WARNING: kernel stack frame pointer has bad value

[syzbot]

Hello,

syzbot hit the following crash on upstream commit
48023102b7078a6674516b1fe0d639669336049d (Fri Apr 13 23:55:41 2018 +0000)
Merge branch 'overlayfs-linus' of
git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs
syzbot dashboard link:
https://syzkaller.appspot.com/bug?extid=37035ccfa9a0a017ffcf

So far this crash happened 141 times on net-next, upstream.
C reproducer: https://syzkaller.appspot.com/x/repro.c?id=5871698234572800
syzkaller reproducer:
https://syzkaller.appspot.com/x/repro.syz?id=5086177975599104
Raw console output:
https://syzkaller.appspot.com/x/log.txt?id=5110926181138432
Kernel config:
https://syzkaller.appspot.com/x/.config?id=-8852471259444315113
compiler: gcc (GCC) 8.0.1 20180413 (experimental)

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+37035c...@syzkaller.appspotmail.com
It will help syzbot understand when the bug is fixed. See footer for
details.
If you forward the report, please keep this part and the footer.

00000000ed8ccbe7: 0000000000440169 (0x440169)
00000000469f2a79: 0000000000000033 (0x33)
000000004636639d: 0000000000000246 (0x246)
00000000aa65aef8: 00007ffead676158 (0x7ffead676158)
00000000e3ef297c: 000000000000002b (0x2b)
WARNING: kernel stack frame pointer at 000000004832711f in
syzkaller561281:4479 has bad value 000000006b4f8502
WARNING: kernel stack regs at 0000000089e11b3b in syzkaller561281:4479 has
bad 'bp' value 00000000f19a2a3b
random: crng init done


---
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[Dmitry Vyukov]

On Thu, Apr 19, 2018 at 5:57 PM, syzbot
<syzbot+37035c...@syzkaller.appspotmail.com> wrote:
> Hello,
>
> syzbot hit the following crash on upstream commit
> 48023102b7078a6674516b1fe0d639669336049d (Fri Apr 13 23:55:41 2018 +0000)
> Merge branch 'overlayfs-linus' of
> git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs
> syzbot dashboard link:
> https://syzkaller.appspot.com/bug?extid=37035ccfa9a0a017ffcf
>
> So far this crash happened 141 times on net-next, upstream.
> C reproducer: https://syzkaller.appspot.com/x/repro.c?id=5871698234572800
> syzkaller reproducer:
> https://syzkaller.appspot.com/x/repro.syz?id=5086177975599104
> Raw console output:
> https://syzkaller.appspot.com/x/log.txt?id=5110926181138432
> Kernel config:
> https://syzkaller.appspot.com/x/.config?id=-8852471259444315113
> compiler: gcc (GCC) 8.0.1 20180413 (experimental)

This seems to be related to keccakf_rndc, please see the "Raw console
output" link.
+crypto maintainers