROW_MULTI_BUFF, 6K packet fully uses all DMA-writable space in 2 buffers. This would be fine, if only rxq->frag_size was properly set to 4K, but value of 3K results in a negative tailroom, because there is a non-zero page offset. We are supposed to return -EINVAL and be done with it in such case, but due to tailroom being stored as an unsigned int, it is reported to be somewhere near UINT_MAX, resulting in a tail being grown, even if the requested offset is too much (it is around 2K in the abovementioned test). This later leads to all kinds of unspecific calltraces. [ 7340.337579] xskxceiver[1440]: segfault at 1da718 ip 00007f4161aeac9d sp 00007f41615a6a00 error 6 [ 7340.338040] xskxceiver[1441]: segfault at 7f410000000b ip 00000000004042b5 sp 00007f415bffecf0 error 4 [ 7340.338179] in libc.so.6[61c9d,7f4161aaf000+160000] [ 7340.339230] in xskxceiver[42b5,400000+69000] [ 7340.340300] likely on CPU 6 (core 0, socket 6) [ 7340.340302] Code: ff ff 01 e9 f4 fe ff ff 0f 1f 44 00 00 4c 39 f0 74 73 31 c0 ba 01 00 00 00 f0 0f b1 17 0f 85 ba 00 00 00 49 8b 87 88 00 00 00 <4c> 89 70 08 eb cc 0f 1f 44 00 00 48 8d bd f0 fe ff ff 89 85 ec fe [ 7340.340888] likely on CPU 3 (core 0, socket 3) [ 7340.345088] Code: 00 00 00 ba 00 00 00 00 be 00 00 00 00 89 c7 e8 31 ca ff ff 89 45 ec 8b 45 ec 85 c0 78 07 b8 00 00 00 00 eb 46 e8 0b c8 ff ff <8b> 00 83 f8 69 74 24 e8 ff c7 ff ff 8b 00 83 f8 0b 74 18 e8 f3 c7 [ 7340.404334] Oops: general protection fault, probably for non-canonical address 0x6d255010bdffc: 0000 [#1] SMP NOPTI [ 7340.405972] CPU: 7 UID: 0 PID: 1439 Comm: xskxceiver Not tainted 6.19.0-rc1+ #21 PREEMPT(lazy) [ 7340.408006] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.17.0-5.fc42 04/01/2014 [ 7340.409716] RIP: 0010:lookup_swap_cgroup_id+0x44/0x80 [ 7340.410455] Code: 83 f8 1c 73 39 48 ba ff ff ff ff ff ff ff 03 48 8b 04 c5 20 55 fa bd 48 21 d1 48 89 ca 83 e1 01 48 d1 ea c1 e1 04 48 8d 04 90 <8b> 00 48 83 c4 10 d3 e8 c3 cc cc cc cc 31 c0 e9 98 b7 dd 00 48 89 [ 7340.412787] RSP: 0018:ffffcc5c04f7f6d0 EFLAGS: 00010202 [ 7340.413494] RAX: 0006d255010bdffc RBX: ffff891f477895a8 RCX: 0000000000000010 [ 7340.414431] RDX: 0001c17e3fffffff RSI: 00fa070000000000 RDI: 000382fc7fffffff [ 7340.415354] RBP: 00fa070000000000 R08: ffffcc5c04f7f8f8 R09: ffffcc5c04f7f7d0 [ 7340.416283] R10: ffff891f4c1a7000 R11: ffffcc5c04f7f9c8 R12: ffffcc5c04f7f7d0 [ 7340.417218] R13: 03ffffffffffffff R14: 00fa06fffffffe00 R15: ffff891f47789500 [ 7340.418229] FS: 0000000000000000(0000) GS:ffff891ffdfaa000(0000) knlGS:0000000000000000 [ 7340.419489] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 7340.420286] CR2: 00007f415bfffd58 CR3: 0000000103f03002 CR4: 0000000000772ef0 [ 7340.421237] PKRU: 55555554 [ 7340.421623] Call Trace: [ 7340.421987] <TASK> [ 7340.422309] ? softleaf_from_pte+0x77/0xa0 [ 7340.422855] swap_pte_batch+0xa7/0x290 [ 7340.423363] zap_nonpresent_ptes.constprop.0.isra.0+0xd1/0x270 [ 7340.424102] zap_pte_range+0x281/0x580 [ 7340.424607] zap_pmd_range.isra.0+0xc9/0x240 [ 7340.425177] unmap_page_range+0x24d/0x420 [ 7340.425714] unmap_vmas+0xa1/0x180 [ 7340.426185] exit_mmap+0xe1/0x3b0 [ 7340.426644] __mmput+0x41/0x150 [ 7340.427098] exit_mm+0xb1/0x110 [ 7340.427539] do_exit+0x1b2/0x460 [ 7340.427992] do_group_exit+0x2d/0xc0 [ 7340.428477] get_signal+0x79d/0x7e0 [ 7340.428957] arch_do_signal_or_restart+0x34/0x100 [ 7340.429571] exit_to_user_mode_loop+0x8e/0x4c0 [ 7340.430159] do_syscall_64+0x188/0x6b0 [ 7340.430672] ? __do_sys_clone3+0xd9/0x120 [ 7340.431212] ? switch_fpu_return+0x4e/0xd0 [ 7340.431761] ? arch_exit_to_user_mode_prepare.isra.0+0xa1/0xc0 [ 7340.432498] ? do_syscall_64+0xbb/0x6b0 [ 7340.433015] ? __handle_mm_fault+0x445/0x690 [ 7340.433582] ? count_memcg_events+0xd6/0x210 [ 7340.434151] ? handle_mm_fault+0x212/0x340 [ 7340.434697] ? do_user_addr_fault+0x2b4/0x7b0 [ 7340.435271] ? clear_bhb_loop+0x30/0x80 [ 7340.435788] ? clear_bhb_loop+0x30/0x80 [ 7340.436299] ? clear_bhb_loop+0x30/0x80 [ 7340.436812] ? clear_bhb_loop+0x30/0x80 [ 7340.437323] entry_SYSCALL_64_after_hwframe+0x76/0x7e [ 7340.437973] RIP: 0033:0x7f4161b14169 [ 7340.438468] Code: Unable to access opcode bytes at 0x7f4161b1413f. [ 7340.439242] RSP: 002b:00007ffc6ebfa770 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca [ 7340.440173] RAX: fffffffffffffe00 RBX: 00000000000005a1 RCX: 00007f4161b14169 [ 7340.441061] RDX: 00000000000005a1 RSI: 0000000000000109 RDI: 00007f415bfff990 [ 7340.441943] RBP: 00007ffc6ebfa7a0 R08: 0000000000000000 R09: 00000000ffffffff [ 7340.442824] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 [ 7340.443707] R13: 0000000000000000 R14: 00007f415bfff990 R15: 00007f415bfff6c0 [ 7340.444586] </TASK> [ 7340.444922] Modules linked in: rfkill intel_rapl_msr intel_rapl_common intel_uncore_frequency_common skx_edac_common nfit libnvdimm kvm_intel vfat fat kvm snd_pcm irqbypass rapl iTCO_wdt snd_timer intel_pmc_bxt iTCO_vendor_support snd ixgbevf virtio_net soundcore i2c_i801 pcspkr libeth_xdp net_failover i2c_smbus lpc_ich failover libeth virtio_balloon joydev 9p fuse loop zram lz4hc_compress lz4_compress 9pnet_virtio 9pnet netfs ghash_clmulni_intel serio_raw qemu_fw_cfg [ 7340.449650] ---[ end trace 0000000000000000 ]--- The issue can be fixed in all in-tree drivers, but we cannot just trust OOT drivers to not do this. Therefore, make tailroom a signed int and produce a warning when it is negative to prevent such mistakes in the future. Fixes: bf25146a5595 ("bpf: add frags support to the bpf_xdp_adjust_tail() API") Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov@intel.com> Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com> Acked-by: Martin KaFai Lau <martin.lau@kernel.org> Signed-off-by: Larysa Zaremba <larysa.zaremba@intel.com> Link: https://patch.msgid.link/20260305111253.2317394-10-larysa.zaremba@intel.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-03-05xdp: use modulo operation to calculate XDP frag tailroomLarysa Zaremba
The current formula for calculating XDP tailroom in mbuf packets works only if each frag has its own page (if rxq->frag_size is PAGE_SIZE), this defeats the purpose of the parameter overall and without any indication leads to negative calculated tailroom on at least half of frags, if shared pages are used. There are not many drivers that set rxq->frag_size. Among them: * i40e and enetc always split page uniformly between frags, use shared pages * ice uses page_pool frags via libeth, those are power-of-2 and uniformly distributed across page * idpf has variable frag_size with XDP on, so current API is not applicable * mlx5, mtk and mvneta use PAGE_SIZE or 0 as frag_size for page_pool As for AF_XDP ZC, only ice, i40e and idpf declare frag_size for it. Modulo operation yields good results for aligned chunks, they are all power-of-2, between 2K and PAGE_SIZE. Formula without modulo fails when chunk_size is 2K. Buffers in unaligned mode are not distributed uniformly, so modulo operation would not work. To accommodate unaligned buffers, we could define frag_size as data + tailroom, and hence do not subtract offset when calculating tailroom, but this would necessitate more changes in the drivers. Define rxq->frag_size as an even portion of a page that fully belongs to a single frag. When calculating tailroom, locate the data start within such portion by performing a modulo operation on page offset. Fixes: bf25146a5595 ("bpf: add frags support to the bpf_xdp_adjust_tail() API") Acked-by: Jakub Kicinski <kuba@kernel.org> Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov@intel.com> Signed-off-by: Larysa Zaremba <larysa.zaremba@intel.com> Link: https://patch.msgid.link/20260305111253.2317394-2-larysa.zaremba@intel.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-03-05net/sched: act_ife: Fix metalist update behaviorJamal Hadi Salim
Whenever an ife action replace changes the metalist, instead of replacing the old data on the metalist, the current ife code is appending the new metadata. Aside from being innapropriate behavior, this may lead to an unbounded addition of metadata to the metalist which might cause an out of bounds error when running the encode op: [ 138.423369][ C1] ================================================================== [ 138.424317][ C1] BUG: KASAN: slab-out-of-bounds in ife_tlv_meta_encode (net/ife/ife.c:168) [ 138.424906][ C1] Write of size 4 at addr ffff8880077f4ffe by task ife_out_out_bou/255 [ 138.425778][ C1] CPU: 1 UID: 0 PID: 255 Comm: ife_out_out_bou Not tainted 7.0.0-rc1-00169-gfbdfa8da05b6 #624 PREEMPT(full) [ 138.425795][ C1] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 [ 138.425800][ C1] Call Trace: [ 138.425804][ C1] <IRQ> [ 138.425808][ C1] dump_stack_lvl (lib/dump_stack.c:122) [ 138.425828][ C1] print_report (mm/kasan/report.c:379 mm/kasan/report.c:482) [ 138.425839][ C1] ? srso_alias_return_thunk (arch/x86/lib/retpoline.S:221) [ 138.425844][ C1] ? __virt_addr_valid (./arch/x86/include/asm/preempt.h:95 (discriminator 1) ./include/linux/rcupdate.h:975 (discriminator 1) ./include/linux/mmzone.h:2207 (discriminator 1) arch/x86/mm/physaddr.c:54 (discriminator 1)) [ 138.425853][ C1] ? ife_tlv_meta_encode (net/ife/ife.c:168) [ 138.425859][ C1] kasan_report (mm/kasan/report.c:221 mm/kasan/report.c:597) [ 138.425868][ C1] ? ife_tlv_meta_encode (net/ife/ife.c:168) [ 138.425878][ C1] kasan_check_range (mm/kasan/generic.c:186 (discriminator 1) mm/kasan/generic.c:200 (discriminator 1)) [ 138.425884][ C1] __asan_memset (mm/kasan/shadow.c:84 (discriminator 2)) [ 138.425889][ C1] ife_tlv_meta_encode (net/ife/ife.c:168) [ 138.425893][ C1] ? ife_tlv_meta_encode (net/ife/ife.c:171) [ 138.425898][ C1] ? srso_alias_return_thunk (arch/x86/lib/retpoline.S:221) [ 138.425903][ C1] ife_encode_meta_u16 (net/sched/act_ife.c:57) [ 138.425910][ C1] ? __pfx_do_raw_spin_lock (kernel/locking/spinlock_debug.c:114) [ 138.425916][ C1] ? __asan_memcpy (mm/kasan/shadow.c:105 (discriminator 3)) [ 138.425921][ C1] ? __pfx_ife_encode_meta_u16 (net/sched/act_ife.c:45) [ 138.425927][ C1] ? srso_alias_return_thunk (arch/x86/lib/retpoline.S:221) [ 138.425931][ C1] tcf_ife_act (net/sched/act_ife.c:847 net/sched/act_ife.c:879) To solve this issue, fix the replace behavior by adding the metalist to the ife rcu data structure. Fixes: aa9fd9a325d51 ("sched: act: ife: update parameters via rcu handling") Reported-by: Ruitong Liu <cnitlrt@gmail.com> Tested-by: Ruitong Liu <cnitlrt@gmail.com> Co-developed-by: Victor Nogueira <victor@mojatatu.com> Signed-off-by: Victor Nogueira <victor@mojatatu.com> Signed-off-by: Jamal Hadi Salim <jhs@mojatatu.com> Link: https://patch.msgid.link/20260304140603.76500-1-jhs@mojatatu.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-03-05net: ipv6: fix panic when IPv4 route references loopback IPv6 nexthopJiayuan Chen
