Re: WARNING in syscall_exit_to_user_mode

[Kees Cook]

On Fri, Sep 11, 2020 at 03:39:19AM -0700, syzbot wrote:
> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    f4d51dff Linux 5.9-rc4
> git tree:       upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=12a4e7cd900000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=a9075b36a6ae26c9
> dashboard link: https://syzkaller.appspot.com/bug?extid=7ffc7214b893651d52b8
> compiler:       gcc (GCC) 10.1.0-syz 20200507
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=122d7335900000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=13cea1a5900000
> 
> Bisection is inconclusive: the issue happens on the oldest tested release.
> 
> bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=162247cd900000
> final oops:     https://syzkaller.appspot.com/x/report.txt?x=152247cd900000
> console output: https://syzkaller.appspot.com/x/log.txt?x=112247cd900000
> 
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+7ffc7214b893651d52b8@xxxxxxxxxxxxxxxxxxxxxxxxx
> 
> ------------[ cut here ]------------
> syscall 56 left IRQs disabled

This WARN appears reachable. :)

I also see on the dashboard these other problems with the new entry
code:

https://syzkaller.appspot.com/bug?extid=d4336c84ed0099fdbe47
https://syzkaller.appspot.com/bug?extid=c4af95386364bc59b13e

I can't tell if any of these have been looked at yet, though.

-- 
Kees Cook