Pull tracing fix from Steven Rostedt:
 "Fix the histogram logic from possibly crashing the kernel

  Working on the histogram code, I found that if you dereference a char
  pointer in a trace event that happens to point to user space, it can
  crash the kernel, as it does no checks of that pointer. I have code
  coming that will do this better, so just remove this ability to treat
  character pointers in trace events as stings in the histogram"

* tag 'trace-v5.14-5' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracing: Do not reference char * as a string in histograms

Pull RCU fixes from Paul McKenney:

 - fix regressions induced by a merge-window change in scheduler
   semantics, which means that smp_processor_id() can no longer be used
   in kthreads using simple affinity to bind themselves to a specific
   CPU.

 - fix a bug in Tasks Trace RCU that was thought to be strictly
   theoretical. However, production workloads have started hitting this,
   so these fixes need to be merged sooner rather than later.

 - fix a minor printk()-format-mismatch issue introduced during the
   merge window.

* 'urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu:
  rcu: Fix pr_info() formats and values in show_rcu_gp_kthreads()
  rcu-tasks: Don't delete holdouts within trc_wait_for_one_reader()
  rcu-tasks: Don't delete holdouts within trc_inspect_reader()
  refscale: Avoid false-positive warnings in ref_scale_reader()
  scftorture: Avoid false-positive warnings in scftorture_invoker()

The histogram logic was allowing events with char * pointers to be used as
normal strings. But it was easy to crash the kernel with:

 # echo 'hist:keys=filename' > events/syscalls/sys_enter_openat/trigger

And open some files, and boom!

 BUG: unable to handle page fault for address: 00007f2ced0c3280
 #PF: supervisor read access in kernel mode
 #PF: error_code(0x0000) - not-present page
 PGD 1173fa067 P4D 1173fa067 PUD 1171b6067 PMD 1171dd067 PTE 0
 Oops: 0000 [#1] PREEMPT SMP
 CPU: 6 PID: 1810 Comm: cat Not tainted 5.13.0-rc5-test+ #61
 Hardware name: Hewlett-Packard HP Compaq Pro 6300 SFF/339A, BIOS K01
v03.03 07/14/2016
 RIP: 0010:strlen+0x0/0x20
 Code: f6 82 80 2a 0b a9 20 74 11 0f b6 50 01 48 83 c0 01 f6 82 80 2a 0b
a9 20 75 ef c3 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 <80> 3f 00 74
10 48 89 f8 48 83 c0 01 80 38 00 75 f7 48 29 f8 c3

 RSP: 0018:ffffbdbf81567b50 EFLAGS: 00010246
 RAX: 0000000000000003 RBX: ffff93815cdb3800 RCX: ffff9382401a22d0
 RDX: 0000000000000100 RSI: 0000000000000000 RDI: 00007f2ced0c3280
 RBP: 0000000000000100 R08: ffff9382409ff074 R09: ffffbdbf81567c98
 R10: ffff9382409ff074 R11: 0000000000000000 R12: ffff9382409ff074
 R13: 0000000000000001 R14: ffff93815a744f00 R15: 00007f2ced0c3280
 FS:  00007f2ced0f8580(0000) GS:ffff93825a800000(0000)
knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: 00007f2ced0c3280 CR3: 0000000107069005 CR4: 00000000001706e0
 Call Trace:
  event_hist_trigger+0x463/0x5f0
  ? find_held_lock+0x32/0x90
  ? sched_clock_cpu+0xe/0xd0
  ? lock_release+0x155/0x440
  ? kernel_init_free_pages+0x6d/0x90
  ? preempt_count_sub+0x9b/0xd0
  ? kernel_init_free_pages+0x6d/0x90
  ? get_page_from_freelist+0x12c4/0x1680
  ? __rb_reserve_next+0xe5/0x460
  ? ring_buffer_lock_reserve+0x12a/0x3f0
  event_triggers_call+0x52/0xe0
  ftrace_syscall_enter+0x264/0x2c0
  syscall_trace_enter.constprop.0+0x1ee/0x210
  do_syscall_64+0x1c/0x80
  entry_SYSCALL_64_after_hwframe+0x44/0xae

Where it triggered a fault on strlen(key) where key was the filename.

The reason is that filename is a char * to user space, and the histogram
code just blindly dereferenced it, with obvious bad results.

I originally tried to use strncpy_from_user/kernel_nofault() but found
that there's other places that its dereferenced and not worth the effort.

Just do not allow "char *" to act like strings.