When a standalone IPv6 nexthop object is created with a loopback device (e.g., "ip -6 nexthop add id 100 dev lo"), fib6_nh_init() misclassifies it as a reject route. This is because nexthop objects have no destination prefix (fc_dst=::), causing fib6_is_reject() to match any loopback nexthop. The reject path skips fib_nh_common_init(), leaving nhc_pcpu_rth_output unallocated. If an IPv4 route later references this nexthop, __mkroute_output() dereferences NULL nhc_pcpu_rth_output and panics. Simplify the check in fib6_nh_init() to only match explicit reject routes (RTF_REJECT) instead of using fib6_is_reject(). The loopback promotion heuristic in fib6_is_reject() is handled separately by ip6_route_info_create_nh(). After this change, the three cases behave as follows: 1. Explicit reject route ("ip -6 route add unreachable 2001:db8::/64"): RTF_REJECT is set, enters reject path, skips fib_nh_common_init(). No behavior change. 2. Implicit loopback reject route ("ip -6 route add 2001:db8::/32 dev lo"): RTF_REJECT is not set, takes normal path, fib_nh_common_init() is called. ip6_route_info_create_nh() still promotes it to reject afterward. nhc_pcpu_rth_output is allocated but unused, which is harmless. 3. Standalone nexthop object ("ip -6 nexthop add id 100 dev lo"): RTF_REJECT is not set, takes normal path, fib_nh_common_init() is called. nhc_pcpu_rth_output is properly allocated, fixing the crash when IPv4 routes reference this nexthop. Suggested-by: Ido Schimmel <idosch@nvidia.com> Fixes: 493ced1ac47c ("ipv4: Allow routes to use nexthop objects") Reported-by: syzbot+334190e097a98a1b81bb@syzkaller.appspotmail.com Closes: https://lore.kernel.org/all/698f8482.a70a0220.2c38d7.00ca.GAE@google.com/T/ Signed-off-by: Jiayuan Chen <jiayuan.chen@shopee.com> Reviewed-by: Ido Schimmel <idosch@nvidia.com> Reviewed-by: David Ahern <dsahern@kernel.org> Link: https://patch.msgid.link/20260304113817.294966-2-jiayuan.chen@linux.dev Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-03-05net: bridge: fix nd_tbl NULL dereference when IPv6 is disabledFernando Fernandez Mancera
When booting with the 'ipv6.disable=1' parameter, the nd_tbl is never initialized because inet6_init() exits before ndisc_init() is called which initializes it. Then, if neigh_suppress is enabled and an ICMPv6 Neighbor Discovery packet reaches the bridge, br_do_suppress_nd() will dereference ipv6_stub->nd_tbl which is NULL, passing it to neigh_lookup(). This causes a kernel NULL pointer dereference. BUG: kernel NULL pointer dereference, address: 0000000000000268 Oops: 0000 [#1] PREEMPT SMP NOPTI [...] RIP: 0010:neigh_lookup+0x16/0xe0 [...] Call Trace: <IRQ> ? neigh_lookup+0x16/0xe0 br_do_suppress_nd+0x160/0x290 [bridge] br_handle_frame_finish+0x500/0x620 [bridge] br_handle_frame+0x353/0x440 [bridge] __netif_receive_skb_core.constprop.0+0x298/0x1110 __netif_receive_skb_one_core+0x3d/0xa0 process_backlog+0xa0/0x140 __napi_poll+0x2c/0x170 net_rx_action+0x2c4/0x3a0 handle_softirqs+0xd0/0x270 do_softirq+0x3f/0x60 Fix this by replacing IS_ENABLED(IPV6) call with ipv6_mod_enabled() in the callers. This is in essence disabling NS/NA suppression when IPv6 is disabled. Fixes: ed842faeb2bd ("bridge: suppress nd pkts on BR_NEIGH_SUPPRESS ports") Reported-by: Guruprasad C P <gurucp2005@gmail.com> Closes: https://lore.kernel.org/netdev/CAHXs0ORzd62QOG-Fttqa2Cx_A_VFp=utE2H2VTX5nqfgs7LDxQ@mail.gmail.com/ Signed-off-by: Fernando Fernandez Mancera <fmancera@suse.de> Reviewed-by: Ido Schimmel <idosch@nvidia.com> Acked-by: Nikolay Aleksandrov <razor@blackwall.org> Link: https://patch.msgid.link/20260304120357.9778-1-fmancera@suse.de Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-03-05netfilter: nft_set_pipapo: split gc into unlink and reclaim phaseFlorian Westphal
Yiming Qian reports Use-after-free in the pipapo set type: Under a large number of expired elements, commit-time GC can run for a very long time in a non-preemptible context, triggering soft lockup warnings and RCU stall reports (local denial of service). We must split GC in an unlink and a reclaim phase. We cannot queue elements for freeing until pointers have been swapped. Expired elements are still exposed to both the packet path and userspace dumpers via the live copy of the data structure. call_rcu() does not protect us: dump operations or element lookups starting after call_rcu has fired can still observe the free'd element, unless the commit phase has made enough progress to swap the clone and live pointers before any new reader has picked up the old version. This a similar approach as done recently for the rbtree backend in commit 35f83a75529a ("netfilter: nft_set_rbtree: don't gc elements on insert"). Fixes: 3c4287f62044 ("nf_tables: Add set type for arbitrary concatenation of ranges") Reported-by: Yiming Qian <yimingqian591@gmail.com> Signed-off-by: Florian Westphal <fw@strlen.de>
2026-03-05netfilter: nf_tables: clone set on flush onlyPablo Neira Ayuso
Syzbot with fault injection triggered a failing memory allocation with GFP_KERNEL which results in a WARN splat: iter.err WARNING: net/netfilter/nf_tables_api.c:845 at nft_map_deactivate+0x34e/0x3c0 net/netfilter/nf_tables_api.c:845, CPU#0: syz.0.17/5992 Modules linked in: CPU: 0 UID: 0 PID: 5992 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 RIP: 0010:nft_map_deactivate+0x34e/0x3c0 net/netfilter/nf_tables_api.c:845 Code: 8b 05 86 5a 4e 09 48 3b 84 24 a0 00 00 00 75 62 48 8d 65 d8 5b 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc cc e8 63 6d fa f7 90 <0f> 0b 90 43 +80 7c 35 00 00 0f 85 23 fe ff ff e9 26 fe ff ff 89 d9 RSP: 0018:ffffc900045af780 EFLAGS: 00010293 RAX: ffffffff89ca45bd RBX: 00000000fffffff4 RCX: ffff888028111e40 RDX: 0000000000000000 RSI: 00000000fffffff4 RDI: 0000000000000000 RBP: ffffc900045af870 R08: 0000000000400dc0 R09: 00000000ffffffff R10: dffffc0000000000 R11: fffffbfff1d141db R12: ffffc900045af7e0 R13: 1ffff920008b5f24 R14: dffffc0000000000 R15: ffffc900045af920 FS: 000055557a6a5500(0000) GS:ffff888125496000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fb5ea271fc0 CR3: 000000003269e000 CR4: 00000000003526f0 Call Trace: <TASK> __nft_release_table+0xceb/0x11f0 net/netfilter/nf_tables_api.c:12115 nft_rcv_nl_event+0xc25/0xdb0 net/netfilter/nf_tables_api.c:12187 notifier_call_chain+0x19d/0x3a0 kernel/notifier.c:85 blocking_notifier_call_chain+0x6a/0x90 kernel/notifier.c:380 netlink_release+0x123b/0x1ad0 net/netlink/af_netlink.c:761 __sock_release net/socket.c:662 [inline] sock_close+0xc3/0x240 net/socket.c:1455 Restrict set clone to the flush set command in the preparation phase. Add NFT_ITER_UPDATE_CLONE and use it for this purpose, update the rbtree and pipapo backends to only clone the set when this iteration type is used. As for the existing NFT_ITER_UPDATE type, update the pipapo backend to use the existing set clone if available, otherwise use the existing set representation. After this update, there is no need to clone a set that is being deleted, this includes bound anonymous set. An alternative approach to NFT_ITER_UPDATE_CLONE is to add a .clone interface and call it from the flush set path. Reported-by: syzbot+4924a0edc148e8b4b342@syzkaller.appspotmail.com Fixes: 3f1d886cc7c3 ("netfilter: nft_set_pipapo: move cloning of match info to insert/removal path") Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: Florian Westphal <fw@strlen.de>
2026-03-05netfilter: nf_tables: unconditionally bump set->nelems before insertionPablo Neira Ayuso
In case that the set is full, a new element gets published then removed without waiting for the RCU grace period, while RCU reader can be walking over it already. To address this issue, add the element transaction even if set is full, but toggle the set_full flag to report -ENFILE so the abort path safely unwinds the set to its previous state. As for element updates, decrement set->nelems to restore it. A simpler fix is to call synchronize_rcu() in the error path. However, with a large batch adding elements to already maxed-out set, this could cause noticeable slowdown of such batches. Fixes: 35d0ac9070ef ("netfilter: nf_tables: fix set->nelems counting with no NLM_F_EXCL") Reported-by: Inseo An <y0un9sa@gmail.com> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: Florian Westphal <fw@strlen.de>
2026-03-05net: Provide a PREEMPT_RT specific check for netdev_queue::_xmit_lockSebastian Andrzej Siewior
