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

[Daniel Borkmann]

On 02/20/2019 10:32 AM, syzbot wrote:
> Hello,
> 
> syzbot found the following crash on:
> 
> HEAD commit:ÂÂÂ abf446c90405 Add linux-next specific files for 20190220
> git tree:ÂÂÂÂÂÂ linux-next
> console output: https://syzkaller.appspot.com/x/log.txt?x=17f250d8c00000
> kernel config:Â https://syzkaller.appspot.com/x/.config?x=463cb576ac40e350
> dashboard link: https://syzkaller.appspot.com/bug?extid=8bf19ee2aa580de7a2a7
> compiler:ÂÂÂÂÂÂ gcc (GCC) 9.0.0 20181231 (experimental)
> 
> Unfortunately, I don't have any reproducer for this crash yet.
> 
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: syzbot+8bf19ee2aa580de7a2a7@xxxxxxxxxxxxxxxxxxxxxxxxx
> 
> BUG: assuming atomic context at kernel/seccomp.c:271
> in_atomic(): 0, irqs_disabled(): 0, pid: 12803, name: syz-executor.5
> no locks held by syz-executor.5/12803.
> CPU: 1 PID: 12803 Comm: syz-executor.5 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:
> Â__dump_stack lib/dump_stack.c:77 [inline]
> Âdump_stack+0x172/0x1f0 lib/dump_stack.c:113
> Â__cant_sleep kernel/sched/core.c:6218 [inline]
> Â__cant_sleep.cold+0xa3/0xbb kernel/sched/core.c:6195
> Âseccomp_run_filters kernel/seccomp.c:271 [inline]
> Â__seccomp_filter+0x12b/0x12b0 kernel/seccomp.c:801
> Â__secure_computing+0x101/0x360 kernel/seccomp.c:932
> Âsyscall_trace_enter+0x5bf/0xe10 arch/x86/entry/common.c:120
> Âdo_syscall_64+0x479/0x610 arch/x86/entry/common.c:280
> Âentry_SYSCALL_64_after_hwframe+0x49/0xbe

False positive; bpf-next only. Pushing this out in a bit: