kernel panic: stack is corrupted in pointer

[John Fastabend]

Dmitry Vyukov wrote:
> On Wed, Jul 17, 2019 at 10:58 AM syzbot
> <syzbot+79f5f028005a77ecb6bb at syzkaller.appspotmail.com> wrote:
> >
> > Hello,
> >
> > syzbot found the following crash on:
> >
> > HEAD commit:    1438cde7 Add linux-next specific files for 20190716
> > git tree:       linux-next
> > console output: https://syzkaller.appspot.com/x/log.txt?x=13988058600000
> > kernel config:  https://syzkaller.appspot.com/x/.config?x=3430a151e1452331
> > dashboard link: https://syzkaller.appspot.com/bug?extid=79f5f028005a77ecb6bb
> > compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
> > syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=111fc8afa00000
> 
> From the repro it looks like the same bpf stack overflow bug. +John
> We need to dup them onto some canonical report for this bug, or this
> becomes unmanageable.

Fixes in bpf tree should fix this. Hopefully, we will squash this once fixes
percolate up.

#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf.git

> 
> #syz dup: kernel panic: corrupted stack end in dput
> 
> > The bug was bisected to:
> >
> > commit 96a5d8d4915f3e241ebb48d5decdd110ab9c7dcf
> > Author: Leo Liu <leo.liu at amd.com>
> > Date:   Fri Jul 13 15:26:28 2018 +0000
> >
> >      drm/amdgpu: Make sure IB tests flushed after IP resume
> >
> > bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=14a46200600000
> > final crash:    https://syzkaller.appspot.com/x/report.txt?x=16a46200600000
> > console output: https://syzkaller.appspot.com/x/log.txt?x=12a46200600000
> >
> > IMPORTANT: if you fix the bug, please add the following tag to the commit:
> > Reported-by: syzbot+79f5f028005a77ecb6bb at syzkaller.appspotmail.com
> > Fixes: 96a5d8d4915f ("drm/amdgpu: Make sure IB tests flushed after IP
> > resume")
> >
> > Kernel panic - not syncing: stack-protector: Kernel stack is corrupted in:
> > pointer+0x702/0x750 lib/vsprintf.c:2187
> > Shutting down cpus with NMI
> > Kernel Offset: disabled
> >
> >
> > ---
> > This bug is generated by a bot. It may contain errors.
> > See https://goo.gl/tpsmEJ for more information about syzbot.
> > syzbot engineers can be reached at syzkaller at googlegroups.com.
> >
> > syzbot will keep track of this bug report. See:
> > https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
> > For information about bisection process see: https://goo.gl/tpsmEJ#bisection
> > syzbot can test patches for this bug, for details see:
> > https://goo.gl/tpsmEJ#testing-patches