After acquiring netdev_queue::_xmit_lock the number of the CPU owning the lock is recorded in netdev_queue::xmit_lock_owner. This works as long as the BH context is not preemptible. On PREEMPT_RT the softirq context is preemptible and without the softirq-lock it is possible to have multiple user in __dev_queue_xmit() submitting a skb on the same CPU. This is fine in general but this means also that the current CPU is recorded as netdev_queue::xmit_lock_owner. This in turn leads to the recursion alert and the skb is dropped. Instead checking the for CPU number, that owns the lock, PREEMPT_RT can check if the lockowner matches the current task. Add netif_tx_owned() which returns true if the current context owns the lock by comparing the provided CPU number with the recorded number. This resembles the current check by negating the condition (the current check returns true if the lock is not owned). On PREEMPT_RT use rt_mutex_owner() to return the lock owner and compare the current task against it. Use the new helper in __dev_queue_xmit() and netif_local_xmit_active() which provides a similar check. Update comments regarding pairing READ_ONCE(). Reported-by: Bert Karwatzki <spasswolf@web.de> Closes: https://lore.kernel.org/all/20260216134333.412332-1-spasswolf@web.de Fixes: 3253cb49cbad4 ("softirq: Allow to drop the softirq-BKL lock on PREEMPT_RT") Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Reported-by: Bert Karwatzki <spasswolf@web.de> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Link: https://patch.msgid.link/20260302162631.uGUyIqDT@linutronix.de Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2026-03-04mptcp: pm: in-kernel: always mark signal+subflow endp as usedMatthieu Baerts (NGI0)
Syzkaller managed to find a combination of actions that was generating this warning: msk->pm.local_addr_used == 0 WARNING: net/mptcp/pm_kernel.c:1071 at __mark_subflow_endp_available net/mptcp/pm_kernel.c:1071 [inline], CPU#1: syz.2.17/961 WARNING: net/mptcp/pm_kernel.c:1071 at mptcp_nl_remove_subflow_and_signal_addr net/mptcp/pm_kernel.c:1103 [inline], CPU#1: syz.2.17/961 WARNING: net/mptcp/pm_kernel.c:1071 at mptcp_pm_nl_del_addr_doit+0x81d/0x8f0 net/mptcp/pm_kernel.c:1210, CPU#1: syz.2.17/961 Modules linked in: CPU: 1 UID: 0 PID: 961 Comm: syz.2.17 Not tainted 6.19.0-08368-gfafda3b4b06b #22 PREEMPT(full) Hardware name: QEMU Ubuntu 25.10 PC v2 (i440FX + PIIX, + 10.1 machine, 1996), BIOS 1.17.0-debian-1.17.0-1build1 04/01/2014 RIP: 0010:__mark_subflow_endp_available net/mptcp/pm_kernel.c:1071 [inline] RIP: 0010:mptcp_nl_remove_subflow_and_signal_addr net/mptcp/pm_kernel.c:1103 [inline] RIP: 0010:mptcp_pm_nl_del_addr_doit+0x81d/0x8f0 net/mptcp/pm_kernel.c:1210 Code: 89 c5 e8 46 30 6f fe e9 21 fd ff ff 49 83 ed 80 e8 38 30 6f fe 4c 89 ef be 03 00 00 00 e8 db 49 df fe eb ac e8 24 30 6f fe 90 <0f> 0b 90 e9 1d ff ff ff e8 16 30 6f fe eb 05 e8 0f 30 6f fe e8 9a RSP: 0018:ffffc90001663880 EFLAGS: 00010293 RAX: ffffffff82de1a6c RBX: 0000000000000000 RCX: ffff88800722b500 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffff8880158b22d0 R08: 0000000000010425 R09: ffffffffffffffff R10: ffffffff82de18ba R11: 0000000000000000 R12: ffff88800641a640 R13: ffff8880158b1880 R14: ffff88801ec3c900 R15: ffff88800641a650 FS: 00005555722c3500(0000) GS:ffff8880f909d000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f66346e0f60 CR3: 000000001607c000 CR4: 0000000000350ef0 Call Trace: <TASK> genl_family_rcv_msg_doit+0x117/0x180 net/netlink/genetlink.c:1115 genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline] genl_rcv_msg+0x3a8/0x3f0 net/netlink/genetlink.c:1210 netlink_rcv_skb+0x16d/0x240 net/netlink/af_netlink.c:2550 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x3e9/0x4c0 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x4aa/0x5b0 net/netlink/af_netlink.c:1894 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg+0xc9/0xf0 net/socket.c:742 ____sys_sendmsg+0x272/0x3b0 net/socket.c:2592 ___sys_sendmsg+0x2de/0x320 net/socket.c:2646 __sys_sendmsg net/socket.c:2678 [inline] __do_sys_sendmsg net/socket.c:2683 [inline] __se_sys_sendmsg net/socket.c:2681 [inline] __x64_sys_sendmsg+0x110/0x1a0 net/socket.c:2681 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x143/0x440 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f66346f826d Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffc83d8bdc8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f6634985fa0 RCX: 00007f66346f826d RDX: 00000000040000b0 RSI: 0000200000000740 RDI: 0000000000000007 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f6634985fa8 R13: 00007f6634985fac R14: 0000000000000000 R15: 0000000000001770 </TASK> The actions that caused that seem to be: - Set the MPTCP subflows limit to 0 - Create an MPTCP endpoint with both the 'signal' and 'subflow' flags - Create a new MPTCP connection from a different address: an ADD_ADDR linked to the MPTCP endpoint will be sent ('signal' flag), but no subflows is initiated ('subflow' flag) - Remove the MPTCP endpoint In this case, msk->pm.local_addr_used has been kept to 0 -- because no subflows have been created -- but the corresponding bit in msk->pm.id_avail_bitmap has been cleared when the ADD_ADDR has been sent. This later causes a splat when removing the MPTCP endpoint because msk->pm.local_addr_used has been kept to 0. Now, if an endpoint has both the signal and subflow flags, but it is not possible to create subflows because of the limits or the c-flag case, then the local endpoint counter is still incremented: the endpoint is used at the end. This avoids issues later when removing the endpoint and calling __mark_subflow_endp_available(), which expects msk->pm.local_addr_used to have been previously incremented if the endpoint was marked as used according to msk->pm.id_avail_bitmap. Note that signal_and_subflow variable is reset to false when the limits and the c-flag case allows subflows creation. Also, local_addr_used is only incremented for non ID0 subflows. Fixes: 85df533a787b ("mptcp: pm: do not ignore 'subflow' if 'signal' flag is also set") Cc: stable@vger.kernel.org Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/613 Reviewed-by: Mat Martineau <martineau@kernel.org> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Link: https://patch.msgid.link/20260303-net-mptcp-misc-fixes-7-0-rc2-v1-4-4b5462b6f016@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-03-04mptcp: pm: avoid sending RM_ADDR over same subflowMatthieu Baerts (NGI0)
RM_ADDR are sent over an active subflow, the first one in the subflows list. There is then a high chance the initial subflow is picked. With the in-kernel PM, when an endpoint is removed, a RM_ADDR is sent, then linked subflows are closed. This is done for each active MPTCP connection. MPTCP endpoints are likely removed because the attached network is no longer available or usable. In this case, it is better to avoid sending this RM_ADDR over the subflow that is going to be removed, but prefer sending it over another active and non stale subflow, if any. This modification avoids situations where the other end is not notified when a subflow is no longer usable: typically when the endpoint linked to the initial subflow is removed, especially on the server side. Fixes: 8dd5efb1f91b ("mptcp: send ack for rm_addr") Cc: stable@vger.kernel.org Reported-by: Frank Lorenz <lorenz-frank@web.de> Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/612 Reviewed-by: Mat Martineau <martineau@kernel.org> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Link: https://patch.msgid.link/20260303-net-mptcp-misc-fixes-7-0-rc2-v1-2-4b5462b6f016@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-03-04nfc: rawsock: cancel tx_work before socket teardownJakub Kicinski
In rawsock_release(), cancel any pending tx_work and purge the write queue before orphaning the socket. rawsock_tx_work runs on the system workqueue and calls nfc_data_exchange which dereferences the NCI device. Without synchronization, tx_work can race with socket and device teardown when a process is killed (e.g. by SIGKILL), leading to use-after-free or leaked references. Set SEND_SHUTDOWN first so that if tx_work is already running it will see the flag and skip transmitting, then use cancel_work_sync to wait for any in-progress execution to finish, and finally purge any remaining queued skbs. Fixes: 23b7869c0fd0 ("NFC: add the NFC socket raw protocol") Reviewed-by: Joe Damato <joe@dama.to> Link: https://patch.msgid.link/20260303162346.2071888-6-kuba@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-03-04nfc: nci: clear NCI_DATA_EXCHANGE before calling completion callbackJakub Kicinski
Move clear_bit(NCI_DATA_EXCHANGE) before invoking the data exchange callback in nci_data_exchange_complete(). The callback (e.g. rawsock_data_exchange_complete) may immediately schedule another data exchange via schedule_work(tx_work). On a multi-CPU system, tx_work can run and reach nci_transceive() before the current nci_data_exchange_complete() clears the flag, causing test_and_set_bit(NCI_DATA_EXCHANGE) to return -EBUSY and the new transfer to fail. This causes intermittent flakes in nci/nci_dev in NIPA: # # RUN NCI.NCI1_0.t4t_tag_read ... # # t4t_tag_read: Test terminated by timeout # # FAIL NCI.NCI1_0.t4t_tag_read # not ok 3 NCI.NCI1_0.t4t_tag_read Fixes: 38f04c6b1b68 ("NFC: protect nci_data_exchange transactions") Reviewed-by: Joe Damato <joe@dama.to> Link: https://patch.msgid.link/20260303162346.2071888-5-kuba@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-03-04nfc: nci: complete pending data exchange on device closeJakub Kicinski
