From: "Shi, Yang" <yang.shi@linaro.org>
To: Will Deacon <will.deacon@arm.com>
Cc: aryabinin@virtuozzo.com, Catalin.Marinas@arm.com,
linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linaro-kernel@lists.linaro.org
Subject: Re: [PATCH v2] arm64: disable kasan when accessing frame->fp in unwind_frame
Date: Tue, 9 Feb 2016 09:17:12 -0800 [thread overview]
Message-ID: <56BA1F18.2020103@linaro.org> (raw)
In-Reply-To: <20160209165414.GT22874@arm.com>
On 2/9/2016 8:54 AM, Will Deacon wrote:
> On Mon, Feb 08, 2016 at 09:13:09AM -0800, Yang Shi wrote:
>> When boot arm64 kernel with KASAN enabled, the below error is reported by
>> kasan:
>>
>> BUG: KASAN: out-of-bounds in unwind_frame+0xec/0x260 at addr ffffffc064d57ba0
>> Read of size 8 by task pidof/499
>> page:ffffffbdc39355c0 count:0 mapcount:0 mapping: (null) index:0x0
>> flags: 0x0()
>> page dumped because: kasan: bad access detected
>> CPU: 2 PID: 499 Comm: pidof Not tainted 4.5.0-rc1 #119
>> Hardware name: Freescale Layerscape 2085a RDB Board (DT)
>> Call trace:
>> [<ffffffc00008d078>] dump_backtrace+0x0/0x290
>> [<ffffffc00008d32c>] show_stack+0x24/0x30
>> [<ffffffc0006a981c>] dump_stack+0x8c/0xd8
>> [<ffffffc0002e4400>] kasan_report_error+0x558/0x588
>> [<ffffffc0002e4958>] kasan_report+0x60/0x70
>> [<ffffffc0002e3188>] __asan_load8+0x60/0x78
>> [<ffffffc00008c92c>] unwind_frame+0xec/0x260
>> [<ffffffc000087e60>] get_wchan+0x110/0x160
>> [<ffffffc0003b647c>] do_task_stat+0xb44/0xb68
>> [<ffffffc0003b7730>] proc_tgid_stat+0x40/0x50
>> [<ffffffc0003ac840>] proc_single_show+0x88/0xd8
>> [<ffffffc000345be8>] seq_read+0x370/0x770
>> [<ffffffc00030aba0>] __vfs_read+0xc8/0x1d8
>> [<ffffffc00030c0ec>] vfs_read+0x94/0x168
>> [<ffffffc00030d458>] SyS_read+0xb8/0x128
>> [<ffffffc000086530>] el0_svc_naked+0x24/0x28
>> Memory state around the buggy address:
>> ffffffc064d57a80: 00 00 00 00 00 00 00 00 f1 f1 f1 f1 00 00 f4 f4
>> ffffffc064d57b00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>>> ffffffc064d57b80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>> ^
>> ffffffc064d57c00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>> ffffffc064d57c80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>>
>> Since the shadow byte pointed by the report is 0, so it may mean it is just hit
>> oob in non-current task. So, disable the instrumentation to silence these
>> warnings.
>
> Curious, but how did you trigger this? I'm just trying to confirm that
> mainline is affected, but my machine boots happily with KASAN and STACKTRACE
> selected and I can cat /proc/self/{stack,stat} quite happily.
>
> What am I missing?
I'm using mainline 4.5-rc1 kernel with gcc 5.2. And, my rootfs is NFS
mounted.
Not sure if other kernel configs, i.e tracing stuff will have impact on
the trigger since I'm not using the defconfig.
Thanks,
Yang
>
> Will
>
next prev parent reply other threads:[~2016-02-09 17:17 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-08 17:13 [PATCH v2] arm64: disable kasan when accessing frame->fp in unwind_frame Yang Shi
2016-02-09 13:22 ` Will Deacon
2016-02-09 13:50 ` Andrey Ryabinin
2016-02-09 16:54 ` Will Deacon
2016-02-09 17:17 ` Shi, Yang [this message]
2016-02-09 17:23 ` Will Deacon
2016-02-09 17:31 ` Shi, Yang
2016-02-09 17:32 ` Shi, Yang
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=56BA1F18.2020103@linaro.org \
--to=yang.shi@linaro.org \
--cc=Catalin.Marinas@arm.com \
--cc=aryabinin@virtuozzo.com \
--cc=linaro-kernel@lists.linaro.org \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=will.deacon@arm.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).