Re: WARNING in set_restore_sigmask

[Andrew Morton]

On Fri, 29 Jan 2016 15:13:47 +0100 Oleg Nesterov <oleg@xxxxxxxxxx> wrote:

> On 01/29, Dmitry Vyukov wrote:
> >
> > Hello,
> >
> > I've got the following WARNING while running syzkaller fuzzer:
> >
> > ------------[ cut here ]------------
> > WARNING: CPU: 2 PID: 10905 at ./arch/x86/include/asm/thread_info.h:236
> > sigsuspend+0x18e/0x1f0()
> > Modules linked in:
> > CPU: 2 PID: 10905 Comm: syz-executor Not tainted 4.5.0-rc1+ #300
> > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
> >  00000000ffffffff ffff88006139fe38 ffffffff82be118d 0000000000000000
> >  ffff88006d054740 ffffffff867387e0 ffff88006139fe78 ffffffff813536d9
> >  ffffffff813839ce ffffffff867387e0 00000000000000ec 0000000020000000
> > Call Trace:
> >  [<     inline     >] __dump_stack lib/dump_stack.c:15
> >  [<ffffffff82be118d>] dump_stack+0x6f/0xa2 lib/dump_stack.c:50
> >  [<ffffffff813536d9>] warn_slowpath_common+0xd9/0x140 kernel/panic.c:482
> >  [<ffffffff81353909>] warn_slowpath_null+0x29/0x30 kernel/panic.c:515
> >  [<     inline     >] set_restore_sigmask
> > ./arch/x86/include/asm/thread_info.h:236
> >  [<ffffffff813839ce>] sigsuspend+0x18e/0x1f0 kernel/signal.c:3513
> 
> See http://marc.info/?t=145373722000004 the patch is already in -mm tree.

I'll get this into 4.5 as we now appear to have some code which actually
triggers it.

I wonder where that wakeup is coming from.