In nci_close_device(), complete any pending data exchange before closing. The data exchange callback (e.g. rawsock_data_exchange_complete) holds a socket reference. NIPA occasionally hits this leak: unreferenced object 0xff1100000f435000 (size 2048): comm "nci_dev", pid 3954, jiffies 4295441245 hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 27 00 01 40 00 00 00 00 00 00 00 00 00 00 00 00 '..@............ backtrace (crc ec2b3c5): __kmalloc_noprof+0x4db/0x730 sk_prot_alloc.isra.0+0xe4/0x1d0 sk_alloc+0x36/0x760 rawsock_create+0xd1/0x540 nfc_sock_create+0x11f/0x280 __sock_create+0x22d/0x630 __sys_socket+0x115/0x1d0 __x64_sys_socket+0x72/0xd0 do_syscall_64+0x117/0xfc0 entry_SYSCALL_64_after_hwframe+0x4b/0x53 Fixes: 38f04c6b1b68 ("NFC: protect nci_data_exchange transactions") Reviewed-by: Joe Damato <joe@dama.to> Link: https://patch.msgid.link/20260303162346.2071888-4-kuba@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-03-04nfc: digital: free skb on digital_in_send error pathsJakub Kicinski
digital_in_send() takes ownership of the skb passed by the caller (nfc_data_exchange), make sure it's freed on all error paths. Found looking around the real driver for similar bugs to the one just fixed in nci. Fixes: 2c66daecc409 ("NFC Digital: Add NFC-A technology support") Reviewed-by: Joe Damato <joe@dama.to> Link: https://patch.msgid.link/20260303162346.2071888-3-kuba@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-03-04nfc: nci: free skb on nci_transceive early error pathsJakub Kicinski
nci_transceive() takes ownership of the skb passed by the caller, but the -EPROTO, -EINVAL, and -EBUSY error paths return without freeing it. Due to issues clearing NCI_DATA_EXCHANGE fixed by subsequent changes the nci/nci_dev selftest hits the error path occasionally in NIPA, and kmemleak detects leaks: unreferenced object 0xff11000015ce6a40 (size 640): comm "nci_dev", pid 3954, jiffies 4295441246 hex dump (first 32 bytes): 6b 6b 6b 6b 00 a4 00 0c 02 e1 03 6b 6b 6b 6b 6b kkkk.......kkkkk 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk backtrace (crc 7c40cc2a): kmem_cache_alloc_node_noprof+0x492/0x630 __alloc_skb+0x11e/0x5f0 alloc_skb_with_frags+0xc6/0x8f0 sock_alloc_send_pskb+0x326/0x3f0 nfc_alloc_send_skb+0x94/0x1d0 rawsock_sendmsg+0x162/0x4c0 do_syscall_64+0x117/0xfc0 Fixes: 6a2968aaf50c ("NFC: basic NCI protocol implementation") Reviewed-by: Joe Damato <joe@dama.to> Link: https://patch.msgid.link/20260303162346.2071888-2-kuba@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-03-04net: devmem: use READ_ONCE/WRITE_ONCE on binding->devBobby Eshleman
binding->dev is protected on the write-side in mp_dmabuf_devmem_uninstall() against concurrent writes, but due to the concurrent bare reads in net_devmem_get_binding() and validate_xmit_unreadable_skb() it should be wrapped in a READ_ONCE/WRITE_ONCE pair to make sure no compiler optimizations play with the underlying register in unforeseen ways. Doesn't present a critical bug because the known compiler optimizations don't result in bad behavior. There is no tearing on u64, and load omissions/invented loads would only break if additional binding->dev references were inlined together (they aren't right now). This just more strictly follows the linux memory model (i.e., "Lock-Protected Writes With Lockless Reads" in tools/memory-model/Documentation/access-marking.txt). Fixes: bd61848900bf ("net: devmem: Implement TX path") Signed-off-by: Bobby Eshleman <bobbyeshleman@meta.com> Link: https://patch.msgid.link/20260302-devmem-membar-fix-v2-1-5b33c9cbc28b@meta.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-03-04net_sched: sch_fq: clear q->band_pkt_count[] in fq_reset()Eric Dumazet
When/if a NIC resets, queues are deactivated by dev_deactivate_many(), then reactivated when the reset operation completes. fq_reset() removes all the skbs from various queues. If we do not clear q->band_pkt_count[], these counters keep growing and can eventually reach sch->limit, preventing new packets to be queued. Many thanks to Praveen for discovering the root cause. Fixes: 29f834aa326e ("net_sched: sch_fq: add 3 bands and WRR scheduling") Diagnosed-by: Praveen Kaligineedi <pkaligineedi@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Neal Cardwell <ncardwell@google.com> Reviewed-by: Willem de Bruijn <willemb@google.com> Link: https://patch.msgid.link/20260304015640.961780-1-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-03-04net: nfc: nci: Fix zero-length proprietary notificationsIan Ray
NCI NFC controllers may have proprietary OIDs with zero-length payload. One example is: drivers/nfc/nxp-nci/core.c, NXP_NCI_RF_TXLDO_ERROR_NTF. Allow a zero length payload in proprietary notifications *only*. Before: -- >8 -- kernel: nci: nci_recv_frame: len 3 -- >8 -- After: -- >8 -- kernel: nci: nci_recv_frame: len 3 kernel: nci: nci_ntf_packet: NCI RX: MT=ntf, PBF=0, GID=0x1, OID=0x23, plen=0 kernel: nci: nci_ntf_packet: unknown ntf opcode 0x123 kernel: nfc nfc0: NFC: RF transmitter couldn't start. Bad power and/or configuration? -- >8 -- After fixing the hardware: -- >8 -- kernel: nci: nci_recv_frame: len 27 kernel: nci: nci_ntf_packet: NCI RX: MT=ntf, PBF=0, GID=0x1, OID=0x5, plen=24 kernel: nci: nci_rf_intf_activated_ntf_packet: rf_discovery_id 1 -- >8 -- Fixes: d24b03535e5e ("nfc: nci: Fix uninit-value in nci_dev_up and nci_ntf_packet") Signed-off-by: Ian Ray <ian.ray@gehealthcare.com> Link: https://patch.msgid.link/20260302163238.140576-1-ian.ray@gehealthcare.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-03-04tcp: secure_seq: add back ports to TS offsetEric Dumazet
This reverts 28ee1b746f49 ("secure_seq: downgrade to per-host timestamp offsets") tcp_tw_recycle went away in 2017. Zhouyan Deng reported off-path TCP source port leakage via SYN cookie side-channel that can be fixed in multiple ways. One of them is to bring back TCP ports in TS offset randomization. As a bonus, we perform a single siphash() computation to provide both an ISN and a TS offset. Fixes: 28ee1b746f49 ("secure_seq: downgrade to per-host timestamp offsets") Reported-by: Zhouyan Deng <dengzhouyan_nwpu@163.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com> Acked-by: Florian Westphal <fw@strlen.de> Link: https://patch.msgid.link/20260302205527.1982836-1-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-03-04Merge tag 'linux-can-fixes-for-7.0-20260302' of ↵Jakub Kicinski
git://git.kernel.org/pub/scm/linux/kernel/git/mkl/linux-can Marc Kleine-Budde says: ==================== pull-request: can 2026-03-02 The first 2 patches are by Oliver Hartkopp. The first fixes the locking for CAN Broadcast Manager op runtime updates, the second fixes the packet statisctics for the CAN dummy driver. Alban Bedel's patch fixes a potential problem in the error path of the mcp251x's ndo_open callback. A patch by Ziyi Guo add USB endpoint type validation to the esd_usb driver. The next 6 patches are by Greg Kroah-Hartman and fix URB data parsing for the ems_usb and ucan driver, fix URB anchoring in the etas_es58x, and in the f81604 driver fix URB data parsing, add URB error handling and fix URB anchoring. A patch by me targets the gs_usb driver and fixes interoperability with the CANable-2.5 firmware by always configuring the bit rate before starting the device. The last patch is by Frank Li and fixes a CHECK_DTBS warning for the nxp,sja1000 dt-binding. * tag 'linux-can-fixes-for-7.0-20260302' of git://git.kernel.org/pub/scm/linux/kernel/git/mkl/linux-can: dt-bindings: net: can: nxp,sja1000: add reference to mc-peripheral-props.yaml can: gs_usb: gs_can_open(): always configure bitrates before starting device can: usb: f81604: correctly anchor the urb in the read bulk callback can: usb: f81604: handle bulk write errors properly can: usb: f81604: handle short interrupt urb messages properly can: usb: etas_es58x: correctly anchor the urb in the read bulk callback can: ucan: Fix infinite loop from zero-length messages can: ems_usb: ems_usb_read_bulk_callback(): check the proper length of a message can: esd_usb: add endpoint type validation can: mcp251x: fix deadlock in error path of mcp251x_open can: dummy_can: dummy_can_init(): fix packet statistics can: bcm: fix locking for bcm_op runtime updates ==================== Link: https://patch.msgid.link/20260302152755.1700177-1-mkl@pengutronix.de Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-03-04Merge tag 'wireless-2026-03-04' of ↵Jakub Kicinski
https://git.kernel.org/pub/scm/linux/kernel/git/wireless/wireless Johannes Berg says: ==================== Some more fixes: - mt76 gets three almost identical new length checks - cw1200 & ti: locking fixes - mac80211 has a fix for the recent EML frame handling - rsi driver no longer oddly responds to config, which had triggered a warning in mac80211 - ath12k has two fixes for station statistics handling * tag 'wireless-2026-03-04' of https://git.kernel.org/pub/scm/linux/kernel/git/wireless/wireless: wifi: mt76: Fix possible oob access in mt76_connac2_mac_write_txwi_80211() wifi: mt76: mt7925: Fix possible oob access in mt7925_mac_write_txwi_80211() wifi: mt76: mt7996: Fix possible oob access in mt7996_mac_write_txwi_80211() wifi: wlcore: Fix a locking bug wifi: cw1200: Fix locking in error paths wifi: mac80211: fix missing ieee80211_eml_params member initialization wifi: rsi: Don't default to -EOPNOTSUPP in rsi_mac80211_config wifi: ath12k: fix station lookup failure when disconnecting from AP wifi: ath12k: use correct pdev id when requesting firmware stats ==================== Link: https://patch.msgid.link/20260304112500.169639-3-johannes@sipsolutions.net Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-03-03net/tcp-md5: Fix MAC comparison to be constant-timeEric Biggers
To prevent timing attacks, MACs need to be compared in constant time. Use the appropriate helper function for this. Fixes: cfb6eeb4c860 ("[TCP]: MD5 Signature Option (RFC2385) support.") Fixes: 658ddaaf6694 ("tcp: md5: RST: getting md5 key from listener") Cc: stable@vger.kernel.org Signed-off-by: Eric Biggers <ebiggers@kernel.org> Link: https://patch.msgid.link/20260302203409.13388-1-ebiggers@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-03-03net: ipv4: fix ARM64 alignment fault in multipath hash seedYung Chih Su
