Using del_timer() + add_timer() is generally unsafe on SMP,
as noticed by syzbot. Use mod_timer() instead.

kernel BUG at kernel/time/timer.c:1136!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 1026 Comm: kworker/u4:4 Not tainted 4.20.0+ #2
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events_unbound flush_to_ldisc
RIP: 0010:add_timer kernel/time/timer.c:1136 [inline]
RIP: 0010:add_timer+0xa81/0x1470 kernel/time/timer.c:1134
Code: 4d 89 7d 40 48 c7 85 70 fe ff ff 00 00 00 00 c7 85 7c fe ff ff ff ff ff ff 48 89 85 90 fe ff ff e9 e6 f7 ff ff e8 cf 42 12 00 <0f> 0b e8 c8 42 12 00 0f 0b e8 c1 42 12 00 4c 89 bd 60 fe ff ff e9
RSP: 0018:ffff8880a7fdf5a8 EFLAGS: 00010293
RAX: ffff8880a7846340 RBX: dffffc0000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff816f3ee1 RDI: ffff88808a514ff8
RBP: ffff8880a7fdf760 R08: 0000000000000007 R09: ffff8880a7846c58
R10: ffff8880a7846340 R11: 0000000000000000 R12: ffff88808a514ff8
R13: ffff88808a514ff8 R14: ffff88808a514dc0 R15: 0000000000000030
FS:  0000000000000000(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000061c500 CR3: 00000000994d9000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 decode_prio_command drivers/net/hamradio/6pack.c:903 [inline]
 sixpack_decode drivers/net/hamradio/6pack.c:971 [inline]
 sixpack_receive_buf drivers/net/hamradio/6pack.c:457 [inline]
 sixpack_receive_buf+0xf9c/0x1470 drivers/net/hamradio/6pack.c:434
 tty_ldisc_receive_buf+0x164/0x1c0 drivers/tty/tty_buffer.c:465
 tty_port_default_receive_buf+0x114/0x190 drivers/tty/tty_port.c:38
 receive_buf drivers/tty/tty_buffer.c:481 [inline]
 flush_to_ldisc+0x3b2/0x590 drivers/tty/tty_buffer.c:533
 process_one_work+0xd0c/0x1ce0 kernel/workqueue.c:2153
 worker_thread+0x143/0x14a0 kernel/workqueue.c:2296
 kthread+0x357/0x430 kernel/kthread.c:246
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Cc: Andreas Koensgen <ajk@comnets.uni-bremen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

ppp and hamradio have copies of the same code that uses a semaphore
in place of a completion for historic reasons. Make it use the
proper interface instead in all copies.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

Pull tty ioctl updates from Al Viro:
 "This is the compat_ioctl work related to tty ioctls.

  Quite a bit of dead code taken out, all tty-related stuff gone from
  fs/compat_ioctl.c. A bunch of compat bugs fixed - some still remain,
  but all more or less generic tty-related ioctls should be covered
  (remaining issues are in things like driver-private ioctls in a pcmcia
  serial card driver not getting properly handled in 32bit processes on
  64bit host, etc)"

* 'work.tty-ioctl' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (53 commits)
  kill TIOCSERGSTRUCT
  change semantics of ldisc ->compat_ioctl()
  kill TIOCSER[SG]WILD
  synclink_gt(): fix compat_ioctl()
  pty: fix compat ioctls
  compat_ioctl - kill keyboard ioctl handling
  gigaset: add ->compat_ioctl()
  vt_compat_ioctl(): clean up, use compat_ptr() properly
  gigaset: don't try to printk userland buffer contents
  dgnc: don't bother with (empty) stub for TCXONC
  dgnc: leave TIOC[GS]SOFTCAR to ldisc
  remove fallback to drivers for TIOCGICOUNT
  dgnc: break-related ioctls won't reach ->ioctl()
  kill the rest of tty COMPAT_IOCTL() entries
  dgnc: TIOCM... won't reach ->ioctl()
  isdn_tty: TCSBRK{,P} won't reach ->ioctl()
  kill capinc_tty_ioctl()
  take compat TIOC[SG]SERIAL treatment into tty_compat_ioctl()
  synclink: reduce pointless checks in ->ioctl()
  complete ->[sg]et_serial() switchover
  ...

