Re: WARNING in rcu_note_context_switch

[Peter Zijlstra]

On Tue, Oct 01, 2019 at 01:09:07AM -0700, syzbot wrote:
> Hello,
> 
> syzbot found the following crash on:
> 
> HEAD commit:    54ecb8f7 Linux 5.4-rc1
> git tree:       upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=14972bf3600000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=fb0b431ccdf08c1c
> dashboard link: https://syzkaller.appspot.com/bug?extid=0e1a9dce275f13907b4e
> compiler:       clang version 9.0.0 (/home/glider/llvm/clang
> 80fee25776c2fb61e74c1ecb1a523375c2500b69)
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=16875a35600000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=104bd519600000
> 
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: syzbot+0e1a9dce275f13907b4e@xxxxxxxxxxxxxxxxxxxxxxxxx
> 
> ------------[ cut here ]------------
> WARNING: CPU: 1 PID: 7994 at kernel/rcu/tree_plugin.h:293
> rcu_note_context_switch+0xdde/0xee0 kernel/rcu/tree_plugin.h:293
> Kernel panic - not syncing: panic_on_warn set ...

https://lkml.kernel.org/r/20191001071921.GJ4519@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx