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From:   Shinichiro Kawasaki <shinichiro.kawasaki@wdc.com>
To:     Josh Poimboeuf <jpoimboe@redhat.com>
CC:     "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Nicholas Piggin <npiggin@gmail.com>,
        Damien Le Moal <Damien.LeMoal@wdc.com>
Subject: Re: WARNING: can't access registers at asm_common_interrupt
Thread-Topic: WARNING: can't access registers at asm_common_interrupt
Thread-Index: AQHWtAKoC1N6UC8gbUaAN5Wk5A+R6Km7ZxIAgAQhSIA=
Date:   Mon, 9 Nov 2020 09:10:38 +0000
Message-ID: <20201109091037.6upb63tclk4nhvl7@shindev.dhcp.fujisawa.hgst.com>
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On Nov 06, 2020 / 12:06, Josh Poimboeuf wrote:
> On Fri, Nov 06, 2020 at 06:04:15AM +0000, Shinichiro Kawasaki wrote:
> > Greetings,
> >=20
> > 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_fr=
ame() in
> > "arch/x86/kernel/unwind_orc.c". Syzbot already reported that [1]. Simil=
ar
> > warning was reported and discussed [2], but I suppose the cause is not =
yet
> > clarified.
> >=20
> > 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 disapp=
eared.
> > May I ask comment by expertise on CC how this commit can relate to the =
warning?
> >=20
> > 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.
>=20
> Hi,
>=20
> Thanks for reporting this issue.  This might be a different issue from
> [2].
>=20
> 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 th=
e
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 kn=
ow.

--=20
Best Regards,
Shin'ichiro Kawasaki=