From: Naresh Kamboju <naresh.kamboju@linaro.org>
To: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Will Deacon <will@kernel.org>,
rcu@vger.kernel.org, open list <linux-kernel@vger.kernel.org>,
Linux-Next Mailing List <linux-next@vger.kernel.org>,
lkft-triage@lists.linaro.org,
Peter Zijlstra <peterz@infradead.org>,
Steven Rostedt <rostedt@goodmis.org>,
Ingo Molnar <mingo@kernel.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Linux ARM <linux-arm-kernel@lists.infradead.org>,
Vincenzo Frascino <vincenzo.frascino@arm.com>,
Mark Rutland <mark.rutland@arm.com>
Subject: Re: rcu-torture: Internal error: Oops: 96000006
Date: Fri, 22 Jan 2021 15:21:07 +0530 [thread overview]
Message-ID: <CA+G9fYvZ5oE2bAkZqTYE87N0ONWoo2Q6VZBXihu4NQ_+C07qgA@mail.gmail.com> (raw)
In-Reply-To: <20210121214314.GW2743@paulmck-ThinkPad-P72>
On Fri, 22 Jan 2021 at 03:13, Paul E. McKenney <paulmck@kernel.org> wrote:
>
> On Thu, Jan 21, 2021 at 09:31:10PM +0000, Will Deacon wrote:
> > On Thu, Jan 21, 2021 at 10:55:21AM -0800, Paul E. McKenney wrote:
> > > On Thu, Jan 21, 2021 at 10:37:21PM +0530, Naresh Kamboju wrote:
> > > > While running rcu-torture test on qemu_arm64 and arm64 Juno-r2 device
> > > > the following kernel crash noticed. This started happening from Linux next
> > > > next-20210111 tag to next-20210121.
> > > >
> > > > metadata:
> > > > git branch: master
> > > > git repo: https://gitlab.com/Linaro/lkft/mirrors/next/linux-next
> > > > git describe: next-20210111
> > > > kernel-config: https://builds.tuxbuild.com/1muTTn7AfqcWvH5x2Alxifn7EUH/config
> > > >
> > > > output log:
> > > >
> > > > [ 621.538050] mem_dump_obj() slab test: rcu_torture_stats =
> > > > ffff0000c0a3ac40, &rhp = ffff800012debe40, rhp = ffff0000c8cba000, &z
> > > > = ffff8000091ab8e0
> > > > [ 621.546662] mem_dump_obj(ZERO_SIZE_PTR):
> > > > [ 621.546696] Unable to handle kernel NULL pointer dereference at
> > > > virtual address 0000000000000008
> >
> > [...]
> >
> > > Huh. I am relying on virt_addr_valid() rejecting NULL pointers and
> > > things like ZERO_SIZE_PTR, which is defined as ((void *)16). It looks
> > > like your configuration rejects NULL as an invalid virtual address,
> > > but does not reject ZERO_SIZE_PTR. Is this the intent, given that you
> > > are not allowed to dereference a ZERO_SIZE_PTR?
> > >
> > > Adding the ARM64 guys on CC for their thoughts.
> >
> > Spooky timing, there was a thread _today_ about that:
> >
> > https://lore.kernel.org/r/ecbc7651-82c4-6518-d4a9-dbdbdf833b5b@arm.com
>
> Very good, then my workaround (shown below for Naresh's ease of testing)
> is only a short-term workaround. Yay! ;-)
Paul, thanks for your (short-term workaround) patch.
I have applied your patch and tested rcu-torture test on qemu_arm64 and
the reported issues has been fixed.
- Naresh
next prev parent reply other threads:[~2021-01-22 10:04 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-21 17:07 rcu-torture: Internal error: Oops: 96000006 Naresh Kamboju
2021-01-21 18:55 ` Paul E. McKenney
2021-01-21 21:31 ` Will Deacon
2021-01-21 21:43 ` Paul E. McKenney
2021-01-22 9:51 ` Naresh Kamboju [this message]
2021-01-22 15:37 ` Paul E. McKenney
2021-01-22 15:46 ` Naresh Kamboju
2021-01-22 23:23 ` Paul E. McKenney
2021-01-22 10:02 ` Mark Rutland
2021-01-22 11:45 ` Vincenzo Frascino
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