Re: WARNING: can't access registers at asm_common_interrupt

[Shinichiro Kawasaki]

On Nov 06, 2020 / 12:06, Josh Poimboeuf wrote:
> On Fri, Nov 06, 2020 at 06:04:15AM +0000, Shinichiro Kawasaki wrote:
> > Greetings,
> > 
> > I observe "WARNING: can't access registers at asm_common_interrupt+0x1e/0x40"
> > in my kernel test system repeatedly, which is printed by unwind_next_frame() in
> > "arch/x86/kernel/unwind_orc.c". Syzbot already reported that [1]. Similar
> > warning was reported and discussed [2], but I suppose the cause is not yet
> > clarified.
> > 
> > The warning was observed with v5.10-rc2 and older tags. I bisected and found
> > that the commit 044d0d6de9f5 ("lockdep: Only trace IRQ edges") in v5.9-rc3
> > triggered the warning. Reverting that from 5.10-rc2, the warning disappeared.
> > May I ask comment by expertise on CC how this commit can relate to the warning?
> > 
> > The test condition to reproduce the warning is rather unique (blktests,
> > dm-linear and ZNS device emulation by QEMU). If any action is suggested for
> > further analysis, I'm willing to take it with my test system.
> 
> Hi,
> 
> Thanks for reporting this issue.  This might be a different issue from
> [2].
> 
> Can you send me the arch/x86/entry/entry_64.o file from your build?

Hi Josh, thank you for your response. As a separated e-mail, I have sent the
entry_64.o only to your address, since I hesitate to send around the 76kb
attachment file to LKML. In case it does not reach to you, please let me know.

-- 
Best Regards,
Shin'ichiro Kawasaki