Link: https://lkml.kernel.org/r/20210715000206.025df9d2@rorschach.local.home

Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Tzvetomir Stoyanov <tz.stoyanov@gmail.com>
Cc: stable@vger.kernel.org
Acked-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Tom Zanussi <zanussi@kernel.org>
Fixes: 79e577cbce4c4 ("tracing: Support string type key properly")
Fixes: 5967bd5c4239 ("tracing: Let filter_assign_type() detect FILTER_PTR_STRING")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

Pull fallthrough fixes from Gustavo Silva:
 "This fixes many fall-through warnings when building with Clang and
  -Wimplicit-fallthrough, and also enables -Wimplicit-fallthrough for
  Clang, globally.

  It's also important to notice that since we have adopted the use of
  the pseudo-keyword macro fallthrough, we also want to avoid having
  more /* fall through */ comments being introduced. Contrary to GCC,
  Clang doesn't recognize any comments as implicit fall-through markings
  when the -Wimplicit-fallthrough option is enabled.

  So, in order to avoid having more comments being introduced, we use
  the option -Wimplicit-fallthrough=5 for GCC, which similar to Clang,
  will cause a warning in case a code comment is intended to be used as
  a fall-through marking. The patch for Makefile also enforces this.

  We had almost 4,000 of these issues for Clang in the beginning, and
  there might be a couple more out there when building some
  architectures with certain configurations. However, with the recent
  fixes I think we are in good shape and it is now possible to enable
  the warning for Clang"

* tag 'Wimplicit-fallthrough-clang-5.14-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gustavoars/linux: (27 commits)
  Makefile: Enable -Wimplicit-fallthrough for Clang
  powerpc/smp: Fix fall-through warning for Clang
  dmaengine: mpc512x: Fix fall-through warning for Clang
  usb: gadget: fsl_qe_udc: Fix fall-through warning for Clang
  powerpc/powernv: Fix fall-through warning for Clang
  MIPS: Fix unreachable code issue
  MIPS: Fix fall-through warnings for Clang
  ASoC: Mediatek: MT8183: Fix fall-through warning for Clang
  power: supply: Fix fall-through warnings for Clang
  dmaengine: ti: k3-udma: Fix fall-through warning for Clang
  s390: Fix fall-through warnings for Clang
  dmaengine: ipu: Fix fall-through warning for Clang
  iommu/arm-smmu-v3: Fix fall-through warning for Clang
  mmc: jz4740: Fix fall-through warning for Clang
  PCI: Fix fall-through warning for Clang
  scsi: libsas: Fix fall-through warning for Clang
  video: fbdev: Fix fall-through warning for Clang
  math-emu: Fix fall-through warning
  cpufreq: Fix fall-through warning for Clang
  drm/msm: Fix fall-through warning in msm_gem_new_impl()
  ...

Pull networking fixes from Jakub Kicinski.
 "Including fixes from bpf and netfilter.

  Current release - regressions:

   - sock: fix parameter order in sock_setsockopt()

  Current release - new code bugs:

   - netfilter: nft_last:
       - fix incorrect arithmetic when restoring last used
       - honor NFTA_LAST_SET on restoration

  Previous releases - regressions:

   - udp: properly flush normal packet at GRO time

   - sfc: ensure correct number of XDP queues; don't allow enabling the
     feature if there isn't sufficient resources to Tx from any CPU

   - dsa: sja1105: fix address learning getting disabled on the CPU port

   - mptcp: addresses a rmem accounting issue that could keep packets in
     subflow receive buffers longer than necessary, delaying MPTCP-level
     ACKs

   - ip_tunnel: fix mtu calculation for ETHER tunnel devices

   - do not reuse skbs allocated from skbuff_fclone_cache in the napi
     skb cache, we'd try to return them to the wrong slab cache

   - tcp: consistently disable header prediction for mptcp

  Previous releases - always broken:

   - bpf: fix subprog poke descriptor tracking use-after-free

   - ipv6:
       - allocate enough headroom in ip6_finish_output2() in case
         iptables TEE is used
       - tcp: drop silly ICMPv6 packet too big messages to avoid
         expensive and pointless lookups (which may serve as a DDOS
         vector)
       - make sure fwmark is copied in SYNACK packets
       - fix 'disable_policy' for forwarded packets (align with IPv4)

   - netfilter: conntrack:
       - do not renew entry stuck in tcp SYN_SENT state
       - do not mark RST in the reply direction coming after SYN packet
         for an out-of-sync entry

   - mptcp: cleanly handle error conditions with MP_JOIN and syncookies

   - mptcp: fix double free when rejecting a join due to port mismatch

   - validate lwtstate->data before returning from skb_tunnel_info()

   - tcp: call sk_wmem_schedule before sk_mem_charge in zerocopy path

   - mt76: mt7921: continue to probe driver when fw already downloaded

   - bonding: fix multiple issues with offloading IPsec to (thru?) bond

   - stmmac: ptp: fix issues around Qbv support and setting time back

   - bcmgenet: always clear wake-up based on energy detection

  Misc:

