Re: x86: warning in unwind_get_return_address

From: Dmitry Vyukov
Date: Tue Dec 27 2016 - 11:39:52 EST

On Thu, Dec 22, 2016 at 6:17 AM, Josh Poimboeuf <jpoimboe@xxxxxxxxxx> wrote:
> On Wed, Dec 21, 2016 at 01:46:36PM +0100, Andrey Konovalov wrote:
>> On Wed, Dec 21, 2016 at 12:36 AM, Josh Poimboeuf <jpoimboe@xxxxxxxxxx> wrote:
>> >
>> > Thanks. Looking at the stack trace, my guess is that an interrupt hit
>> > while running in generated BPF code, and the unwinder got confused
>> > because regs->ip points to the generated code. I may need to disable
>> > that warning until we figure out a better solution.
>> >
>> > Can you share your .config file?
>> Sure, attached.
> Ok, I was able to recreate with your config. The culprit was generated
> code, as I suspected, though it wasn't BPF, it was a kprobe (created by
> dccpprobe_init()).
> I'll make a patch to disable the warning.


I am also seeing the following warnings:

[ 281.889259] WARNING: kernel stack regs at ffff8801c29a7ea8 in
syz-executor8:1302 has bad 'bp' value ffff8801c29a7f28
[ 833.994878] WARNING: kernel stack regs at ffff8801c4e77ea8 in
syz-executor1:13094 has bad 'bp' value ffff8801c4e77f28

Can it also be caused by bpf/kprobe?