`struct sysctl_fib_multipath_hash_seed` contains two u32 fields (user_seed and mp_seed), making it an 8-byte structure with a 4-byte alignment requirement. In `fib_multipath_hash_from_keys()`, the code evaluates the entire struct atomically via `READ_ONCE()`: mp_seed = READ_ONCE(net->ipv4.sysctl_fib_multipath_hash_seed).mp_seed; While this silently works on GCC by falling back to unaligned regular loads which the ARM64 kernel tolerates, it causes a fatal kernel panic when compiled with Clang and LTO enabled. Commit e35123d83ee3 ("arm64: lto: Strengthen READ_ONCE() to acquire when CONFIG_LTO=y") strengthens `READ_ONCE()` to use Load-Acquire instructions (`ldar` / `ldapr`) to prevent compiler reordering bugs under Clang LTO. Since the macro evaluates the full 8-byte struct, Clang emits a 64-bit `ldar` instruction. ARM64 architecture strictly requires `ldar` to be naturally aligned, thus executing it on a 4-byte aligned address triggers a strict Alignment Fault (FSC = 0x21). Fix the read side by moving the `READ_ONCE()` directly to the `u32` member, which emits a safe 32-bit `ldar Wn`. Furthermore, Eric Dumazet pointed out that `WRITE_ONCE()` on the entire struct in `proc_fib_multipath_hash_set_seed()` is also flawed. Analysis shows that Clang splits this 8-byte write into two separate 32-bit `str` instructions. While this avoids an alignment fault, it destroys atomicity and exposes a tear-write vulnerability. Fix this by explicitly splitting the write into two 32-bit `WRITE_ONCE()` operations. Finally, add the missing `READ_ONCE()` when reading `user_seed` in `proc_fib_multipath_hash_seed()` to ensure proper pairing and concurrency safety. Fixes: 4ee2a8cace3f ("net: ipv4: Add a sysctl to set multipath hash seed") Signed-off-by: Yung Chih Su <yuuchihsu@gmail.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20260302060247.7066-1-yuuchihsu@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-03-03net/tcp-ao: Fix MAC comparison to be constant-timeEric Biggers
To prevent timing attacks, MACs need to be compared in constant time. Use the appropriate helper function for this. Fixes: 0a3a809089eb ("net/tcp: Verify inbound TCP-AO signed segments") Cc: stable@vger.kernel.org Signed-off-by: Eric Biggers <ebiggers@kernel.org> Reviewed-by: Dmitry Safonov <0x7f454c46@gmail.com> Link: https://patch.msgid.link/20260302203600.13561-1-ebiggers@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-03-03ipv6: fix NULL pointer deref in ip6_rt_get_dev_rcu()Jakub Kicinski
l3mdev_master_dev_rcu() can return NULL when the slave device is being un-slaved from a VRF. All other callers deal with this, but we lost the fallback to loopback in ip6_rt_pcpu_alloc() -> ip6_rt_get_dev_rcu() with commit 4832c30d5458 ("net: ipv6: put host and anycast routes on device with address"). KASAN: null-ptr-deref in range [0x0000000000000108-0x000000000000010f] RIP: 0010:ip6_rt_pcpu_alloc (net/ipv6/route.c:1418) Call Trace: ip6_pol_route (net/ipv6/route.c:2318) fib6_rule_lookup (net/ipv6/fib6_rules.c:115) ip6_route_output_flags (net/ipv6/route.c:2607) vrf_process_v6_outbound (drivers/net/vrf.c:437) I was tempted to rework the un-slaving code to clear the flag first and insert synchronize_rcu() before we remove the upper. But looks like the explicit fallback to loopback_dev is an established pattern. And I guess avoiding the synchronize_rcu() is nice, too. Fixes: 4832c30d5458 ("net: ipv6: put host and anycast routes on device with address") Reviewed-by: David Ahern <dsahern@kernel.org> Link: https://patch.msgid.link/20260301194548.927324-1-kuba@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-03-03net: Fix rcu_tasks stall in threaded busypollYiFei Zhu
I was debugging a NIC driver when I noticed that when I enable threaded busypoll, bpftrace hangs when starting up. dmesg showed: rcu_tasks_wait_gp: rcu_tasks grace period number 85 (since boot) is 10658 jiffies old. rcu_tasks_wait_gp: rcu_tasks grace period number 85 (since boot) is 40793 jiffies old. rcu_tasks_wait_gp: rcu_tasks grace period number 85 (since boot) is 131273 jiffies old. rcu_tasks_wait_gp: rcu_tasks grace period number 85 (since boot) is 402058 jiffies old. INFO: rcu_tasks detected stalls on tasks: 00000000769f52cd: .N nvcsw: 2/2 holdout: 1 idle_cpu: -1/64 task:napi/eth2-8265 state:R running task stack:0 pid:48300 tgid:48300 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: <TASK> ? napi_threaded_poll_loop+0x27c/0x2c0 ? __pfx_napi_threaded_poll+0x10/0x10 ? napi_threaded_poll+0x26/0x80 ? kthread+0xfa/0x240 ? __pfx_kthread+0x10/0x10 ? ret_from_fork+0x31/0x50 ? __pfx_kthread+0x10/0x10 ? ret_from_fork_asm+0x1a/0x30 </TASK> The cause is that in threaded busypoll, the main loop is in napi_threaded_poll rather than napi_threaded_poll_loop, where the latter rarely iterates more than once within its loop. For rcu_softirq_qs_periodic inside napi_threaded_poll_loop to report its qs state, the last_qs must be 100ms behind, and this can't happen because napi_threaded_poll_loop rarely iterates in threaded busypoll, and each time napi_threaded_poll_loop is called last_qs is reset to latest jiffies. This patch changes so that in threaded busypoll, last_qs is saved in the outer napi_threaded_poll, and whether busy_poll_last_qs is NULL indicates whether napi_threaded_poll_loop is called for busypoll. This way last_qs would not reset to latest jiffies on each invocation of napi_threaded_poll_loop. Fixes: c18d4b190a46 ("net: Extend NAPI threaded polling to allow kthread based busy polling") Cc: stable@vger.kernel.org Signed-off-by: YiFei Zhu <zhuyifei@google.com> Reviewed-by: Samiullah Khawaja <skhawaja@google.com> Link: https://patch.msgid.link/20260227221937.1060857-1-zhuyifei@google.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2026-03-03net/rds: Fix circular locking dependency in rds_tcp_tuneAllison Henderson
syzbot reported a circular locking dependency in rds_tcp_tune() where sk_net_refcnt_upgrade() is called while holding the socket lock: ====================================================== WARNING: possible circular locking dependency detected ====================================================== kworker/u10:8/15040 is trying to acquire lock: ffffffff8e9aaf80 (fs_reclaim){+.+.}-{0:0}, at: __kmalloc_cache_noprof+0x4b/0x6f0 but task is already holding lock: ffff88805a3c1ce0 (k-sk_lock-AF_INET6){+.+.}-{0:0}, at: rds_tcp_tune+0xd7/0x930 The issue occurs because sk_net_refcnt_upgrade() performs memory allocation (via get_net_track() -> ref_tracker_alloc()) while the socket lock is held, creating a circular dependency with fs_reclaim. Fix this by moving sk_net_refcnt_upgrade() outside the socket lock critical section. This is safe because the fields modified by the sk_net_refcnt_upgrade() call (sk_net_refcnt, ns_tracker) are not accessed by any concurrent code path at this point. v2: - Corrected fixes tag - check patch line wrap nits - ai commentary nits Reported-by: syzbot+2e2cf5331207053b8106@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=2e2cf5331207053b8106 Fixes: 3a58f13a881e ("net: rds: acquire refcount on TCP sockets") Signed-off-by: Allison Henderson <achender@kernel.org> Link: https://patch.msgid.link/20260227202336.167757-1-achender@kernel.org Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2026-03-03wifi: mac80211: fix missing ieee80211_eml_params member initializationMeiChia Chiu
The missing initialization causes driver to misinterpret the EML control bitmap, resulting in incorrect link bitmap handling. Fixes: 0d95280a2d54e ("wifi: mac80211: Add eMLSR/eMLMR action frame parsing support") Signed-off-by: MeiChia Chiu <MeiChia.Chiu@mediatek.com> Acked-by: Lorenzo Bianconi <lorenzo@kernel.org> Link: https://patch.msgid.link/20260303054725.471548-1-MeiChia.Chiu@mediatek.com Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2026-03-02can: bcm: fix locking for bcm_op runtime updatesOliver Hartkopp
Commit c2aba69d0c36 ("can: bcm: add locking for bcm_op runtime updates") added a locking for some variables that can be modified at runtime when updating the sending bcm_op with a new TX_SETUP command in bcm_tx_setup(). Usually the RX_SETUP only handles and filters incoming traffic with one exception: When the RX_RTR_FRAME flag is set a predefined CAN frame is sent when a specific RTR frame is received. Therefore the rx bcm_op uses bcm_can_tx() which uses the bcm_tx_lock that was only initialized in bcm_tx_setup(). Add the missing spin_lock_init() when allocating the bcm_op in bcm_rx_setup() to handle the RTR case properly. Fixes: c2aba69d0c36 ("can: bcm: add locking for bcm_op runtime updates") Reported-by: syzbot+5b11eccc403dd1cea9f8@syzkaller.appspotmail.com Closes: https://lore.kernel.org/linux-can/699466e4.a70a0220.2c38d7.00ff.GAE@google.com/ Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net> Link: https://patch.msgid.link/20260218-bcm_spin_lock_init-v1-1-592634c8a5b5@hartkopp.net Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2026-02-28atm: lec: fix null-ptr-deref in lec_arp_clear_vccsJiayuan Chen