   - sctp: move 198 addresses from unusable to private scope

   - ptp: support virtual clocks and timestamping

   - openvswitch: optimize operation for key comparison"

* tag 'net-5.14-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (158 commits)
  net: dsa: properly check for the bridge_leave methods in dsa_switch_bridge_leave()
  sfc: add logs explaining XDP_TX/REDIRECT is not available
  sfc: ensure correct number of XDP queues
  sfc: fix lack of XDP TX queues - error XDP TX failed (-22)
  net: fddi: fix UAF in fza_probe
  net: dsa: sja1105: fix address learning getting disabled on the CPU port
  net: ocelot: fix switchdev objects synced for wrong netdev with LAG offload
  net: Use nlmsg_unicast() instead of netlink_unicast()
  octeontx2-pf: Fix uninitialized boolean variable pps
  ipv6: allocate enough headroom in ip6_finish_output2()
  net: hdlc: rename 'mod_init' & 'mod_exit' functions to be module-specific
  net: bridge: multicast: fix MRD advertisement router port marking race
  net: bridge: multicast: fix PIM hello router port marking race
  net: phy: marvell10g: fix differentiation of 88X3310 from 88X3340
  dsa: fix for_each_child.cocci warnings
  virtio_net: check virtqueue_add_sgs() return value
  mptcp: properly account bulk freed memory
  selftests: mptcp: fix case multiple subflows limited by server
  mptcp: avoid processing packet if a subflow reset
  mptcp: fix syncookie process if mptcp can not_accept new subflow
  ...

Add a simple helper that filesystems can use in their parameter parser
to parse the "source" parameter. A few places open-coded this function
and that already caused a bug in the cgroup v1 parser that we fixed.
Let's make it harder to get this wrong by introducing a helper which
performs all necessary checks.

Link: https://syzkaller.appspot.com/bug?id=6312526aba5beae046fdae8f00399f87aab48b12
Cc: Christoph Hellwig <hch@lst.de>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The following sequence can be used to trigger a UAF:

    int fscontext_fd = fsopen("cgroup");
    int fd_null = open("/dev/null, O_RDONLY);
    int fsconfig(fscontext_fd, FSCONFIG_SET_FD, "source", fd_null);
    close_range(3, ~0U, 0);

The cgroup v1 specific fs parser expects a string for the "source"
parameter.  However, it is perfectly legitimate to e.g.  specify a file
descriptor for the "source" parameter.  The fs parser doesn't know what
a filesystem allows there.  So it's a bug to assume that "source" is
always of type fs_value_is_string when it can reasonably also be
fs_value_is_file.

This assumption in the cgroup code causes a UAF because struct
fs_parameter uses a union for the actual value.  Access to that union is
guarded by the param->type member.  Since the cgroup paramter parser
didn't check param->type but unconditionally moved param->string into
fc->source a close on the fscontext_fd would trigger a UAF during
put_fs_context() which frees fc->source thereby freeing the file stashed
in param->file causing a UAF during a close of the fd_null.

Fix this by verifying that param->type is actually a string and report
an error if not.

In follow up patches I'll add a new generic helper that can be used here
and by other filesystems instead of this error-prone copy-pasta fix.
But fixing it in here first makes backporting a it to stable a lot
easier.

Fixes: 8d2451f4994f ("cgroup1: switch to option-by-option parsing")
Reported-by: syzbot+283ce5a46486d6acdbaf@syzkaller.appspotmail.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: <stable@kernel.org>
Cc: syzkaller-bugs <syzkaller-bugs@googlegroups.com>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Fix the following warning:

kernel/debug/gdbstub.c:1049:4: warning: fallthrough annotation in unreachable code [-Wimplicit-fallthrough]
                           fallthrough;
                           ^
   include/linux/compiler_attributes.h:210:41: note: expanded from macro 'fallthrough'
   # define fallthrough                    __attribute__((__fallthrough__)

by placing the fallthrough; statement inside ifdeffery.

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>

Pull irq fixes from Ingo Molnar:
 "Two fixes:

   - Fix a MIPS IRQ handling RCU bug

   - Remove a DocBook annotation for a parameter that doesn't exist
     anymore"

* tag 'irq-urgent-2021-07-11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  irqchip/mips: Fix RCU violation when using irqdomain lookup on interrupt entry
  genirq/irqdesc: Drop excess kernel-doc entry @lookup

Pull scheduler fixes from Ingo Molnar:
 "Three fixes:

   - Fix load tracking bug/inconsistency

   - Fix a sporadic CFS bandwidth constraints enforcement bug

   - Fix a uclamp utilization tracking bug for newly woken tasks"

* tag 'sched-urgent-2021-07-11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/uclamp: Ignore max aggregation if rq is idle
  sched/fair: Fix CFS bandwidth hrtimer expiry type
  sched/fair: Sync load_sum with load_avg after dequeue