First of all, make it return int.  Returning long when native method
had never allowed that is ridiculous and inconvenient.

More importantly, change the caller; if ldisc ->compat_ioctl() is NULL
or returns -ENOIOCTLCMD, tty_compat_ioctl() will try to feed cmd and
compat_ptr(arg) to ldisc's native ->ioctl().

That simplifies ->compat_ioctl() instances quite a bit - they only
need to deal with ioctls that are neither generic tty ones (those
would get shunted off to tty_ioctl()) nor simple compat pointer ones.

Note that something like TCFLSH won't reach ->compat_ioctl(),
even if ldisc ->ioctl() does handle it - it will be recognized
earlier and passed to tty_ioctl() (and ultimately - ldisc ->ioctl()).

For many ldiscs it means that NULL ->compat_ioctl() does the
right thing.  Those where it won't serve (see e.g. n_r3964.c) are
also easily dealt with - we need to handle the numeric-argument
ioctls (calling the native instance) and, if such would exist,
the ioctls that need layout conversion, etc.

All in-tree ldiscs dealt with.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

In yam_ioctl(), the concrete ioctl command is firstly copied from the
user-space buffer 'ifr->ifr_data' to 'ioctl_cmd' and checked through the
following switch statement. If the command is not as expected, an error
code EINVAL is returned. In the following execution the buffer
'ifr->ifr_data' is copied again in the cases of the switch statement to
specific data structures according to what kind of ioctl command is
requested. However, after the second copy, no re-check is enforced on the
newly-copied command. Given that the buffer 'ifr->ifr_data' is in the user
space, a malicious user can race to change the command between the two
copies. This way, the attacker can inject inconsistent data and cause
undefined behavior.

This patch adds a re-check in each case of the switch statement if there is
a second copy in that case, to re-check whether the command obtained in the
second copy is the same as the one in the first copy. If not, an error code
EINVAL will be returned.

Signed-off-by: Wenwen Wang <wang6495@umn.edu>
Signed-off-by: David S. Miller <davem@davemloft.net>

Variable channel is being assigned but is never used hence it is
redundant and can be removed.

Cleans up two clang warnings:
warning: variable 'channel' set but not used [-Wunused-but-set-variable]

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

The array bpq_eth_addr is only used to get the size of an
address, whereas the bcast_addr is used to set the broadcast
address. This leads to a warning when using clang:
drivers/net/hamradio/bpqether.c:94:13: warning: variable 'bpq_eth_addr' is not
      needed and will not be emitted [-Wunneeded-internal-declaration]
static char bpq_eth_addr[6];
            ^

Remove both variables and use the common eth_broadcast_addr
to set the broadcast address.

Signed-off-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

Pull networking updates from David Miller:

 1) Add Maglev hashing scheduler to IPVS, from Inju Song.

 2) Lots of new TC subsystem tests from Roman Mashak.

 3) Add TCP zero copy receive and fix delayed acks and autotuning with
    SO_RCVLOWAT, from Eric Dumazet.

 4) Add XDP_REDIRECT support to mlx5 driver, from Jesper Dangaard
    Brouer.

 5) Add ttl inherit support to vxlan, from Hangbin Liu.

 6) Properly separate ipv6 routes into their logically independant
    components. fib6_info for the routing table, and fib6_nh for sets of
    nexthops, which thus can be shared. From David Ahern.

 7) Add bpf_xdp_adjust_tail helper, which can be used to generate ICMP
    messages from XDP programs. From Nikita V. Shirokov.