syzkaller reported a null-ptr-deref in lec_arp_clear_vccs(). This issue can be easily reproduced using the syzkaller reproducer. In the ATM LANE (LAN Emulation) module, the same atm_vcc can be shared by multiple lec_arp_table entries (e.g., via entry->vcc or entry->recv_vcc). When the underlying VCC is closed, lec_vcc_close() iterates over all ARP entries and calls lec_arp_clear_vccs() for each matched entry. For example, when lec_vcc_close() iterates through the hlists in priv->lec_arp_empty_ones or other ARP tables: 1. In the first iteration, for the first matched ARP entry sharing the VCC, lec_arp_clear_vccs() frees the associated vpriv (which is vcc->user_back) and sets vcc->user_back to NULL. 2. In the second iteration, for the next matched ARP entry sharing the same VCC, lec_arp_clear_vccs() is called again. It obtains a NULL vpriv from vcc->user_back (via LEC_VCC_PRIV(vcc)) and then attempts to dereference it via `vcc->pop = vpriv->old_pop`, leading to a null-ptr-deref crash. Fix this by adding a null check for vpriv before dereferencing it. If vpriv is already NULL, it means the VCC has been cleared by a previous call, so we can safely skip the cleanup and just clear the entry's vcc/recv_vcc pointers. The entire cleanup block (including vcc_release_async()) is placed inside the vpriv guard because a NULL vpriv indicates the VCC has already been fully released by a prior iteration — repeating the teardown would redundantly set flags and trigger callbacks on an already-closing socket. The Fixes tag points to the initial commit because the entry->vcc path has been vulnerable since the original code. The entry->recv_vcc path was later added by commit 8d9f73c0ad2f ("atm: fix a memory leak of vcc->user_back") with the same pattern, and both paths are fixed here. Reported-by: syzbot+72e3ea390c305de0e259@syzkaller.appspotmail.com Closes: https://lore.kernel.org/all/68c95a83.050a0220.3c6139.0e5c.GAE@google.com/T/ Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Suggested-by: Dan Carpenter <dan.carpenter@linaro.org> Reviewed-by: Simon Horman <horms@kernel.org> Signed-off-by: Jiayuan Chen <jiayuan.chen@shopee.com> Link: https://patch.msgid.link/20260225123250.189289-1-jiayuan.chen@linux.dev Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-02-28xsk: Fix zero-copy AF_XDP fragment dropNikhil P. Rao
AF_XDP should ensure that only a complete packet is sent to application. In the zero-copy case, if the Rx queue gets full as fragments are being enqueued, the remaining fragments are dropped. For the multi-buffer case, add a check to ensure that the Rx queue has enough space for all fragments of a packet before starting to enqueue them. Fixes: 24ea50127ecf ("xsk: support mbuf on ZC RX") Signed-off-by: Nikhil P. Rao <nikhil.rao@amd.com> Link: https://patch.msgid.link/20260225000456.107806-3-nikhil.rao@amd.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-02-28xsk: Fix fragment node deletion to prevent buffer leakNikhil P. Rao
After commit b692bf9a7543 ("xsk: Get rid of xdp_buff_xsk::xskb_list_node"), the list_node field is reused for both the xskb pool list and the buffer free list, this causes a buffer leak as described below. xp_free() checks if a buffer is already on the free list using list_empty(&xskb->list_node). When list_del() is used to remove a node from the xskb pool list, it doesn't reinitialize the node pointers. This means list_empty() will return false even after the node has been removed, causing xp_free() to incorrectly skip adding the buffer to the free list. Fix this by using list_del_init() instead of list_del() in all fragment handling paths, this ensures the list node is reinitialized after removal, allowing the list_empty() to work correctly. Fixes: b692bf9a7543 ("xsk: Get rid of xdp_buff_xsk::xskb_list_node") Acked-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com> Signed-off-by: Nikhil P. Rao <nikhil.rao@amd.com> Link: https://patch.msgid.link/20260225000456.107806-2-nikhil.rao@amd.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-02-28tcp: give up on stronger sk_rcvbuf checks (for now)Jakub Kicinski
We hit another corner case which leads to TcpExtTCPRcvQDrop Connections which send RPCs in the 20-80kB range over loopback experience spurious drops. The exact conditions for most of the drops I investigated are that: - socket exchanged >1MB of data so its not completely fresh - rcvbuf is around 128kB (default, hasn't grown) - there is ~60kB of data in rcvq - skb > 64kB arrives The sum of skb->len (!) of both of the skbs (the one already in rcvq and the arriving one) is larger than rwnd. My suspicion is that this happens because __tcp_select_window() rounds the rwnd up to (1 << wscale) if less than half of the rwnd has been consumed. Eric suggests that given the number of Fixes we already have pointing to 1d2fbaad7cd8 it's probably time to give up on it, until a bigger revamp of rmem management. Also while we could risk tweaking the rwnd math, there are other drops on workloads I investigated, after the commit in question, not explained by this phenomenon. Suggested-by: Eric Dumazet <edumazet@google.com> Link: https://lore.kernel.org/20260225122355.585fd57b@kernel.org Fixes: 1d2fbaad7cd8 ("tcp: stronger sk_rcvbuf checks") Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20260227003359.2391017-1-kuba@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-02-28udp: Unhash auto-bound connected sk from 4-tuple hash table when disconnected.Kuniyuki Iwashima
Let's say we bind() an UDP socket to the wildcard address with a non-zero port, connect() it to an address, and disconnect it from the address. bind() sets SOCK_BINDPORT_LOCK on sk->sk_userlocks (but not SOCK_BINDADDR_LOCK), and connect() calls udp_lib_hash4() to put the socket into the 4-tuple hash table. Then, __udp_disconnect() calls sk->sk_prot->rehash(sk). It computes a new hash based on the wildcard address and moves the socket to a new slot in the 4-tuple hash table, leaving a garbage in the chain that no packet hits. Let's remove such a socket from 4-tuple hash table when disconnected. Note that udp_sk(sk)->udp_portaddr_hash needs to be udpated after udp_hash4_dec(hslot2) in udp_unhash4(). Fixes: 78c91ae2c6de ("ipv4/udp: Add 4-tuple hash for connected socket") Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20260227035547.3321327-1-kuniyu@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-02-27net/sched: Only allow act_ct to bind to clsact/ingress qdiscs and shared blocksVictor Nogueira
As Paolo said earlier [1]: "Since the blamed commit below, classify can return TC_ACT_CONSUMED while the current skb being held by the defragmentation engine. As reported by GangMin Kim, if such packet is that may cause a UaF when the defrag engine later on tries to tuch again such packet." act_ct was never meant to be used in the egress path, however some users are attaching it to egress today [2]. Attempting to reach a middle ground, we noticed that, while most qdiscs are not handling TC_ACT_CONSUMED, clsact/ingress qdiscs are. With that in mind, we address the issue by only allowing act_ct to bind to clsact/ingress qdiscs and shared blocks. That way it's still possible to attach act_ct to egress (albeit only with clsact). [1] https://lore.kernel.org/netdev/674b8cbfc385c6f37fb29a1de08d8fe5c2b0fbee.1771321118.git.pabeni@redhat.com/ [2] https://lore.kernel.org/netdev/cc6bfb4a-4a2b-42d8-b9ce-7ef6644fb22b@ovn.org/ Reported-by: GangMin Kim <km.kim1503@gmail.com> Fixes: 3f14b377d01d ("net/sched: act_ct: fix skb leak and crash on ooo frags") CC: stable@vger.kernel.org Signed-off-by: Victor Nogueira <victor@mojatatu.com> Acked-by: Jamal Hadi Salim <jhs@mojatatu.com> Link: https://patch.msgid.link/20260225134349.1287037-1-victor@mojatatu.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-02-27net/sched: sch_cake: fixup cake_mq rate adjustment for diffserv configJonas Köppeler
cake_mq's rate adjustment during the sync periods did not adjust the rates for every tin in a diffserv config. This lead to inconsistencies of rates between the tins. Fix this by setting the rates for all tins during synchronization. Fixes: 1bddd758bac2 ("net/sched: sch_cake: share shaper state across sub-instances of cake_mq") Signed-off-by: Jonas Köppeler <j.koeppeler@tu-berlin.de> Acked-by: Toke Høiland-Jørgensen <toke@toke.dk> Link: https://patch.msgid.link/20260226-cake-mq-skip-sync-bandwidth-unlimited-v1-2-01830bb4db87@tu-berlin.de Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-02-27net/sched: sch_cake: avoid sync overhead when unlimitedJonas Köppeler
Skip inter-instance sync when no rate limit is configured, as it serves no purpose and only adds overhead. Fixes: 1bddd758bac2 ("net/sched: sch_cake: share shaper state across sub-instances of cake_mq") Signed-off-by: Jonas Köppeler <j.koeppeler@tu-berlin.de> Acked-by: Toke Høiland-Jørgensen <toke@toke.dk> Link: https://patch.msgid.link/20260226-cake-mq-skip-sync-bandwidth-unlimited-v1-1-01830bb4db87@tu-berlin.de Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-02-27inet: annotate data-races around isk->inet_numEric Dumazet
UDP/TCP lookups are using RCU, thus isk->inet_num accesses should use READ_ONCE() and WRITE_ONCE() where needed. Fixes: 3ab5aee7fe84 ("net: Convert TCP & DCCP hash tables to use RCU / hlist_nulls") Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com> Link: https://patch.msgid.link/20260225203545.1512417-1-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-02-27net/sched: act_gate: snapshot parameters with RCU on replacePaul Moses
The gate action can be replaced while the hrtimer callback or dump path is walking the schedule list. Convert the parameters to an RCU-protected snapshot and swap updates under tcf_lock, freeing the previous snapshot via call_rcu(). When REPLACE omits the entry list, preserve the existing schedule so the effective state is unchanged. Fixes: a51c328df310 ("net: qos: introduce a gate control flow action") Cc: stable@vger.kernel.org Signed-off-by: Paul Moses <p@1g4.org> Tested-by: Vladimir Oltean <vladimir.oltean@nxp.com> Acked-by: Jamal Hadi Salim <jhs@mojatatu.com> Reviewed-by: Victor Nogueira <victor@mojatatu.com> Link: https://patch.msgid.link/20260223150512.2251594-2-p@1g4.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-02-26bridge: Check relevant per-VLAN options in VLAN range groupingDanielle Ratson
