Subject: Re: BUG: assuming atomic context at kernel/seccomp.c:LINE

From: syzbot <[email-masked]>
Date: Wed, 20 Feb 2019 04:33:03 -0800

syzbot has found a reproducer for the following crash on:

HEAD commit:    abf446c90405 Add linux-next specific files for 20190220
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=101e7fb0c00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=463cb576ac40e350
dashboard link: https://syzkaller.appspot.com/bug?extid=8bf19ee2aa580de7a2a7
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=11a52778c00000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=12a1007cc00000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: [email-masked]

BUG: assuming atomic context at kernel/seccomp.c:271
in_atomic(): 0, irqs_disabled(): 0, pid: 7853, name: syz-executor140
no locks held by syz-executor140/7853.
CPU: 1 PID: 7853 Comm: syz-executor140 Not tainted 5.0.0-rc7-next-20190220  
#39
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
Call Trace:
  __dump_stack lib/dump_stack.c:77 [inline]
  dump_stack+0x172/0x1f0 lib/dump_stack.c:113
  __cant_sleep kernel/sched/core.c:6218 [inline]
  __cant_sleep.cold+0xa3/0xbb kernel/sched/core.c:6195
  seccomp_run_filters kernel/seccomp.c:271 [inline]
  __seccomp_filter+0x12b/0x12b0 kernel/seccomp.c:801
  __secure_computing+0x101/0x360 kernel/seccomp.c:932
  syscall_trace_enter+0x5bf/0xe10 arch/x86/entry/common.c:120
  do_syscall_64+0x479/0x610 arch/x86/entry/common.c:280
  entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x43ec58
Code: 00 00 be 3c 00 00 00 eb 19 66 0f 1f 84 00 00 00 00 00 48 89 d7 89 f0  
0f 05 48 3d 00 f0 ff ff 77 21 f4 48 89 d7 44 89 c0 0f 05 <48> 3d 00 f0 ff  
ff 76 e0 f7 d8 64 41 89 01 eb d8 0f 1f 84 00 00 00
RSP: 002b:00007ffc2d0b2f48 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043ec58
RDX: 0000000000000000 RSI: 0000000