Re: BUG: unable to handle kernel NULL pointer dereference in handle_external_interrupt_irqoff

[Dmitry Vyukov]

On Sun, Mar 22, 2020 at 2:29 PM syzbot
<syzbot+3f29ca2efb056a761e38@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
>
> syzbot has bisected this bug to:
>
> commit f71dbf2fb28489a79bde0dca1c8adfb9cdb20a6b
> Author: David Howells <dhowells@xxxxxxxxxx>
> Date:   Thu Jan 30 21:50:36 2020 +0000
>
>     rxrpc: Fix insufficient receive notification generation

This is unrelated.
Somehow the crash wasn't reproduced again on the same commit. Can it
depend on host CPU type maybe?

> bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=1483bb19e00000
> start commit:   b74b991f Merge tag 'block-5.6-20200320' of git://git.kerne..
> git tree:       upstream
> final crash:    https://syzkaller.appspot.com/x/report.txt?x=1683bb19e00000
> console output: https://syzkaller.appspot.com/x/log.txt?x=1283bb19e00000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=6dfa02302d6db985
> dashboard link: https://syzkaller.appspot.com/bug?extid=3f29ca2efb056a761e38
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1199c0c5e00000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=15097373e00000
>
> Reported-by: syzbot+3f29ca2efb056a761e38@xxxxxxxxxxxxxxxxxxxxxxxxx
> Fixes: f71dbf2fb284 ("rxrpc: Fix insufficient receive notification generation")
>
> For information about bisection process see: https://goo.gl/tpsmEJ#bisection