The br_vlan_opts_eq_range() function determines if consecutive VLANs can be grouped together in a range for compact netlink notifications. It currently checks state, tunnel info, and multicast router configuration, but misses two categories of per-VLAN options that affect the output: 1. User-visible priv_flags (neigh_suppress, mcast_enabled) 2. Port multicast context (mcast_max_groups, mcast_n_groups) When VLANs have different settings for these options, they are incorrectly grouped into ranges, causing netlink notifications to report only one VLAN's settings for the entire range. Fix by checking priv_flags equality, but only for flags that affect netlink output (BR_VLFLAG_NEIGH_SUPPRESS_ENABLED and BR_VLFLAG_MCAST_ENABLED), and comparing multicast context (mcast_max_groups and mcast_n_groups). Example showing the bugs before the fix: $ bridge vlan set vid 10 dev dummy1 neigh_suppress on $ bridge vlan set vid 11 dev dummy1 neigh_suppress off $ bridge -d vlan show dev dummy1 port vlan-id dummy1 10-11 ... neigh_suppress on $ bridge vlan set vid 10 dev dummy1 mcast_max_groups 100 $ bridge vlan set vid 11 dev dummy1 mcast_max_groups 200 $ bridge -d vlan show dev dummy1 port vlan-id dummy1 10-11 ... mcast_max_groups 100 After the fix, VLANs 10 and 11 are shown as separate entries with their correct individual settings. Fixes: a1aee20d5db2 ("net: bridge: Add netlink knobs for number / maximum MDB entries") Fixes: 83f6d600796c ("bridge: vlan: Allow setting VLAN neighbor suppression state") Signed-off-by: Danielle Ratson <danieller@nvidia.com> Reviewed-by: Ido Schimmel <idosch@nvidia.com> Acked-by: Nikolay Aleksandrov <razor@blackwall.org> Link: https://patch.msgid.link/20260225143956.3995415-2-danieller@nvidia.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-02-26net: annotate data-races around sk->sk_{data_ready,write_space}Eric Dumazet
skmsg (and probably other layers) are changing these pointers while other cpus might read them concurrently. Add corresponding READ_ONCE()/WRITE_ONCE() annotations for UDP, TCP and AF_UNIX. Fixes: 604326b41a6f ("bpf, sockmap: convert to generic sk_msg interface") Reported-by: syzbot+87f770387a9e5dc6b79b@syzkaller.appspotmail.com Closes: https://lore.kernel.org/netdev/699ee9fc.050a0220.1cd54b.0009.GAE@google.com/ Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: John Fastabend <john.fastabend@gmail.com> Cc: Jakub Sitnicki <jakub@cloudflare.com> Cc: Willem de Bruijn <willemdebruijn.kernel@gmail.com> Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com> Link: https://patch.msgid.link/20260225131547.1085509-1-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-02-26Merge tag 'batadv-net-pullrequest-20260225' of ↵Jakub Kicinski
https://git.open-mesh.org/linux-merge Simon Wunderlich says: ==================== Here is a batman-adv bugfix: - Avoid double-rtnl_lock ELP metric worker, by Sven Eckelmann * tag 'batadv-net-pullrequest-20260225' of https://git.open-mesh.org/linux-merge: batman-adv: Avoid double-rtnl_lock ELP metric worker ==================== Link: https://patch.msgid.link/20260225084614.229077-1-sw@simonwunderlich.de Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-02-26net/sched: ets: fix divide by zero in the offload pathDavide Caratti
Offloading ETS requires computing each class' WRR weight: this is done by averaging over the sums of quanta as 'q_sum' and 'q_psum'. Using unsigned int, the same integer size as the individual DRR quanta, can overflow and even cause division by zero, like it happened in the following splat: Oops: divide error: 0000 [#1] SMP PTI CPU: 13 UID: 0 PID: 487 Comm: tc Tainted: G E 6.19.0-virtme #45 PREEMPT(full) Tainted: [E]=UNSIGNED_MODULE Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 RIP: 0010:ets_offload_change+0x11f/0x290 [sch_ets] Code: e4 45 31 ff eb 03 41 89 c7 41 89 cb 89 ce 83 f9 0f 0f 87 b7 00 00 00 45 8b 08 31 c0 45 01 cc 45 85 c9 74 09 41 6b c4 64 31 d2 <41> f7 f2 89 c2 44 29 fa 45 89 df 41 83 fb 0f 0f 87 c7 00 00 00 44 RSP: 0018:ffffd0a180d77588 EFLAGS: 00010246 RAX: 00000000ffffff38 RBX: ffff8d3d482ca000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffd0a180d77660 RBP: ffffd0a180d77690 R08: ffff8d3d482ca2d8 R09: 00000000fffffffe R10: 0000000000000000 R11: 0000000000000000 R12: 00000000fffffffe R13: ffff8d3d472f2000 R14: 0000000000000003 R15: 0000000000000000 FS: 00007f440b6c2740(0000) GS:ffff8d3dc9803000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000003cdd2000 CR3: 0000000007b58002 CR4: 0000000000172ef0 Call Trace: <TASK> ets_qdisc_change+0x870/0xf40 [sch_ets] qdisc_create+0x12b/0x540 tc_modify_qdisc+0x6d7/0xbd0 rtnetlink_rcv_msg+0x168/0x6b0 netlink_rcv_skb+0x5c/0x110 netlink_unicast+0x1d6/0x2b0 netlink_sendmsg+0x22e/0x470 ____sys_sendmsg+0x38a/0x3c0 ___sys_sendmsg+0x99/0xe0 __sys_sendmsg+0x8a/0xf0 do_syscall_64+0x111/0xf80 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f440b81c77e Code: 4d 89 d8 e8 d4 bc 00 00 4c 8b 5d f8 41 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 11 c9 c3 0f 1f 80 00 00 00 00 48 8b 45 10 0f 05 <c9> c3 83 e2 39 83 fa 08 75 e7 e8 13 ff ff ff 0f 1f 00 f3 0f 1e fa RSP: 002b:00007fff951e4c10 EFLAGS: 00000202 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 0000000000481820 RCX: 00007f440b81c77e RDX: 0000000000000000 RSI: 00007fff951e4cd0 RDI: 0000000000000003 RBP: 00007fff951e4c20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 00007fff951f4fa8 R13: 00000000699ddede R14: 00007f440bb01000 R15: 0000000000486980 </TASK> Modules linked in: sch_ets(E) netdevsim(E) ---[ end trace 0000000000000000 ]--- RIP: 0010:ets_offload_change+0x11f/0x290 [sch_ets] Code: e4 45 31 ff eb 03 41 89 c7 41 89 cb 89 ce 83 f9 0f 0f 87 b7 00 00 00 45 8b 08 31 c0 45 01 cc 45 85 c9 74 09 41 6b c4 64 31 d2 <41> f7 f2 89 c2 44 29 fa 45 89 df 41 83 fb 0f 0f 87 c7 00 00 00 44 RSP: 0018:ffffd0a180d77588 EFLAGS: 00010246 RAX: 00000000ffffff38 RBX: ffff8d3d482ca000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffd0a180d77660 RBP: ffffd0a180d77690 R08: ffff8d3d482ca2d8 R09: 00000000fffffffe R10: 0000000000000000 R11: 0000000000000000 R12: 00000000fffffffe R13: ffff8d3d472f2000 R14: 0000000000000003 R15: 0000000000000000 FS: 00007f440b6c2740(0000) GS:ffff8d3dc9803000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000003cdd2000 CR3: 0000000007b58002 CR4: 0000000000172ef0 Kernel panic - not syncing: Fatal exception Kernel Offset: 0x30000000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff) ---[ end Kernel panic - not syncing: Fatal exception ]--- Fix this using 64-bit integers for 'q_sum' and 'q_psum'. Cc: stable@vger.kernel.org Fixes: d35eb52bd2ac ("net: sch_ets: Make the ETS qdisc offloadable") Signed-off-by: Davide Caratti <dcaratti@redhat.com> Reviewed-by: Jamal Hadi Salim <jhs@mojatatu.com> Reviewed-by: Petr Machata <petrm@nvidia.com> Link: https://patch.msgid.link/28504887df314588c7255e9911769c36f751edee.1771964872.git.dcaratti@redhat.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-02-26Merge tag 'net-7.0-rc2' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net Pull networking fixes from Paolo Abeni: "Including fixes from IPsec, Bluetooth and netfilter Current release - regressions: - wifi: fix dev_alloc_name() return value check - rds: fix recursive lock in rds_tcp_conn_slots_available Current release - new code bugs: - vsock: lock down child_ns_mode as write-once Previous releases - regressions: - core: - do not pass flow_id to set_rps_cpu() - consume xmit errors of GSO frames - netconsole: avoid OOB reads, msg is not nul-terminated - netfilter: h323: fix OOB read in decode_choice() - tcp: re-enable acceptance of FIN packets when RWIN is 0 - udplite: fix null-ptr-deref in __udp_enqueue_schedule_skb(). - wifi: brcmfmac: fix potential kernel oops when probe fails - phy: register phy led_triggers during probe to avoid AB-BA deadlock - eth: - bnxt_en: fix deleting of Ntuple filters - wan: farsync: fix use-after-free bugs caused by unfinished tasklets - xscale: check for PTP support properly Previous releases - always broken: - tcp: fix potential race in tcp_v6_syn_recv_sock() - kcm: fix zero-frag skb in frag_list on partial sendmsg error - xfrm: - fix race condition in espintcp_close() - always flush state and policy upon NETDEV_UNREGISTER event - bluetooth: - purge error queues in socket destructors - fix response to L2CAP_ECRED_CONN_REQ - eth: - mlx5: - fix circular locking dependency in dump - fix "scheduling while atomic" in IPsec MAC address query - gve: fix incorrect buffer cleanup for QPL - team: avoid NETDEV_CHANGEMTU event when unregistering slave - usb: validate USB endpoints" * tag 'net-7.0-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (72 commits) netfilter: nf_conntrack_h323: fix OOB read in decode_choice() dpaa2-switch: validate num_ifs to prevent out-of-bounds write net: consume xmit errors of GSO frames vsock: document write-once behavior of the child_ns_mode sysctl vsock: lock down child_ns_mode as write-once selftests/vsock: change tests to respect write-once child ns mode net/mlx5e: Fix "scheduling while atomic" in IPsec MAC address query net/mlx5: Fix missing devlink lock in SRIOV enable error path net/mlx5: E-switch, Clear legacy flag when moving to switchdev net/mlx5: LAG, disable MPESW in lag_disable_change() net/mlx5: DR, Fix circular locking dependency in dump selftests: team: Add a reference count leak test team: avoid NETDEV_CHANGEMTU event when unregistering slave net: mana: Fix double destroy_workqueue on service rescan PCI path MAINTAINERS: Update maintainer entry for QUALCOMM ETHQOS ETHERNET DRIVER dpll: zl3073x: Remove redundant cleanup in devm_dpll_init() selftests/net: packetdrill: Verify acceptance of FIN packets when RWIN is 0 tcp: re-enable acceptance of FIN packets when RWIN is 0 vsock: Use container_of() to get net namespace in sysctl handlers net: usb: kaweth: validate USB endpoints ...
