Linux Ethernet Bridging - Apr 2019 - [Bridge] WARNING in compat_copy_entries (2)

syzbot has bisected this bug to:

commit 9dea5dc921b5f4045a18c63eb92e84dc274d17eb
Author: Andy Lutomirski <luto at kernel.org>
Date:   Tue Jul 14 22:24:24 2015 +0000

     x86/entry/syscalls: Wire up 32-bit direct socket calls

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=1736919f200000
start commit:   ce380619 Merge tag 'please-pull-ia64_misc' of
git://git.ke..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=10b6919f200000
kernel config:  https://syzkaller.appspot.com/x/.config?x=36fbc8c97ef985d3
dashboard link: https://syzkaller.appspot.com/bug?extid=659574e7bcc7f7eb4df7
userspace arch: i386
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=179b4d8b800000

Reported-by: syzbot+659574e7bcc7f7eb4df7 at syzkaller.appspotmail.com
Fixes: 9dea5dc921b5 ("x86/entry/syscalls: Wire up 32-bit direct socket  
calls")

For information about bisection process see: https://goo.gl/tpsmEJ#bisection

This is likely a confused bisection.  I bet that reverting this patch breaks
your test but has nothing to do with the bug. Try reproducing with socketcall()
to bisect farther.

--Andy
> On Apr 14, 2019, at 12:20 PM, syzbot <syzbot+659574e7bcc7f7eb4df7 at
syzkaller.appspotmail.com> wrote:
> 
> syzbot has bisected this bug to:
> 
> commit 9dea5dc921b5f4045a18c63eb92e84dc274d17eb
> Author: Andy Lutomirski <luto at kernel.org>
> Date:   Tue Jul 14 22:24:24 2015 +0000
> 
>    x86/entry/syscalls: Wire up 32-bit direct socket calls
> 
> bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=1736919f200000
> start commit:   ce380619 Merge tag 'please-pull-ia64_misc' of
git://git.ke..
> git tree:       upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=10b6919f200000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=36fbc8c97ef985d3
> dashboard link:
https://syzkaller.appspot.com/bug?extid=659574e7bcc7f7eb4df7
> userspace arch: i386
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=179b4d8b800000
> 
> Reported-by: syzbot+659574e7bcc7f7eb4df7 at syzkaller.appspotmail.com
> Fixes: 9dea5dc921b5 ("x86/entry/syscalls: Wire up 32-bit direct socket
calls")
> 
> For information about bisection process see:
https://goo.gl/tpsmEJ#bisection

Andy Lutomirski <luto at amacapital.net> wrote:
> This is likely a confused bisection.  I bet that reverting this patch
breaks your test but has nothing to do with the bug. Try reproducing with
socketcall() to bisect farther.
No need, this WARN_ON can be removed. I'll send a patch.