 8) Lots of long overdue cleanups to the r8169 driver, from Heiner
    Kallweit.

 9) Add BTF ("BPF Type Format"), from Martin KaFai Lau.

10) Add traffic condition monitoring to iwlwifi, from Luca Coelho.

11) Plumb extack down into fib_rules, from Roopa Prabhu.

12) Add Flower classifier offload support to igb, from Vinicius Costa
    Gomes.

13) Add UDP GSO support, from Willem de Bruijn.

14) Add documentation for eBPF helpers, from Quentin Monnet.

15) Add TLS tx offload to mlx5, from Ilya Lesokhin.

16) Allow applications to be given the number of bytes available to read
    on a socket via a control message returned from recvmsg(), from
    Soheil Hassas Yeganeh.

17) Add x86_32 eBPF JIT compiler, from Wang YanQing.

18) Add AF_XDP sockets, with zerocopy support infrastructure as well.
    From Björn Töpel.

19) Remove indirect load support from all of the BPF JITs and handle
    these operations in the verifier by translating them into native BPF
    instead. From Daniel Borkmann.

20) Add GRO support to ipv6 gre tunnels, from Eran Ben Elisha.

21) Allow XDP programs to do lookups in the main kernel routing tables
    for forwarding. From David Ahern.

22) Allow drivers to store hardware state into an ELF section of kernel
    dump vmcore files, and use it in cxgb4. From Rahul Lakkireddy.

23) Various RACK and loss detection improvements in TCP, from Yuchung
    Cheng.

24) Add TCP SACK compression, from Eric Dumazet.

25) Add User Mode Helper support and basic bpfilter infrastructure, from
    Alexei Starovoitov.

26) Support ports and protocol values in RTM_GETROUTE, from Roopa
    Prabhu.

27) Support bulking in ->ndo_xdp_xmit() API, from Jesper Dangaard
    Brouer.

28) Add lots of forwarding selftests, from Petr Machata.

29) Add generic network device failover driver, from Sridhar Samudrala.

* ra.kernel.org:/pub/scm/linux/kernel/git/davem/net-next: (1959 commits)
  strparser: Add __strp_unpause and use it in ktls.
  rxrpc: Fix terminal retransmission connection ID to include the channel
  net: hns3: Optimize PF CMDQ interrupt switching process
  net: hns3: Fix for VF mailbox receiving unknown message
  net: hns3: Fix for VF mailbox cannot receiving PF response
  bnx2x: use the right constant
  Revert "net: sched: cls: Fix offloading when ingress dev is vxlan"
  net: dsa: b53: Fix for brcm tag issue in Cygnus SoC
  enic: fix UDP rss bits
  netdev-FAQ: clarify DaveM's position for stable backports
  rtnetlink: validate attributes in do_setlink()
  mlxsw: Add extack messages for port_{un, }split failures
  netdevsim: Add extack error message for devlink reload
  devlink: Add extack to reload and port_{un, }split operations
  net: metrics: add proper netlink validation
  ipmr: fix error path when ipmr_new_table fails
  ip6mr: only set ip6mr_table from setsockopt when ip6mr_new_table succeeds
  net: hns3: remove unused hclgevf_cfg_func_mta_filter
  netfilter: provide udp*_lib_lookup for nf_tproxy
  qed*: Utilize FW 8.37.2.0
  ...

Variants of proc_create{,_data} that directly take a struct seq_operations
argument and drastically reduces the boilerplate code in the callers.

All trivial callers converted over.

Signed-off-by: Christoph Hellwig <hch@lst.de>

The check for len > 0 is always true and hence is redundant as
this check is already being made to execute the code inside the
while-loop. Hence it is redundant and can be removed.

Cleans up cppcheck warning:
drivers/net/hamradio/mkiss.c:220: (warning) Identical inner 'if'
condition is always true.

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: David S. Miller <davem@davemloft.net>