2026-02-26netfilter: nf_conntrack_h323: fix OOB read in decode_choice()Vahagn Vardanian
In decode_choice(), the boundary check before get_len() uses the variable `len`, which is still 0 from its initialization at the top of the function: unsigned int type, ext, len = 0; ... if (ext || (son->attr & OPEN)) { BYTE_ALIGN(bs); if (nf_h323_error_boundary(bs, len, 0)) /* len is 0 here */ return H323_ERROR_BOUND; len = get_len(bs); /* OOB read */ When the bitstream is exactly consumed (bs->cur == bs->end), the check nf_h323_error_boundary(bs, 0, 0) evaluates to (bs->cur + 0 > bs->end), which is false. The subsequent get_len() call then dereferences *bs->cur++, reading 1 byte past the end of the buffer. If that byte has bit 7 set, get_len() reads a second byte as well. This can be triggered remotely by sending a crafted Q.931 SETUP message with a User-User Information Element containing exactly 2 bytes of PER-encoded data ({0x08, 0x00}) to port 1720 through a firewall with the nf_conntrack_h323 helper active. The decoder fully consumes the PER buffer before reaching this code path, resulting in a 1-2 byte heap-buffer-overflow read confirmed by AddressSanitizer. Fix this by checking for 2 bytes (the maximum that get_len() may read) instead of the uninitialized `len`. This matches the pattern used at every other get_len() call site in the same file, where the caller checks for 2 bytes of available data before calling get_len(). Fixes: ec8a8f3c31dd ("netfilter: nf_ct_h323: Extend nf_h323_error_boundary to work on bits as well") Signed-off-by: Vahagn Vardanian <vahagn@redrays.io> Signed-off-by: Florian Westphal <fw@strlen.de> Link: https://patch.msgid.link/20260225130619.1248-2-fw@strlen.de Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2026-02-26net: consume xmit errors of GSO framesJakub Kicinski
udpgro_frglist.sh and udpgro_bench.sh are the flakiest tests currently in NIPA. They fail in the same exact way, TCP GRO test stalls occasionally and the test gets killed after 10min. These tests use veth to simulate GRO. They attach a trivial ("return XDP_PASS;") XDP program to the veth to force TSO off and NAPI on. Digging into the failure mode we can see that the connection is completely stuck after a burst of drops. The sender's snd_nxt is at sequence number N [1], but the receiver claims to have received (rcv_nxt) up to N + 3 * MSS [2]. Last piece of the puzzle is that senders rtx queue is not empty (let's say the block in the rtx queue is at sequence number N - 4 * MSS [3]). In this state, sender sends a retransmission from the rtx queue with a single segment, and sequence numbers N-4*MSS:N-3*MSS [3]. Receiver sees it and responds with an ACK all the way up to N + 3 * MSS [2]. But sender will reject this ack as TCP_ACK_UNSENT_DATA because it has no recollection of ever sending data that far out [1]. And we are stuck. The root cause is the mess of the xmit return codes. veth returns an error when it can't xmit a frame. We end up with a loss event like this: ------------------------------------------------- | GSO super frame 1 | GSO super frame 2 | |-----------------------------------------------| | seg | seg | seg | seg | seg | seg | seg | seg | | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | ------------------------------------------------- x ok ok <ok>| ok ok ok <x> \\ snd_nxt "x" means packet lost by veth, and "ok" means it went thru. Since veth has TSO disabled in this test it sees individual segments. Segment 1 is on the retransmit queue and will be resent. So why did the sender not advance snd_nxt even tho it clearly did send up to seg 8? tcp_write_xmit() interprets the return code from the core to mean that data has not been sent at all. Since TCP deals with GSO super frames, not individual segment the crux of the problem is that loss of a single segment can be interpreted as loss of all. TCP only sees the last return code for the last segment of the GSO frame (in <> brackets in the diagram above). Of course for the problem to occur we need a setup or a device without a Qdisc. Otherwise Qdisc layer disconnects the protocol layer from the device errors completely. We have multiple ways to fix this. 1) make veth not return an error when it lost a packet. While this is what I think we did in the past, the issue keeps reappearing and it's annoying to debug. The game of whack a mole is not great. 2) fix the damn return codes We only talk about NETDEV_TX_OK and NETDEV_TX_BUSY in the documentation, so maybe we should make the return code from ndo_start_xmit() a boolean. I like that the most, but perhaps some ancient, not-really-networking protocol would suffer. 3) make TCP ignore the errors It is not entirely clear to me what benefit TCP gets from interpreting the result of ip_queue_xmit()? Specifically once the connection is established and we're pushing data - packet loss is just packet loss? 4) this fix Ignore the rc in the Qdisc-less+GSO case, since it's unreliable. We already always return OK in the TCQ_F_CAN_BYPASS case. In the Qdisc-less case let's be a bit more conservative and only mask the GSO errors. This path is taken by non-IP-"networks" like CAN, MCTP etc, so we could regress some ancient thing. This is the simplest, but also maybe the hackiest fix? Similar fix has been proposed by Eric in the past but never committed because original reporter was working with an OOT driver and wasn't providing feedback (see Link). Link: https://lore.kernel.org/CANn89iJcLepEin7EtBETrZ36bjoD9LrR=k4cfwWh046GB+4f9A@mail.gmail.com Fixes: 1f59533f9ca5 ("qdisc: validate frames going through the direct_xmit path") Signed-off-by: Jakub Kicinski <kuba@kernel.org> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20260223235100.108939-1-kuba@kernel.org Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2026-02-26vsock: lock down child_ns_mode as write-onceBobby Eshleman
Two administrator processes may race when setting child_ns_mode as one process sets child_ns_mode to "local" and then creates a namespace, but another process changes child_ns_mode to "global" between the write and the namespace creation. The first process ends up with a namespace in "global" mode instead of "local". While this can be detected after the fact by reading ns_mode and retrying, it is fragile and error-prone. Make child_ns_mode write-once so that a namespace manager can set it once and be sure it won't change. Writing a different value after the first write returns -EBUSY. This applies to all namespaces, including init_net, where an init process can write "local" to lock all future namespaces into local mode. Fixes: eafb64f40ca4 ("vsock: add netns to vsock core") Suggested-by: Daan De Meyer <daan.j.demeyer@gmail.com> Suggested-by: Stefano Garzarella <sgarzare@redhat.com> Co-developed-by: Stefano Garzarella <sgarzare@redhat.com> Signed-off-by: Stefano Garzarella <sgarzare@redhat.com> Signed-off-by: Bobby Eshleman <bobbyeshleman@meta.com> Reviewed-by: Stefano Garzarella <sgarzare@redhat.com> Link: https://patch.msgid.link/20260223-vsock-ns-write-once-v3-2-c0cde6959923@meta.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2026-02-25Merge tag 'wireless-2026-02-25' of ↵Jakub Kicinski
https://git.kernel.org/pub/scm/linux/kernel/git/wireless/wireless Johannes Berg says: ==================== A good number of fixes: - cfg80211: - cancel rfkill work appropriately - fix radiotap parsing to correctly reject field 18 - fix wext (yes...) off-by-one for IGTK key ID - mac80211: - fix for mesh NULL pointer dereference - fix for stack out-of-bounds (2 bytes) write on specific multi-link action frames - set default WMM parameters for all links - mwifiex: check dev_alloc_name() return value correctly - libertas: fix potential timer use-after-free - brcmfmac: fix crash on probe failure * tag 'wireless-2026-02-25' of https://git.kernel.org/pub/scm/linux/kernel/git/wireless/wireless: wifi: mac80211: fix NULL pointer dereference in mesh_rx_csa_frame() wifi: mac80211: bounds-check link_id in ieee80211_ml_reconfiguration wifi: mac80211: set default WMM parameters on all links wifi: libertas: fix use-after-free in lbs_free_adapter() wifi: mwifiex: Fix dev_alloc_name() return value check wifi: brcmfmac: Fix potential kernel oops when probe fails wifi: radiotap: reject radiotap with unknown bits wifi: cfg80211: cancel rfkill_block work in wiphy_unregister() wifi: cfg80211: wext: fix IGTK key ID off-by-one ==================== Link: https://patch.msgid.link/20260225113159.360574-3-johannes@sipsolutions.net Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-02-25tcp: re-enable acceptance of FIN packets when RWIN is 0Simon Baatz
Commit 2bd99aef1b19 ("tcp: accept bare FIN packets under memory pressure") allowed accepting FIN packets in tcp_data_queue() even when the receive window was closed, to prevent ACK/FIN loops with broken clients. Such a FIN packet is in sequence, but because the FIN consumes a sequence number, it extends beyond the window. Before commit 9ca48d616ed7 ("tcp: do not accept packets beyond window"), tcp_sequence() only required the seq to be within the window. After that change, the entire packet (including the FIN) must fit within the window. As a result, such FIN packets are now dropped and the handling path is no longer reached. Be more lenient by not counting the sequence number consumed by the FIN when calling tcp_sequence(), restoring the previous behavior for cases where only the FIN extends beyond the window. Fixes: 9ca48d616ed7 ("tcp: do not accept packets beyond window") Signed-off-by: Simon Baatz <gmbnomis@gmail.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com> Link: https://patch.msgid.link/20260224-fix_zero_wnd_fin-v2-1-a16677ea7cea@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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