Andrey reported this kernel warning:

  WARNING: CPU: 0 PID: 4608 at kernel/sched/core.c:7724
  __might_sleep+0x14c/0x1a0 kernel/sched/core.c:7719
  do not call blocking ops when !TASK_RUNNING; state=1 set at
  [<ffffffff811f5a5c>] prepare_to_wait+0xbc/0x210
  kernel/sched/wait.c:178
  Modules linked in:
  CPU: 0 PID: 4608 Comm: syz-executor Not tainted 4.9.0-rc2+ #320
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
   ffff88006625f7a0 ffffffff81b46914 ffff88006625f818 0000000000000000
   ffffffff84052960 0000000000000000 ffff88006625f7e8 ffffffff81111237
   ffff88006aceac00 ffffffff00001e2c ffffed000cc4beff ffffffff84052960
  Call Trace:
   [<     inline     >] __dump_stack lib/dump_stack.c:15
   [<ffffffff81b46914>] dump_stack+0xb3/0x10f lib/dump_stack.c:51
   [<ffffffff81111237>] __warn+0x1a7/0x1f0 kernel/panic.c:550
   [<ffffffff8111132c>] warn_slowpath_fmt+0xac/0xd0 kernel/panic.c:565
   [<ffffffff811922fc>] __might_sleep+0x14c/0x1a0 kernel/sched/core.c:7719
   [<     inline     >] slab_pre_alloc_hook mm/slab.h:393
   [<     inline     >] slab_alloc_node mm/slub.c:2634
   [<     inline     >] slab_alloc mm/slub.c:2716
   [<ffffffff81508da0>] __kmalloc_track_caller+0x150/0x2a0 mm/slub.c:4240
   [<ffffffff8146be14>] kmemdup+0x24/0x50 mm/util.c:113
   [<ffffffff8388b2cf>] dccp_feat_clone_sp_val.part.5+0x4f/0xe0 net/dccp/feat.c:374
   [<     inline     >] dccp_feat_clone_sp_val net/dccp/feat.c:1141
   [<     inline     >] dccp_feat_change_recv net/dccp/feat.c:1141
   [<ffffffff8388d491>] dccp_feat_parse_options+0xaa1/0x13d0 net/dccp/feat.c:1411
   [<ffffffff83894f01>] dccp_parse_options+0x721/0x1010 net/dccp/options.c:128
   [<ffffffff83891280>] dccp_rcv_state_process+0x200/0x15b0 net/dccp/input.c:644
   [<ffffffff838b8a94>] dccp_v4_do_rcv+0xf4/0x1a0 net/dccp/ipv4.c:681
   [<     inline     >] sk_backlog_rcv ./include/net/sock.h:872
   [<ffffffff82b7ceb6>] __release_sock+0x126/0x3a0 net/core/sock.c:2044
   [<ffffffff82b7d189>] release_sock+0x59/0x1c0 net/core/sock.c:2502
   [<     inline     >] inet_wait_for_connect net/ipv4/af_inet.c:547
   [<ffffffff8316b2a2>] __inet_stream_connect+0x5d2/0xbb0 net/ipv4/af_inet.c:617
   [<ffffffff8316b8d5>] inet_stream_connect+0x55/0xa0 net/ipv4/af_inet.c:656
   [<ffffffff82b705e4>] SYSC_connect+0x244/0x2f0 net/socket.c:1533
   [<ffffffff82b72dd4>] SyS_connect+0x24/0x30 net/socket.c:1514
   [<ffffffff83fbf701>] entry_SYSCALL_64_fastpath+0x1f/0xc2
  arch/x86/entry/entry_64.S:209

Unlike commit 26cabd31
("sched, net: Clean up sk_wait_event() vs. might_sleep()"), the
sleeping function is called before schedule_timeout(), this is indeed
a bug. Fix this by moving the wait logic to the new API, it is similar
to commit ff960a73


("netdev, sched/wait: Fix sleeping inside wait event").

Reported-by: Andrey Konovalov <andreyknvl@google.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>