From: "David Hildenbrand (Arm)" <david@kernel.org>
To: sparkhuang <huangshaobo3@xiaomi.com>
Cc: akpm@linux-foundation.org, bsegall@google.com,
dietmar.eggemann@arm.com, juri.lelli@redhat.com, kees@kernel.org,
kprateek.nayak@amd.com, liam@infradead.org,
linux-kernel@vger.kernel.org, linux-mm@kvack.org, ljs@kernel.org,
mgorman@suse.de, mhocko@suse.com, mingo@redhat.com,
peterz@infradead.org, rostedt@goodmis.org, rppt@kernel.org,
ryabinin.a.a@gmail.com, stable@vger.kernel.org,
surenb@google.com, vbabka@kernel.org, vincent.guittot@linaro.org,
vschneid@redhat.com
Subject: Re: [PATCH] fork: reset pointer tag of vmapped thread stack before vfree
Date: Fri, 7 Aug 2026 12:47:59 +0200 [thread overview]
Message-ID: <682b2569-0a20-4595-b83b-8c833c387baf@kernel.org> (raw)
In-Reply-To: <20260807104153.94261-1-huangshaobo3@xiaomi.com>
On 8/7/26 12:41, sparkhuang wrote:
> On 2026-08-07 9:27 UTC, David wrote:
>> Were you able to reproduce this more than once?
>
> Still trying to reproduce it. So far it has only occurred this once.
>
>> Does this relate to CONFIG_KASAN_STACK?
>
> I'm not entirely sure if it's related.
> The configs relevant to this path are:
> CONFIG_KASAN_SHADOW_OFFSET=0xefffffc000000000
> CONFIG_HAVE_ARCH_KASAN=y
> CONFIG_HAVE_ARCH_KASAN_SW_TAGS=y
> CONFIG_HAVE_ARCH_KASAN_HW_TAGS=y
> CONFIG_HAVE_ARCH_KASAN_VMALLOC=y
> CONFIG_CC_HAS_KASAN_GENERIC=y
> CONFIG_CC_HAS_KASAN_SW_TAGS=y
> CONFIG_KASAN=y
> CONFIG_CC_HAS_KASAN_MEMINTRINSIC_PREFIX=y
> # CONFIG_KASAN_GENERIC is not set
> CONFIG_KASAN_SW_TAGS=y
> # CONFIG_KASAN_HW_TAGS is not set
> CONFIG_KASAN_OUTLINE=y
> # CONFIG_KASAN_INLINE is not set
> CONFIG_KASAN_STACK=y
The KASAN_STACK might be the relevant bit. We will get the stack retagged, so
when we free the memory, the stored tag and the memory tag will differ.
At least that's my understanding from a quick peek :)
--
Cheers,
David
next prev parent reply other threads:[~2026-08-07 10:48 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-06 12:30 [PATCH] fork: reset pointer tag of vmapped thread stack before vfree sparkhuang
2026-08-06 14:13 ` Lorenzo Stoakes (ARM)
2026-08-07 6:53 ` sparkhuang
2026-08-07 7:56 ` Lorenzo Stoakes (ARM)
2026-08-07 7:57 ` David Hildenbrand (Arm)
2026-08-07 7:58 ` Lorenzo Stoakes (ARM)
2026-08-07 8:00 ` David Hildenbrand (Arm)
2026-08-07 9:27 ` David Hildenbrand (Arm)
2026-08-07 10:41 ` sparkhuang
2026-08-07 10:47 ` David Hildenbrand (Arm) [this message]
2026-08-07 11:20 ` David Hildenbrand (Arm)
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=682b2569-0a20-4595-b83b-8c833c387baf@kernel.org \
--to=david@kernel.org \
--cc=akpm@linux-foundation.org \
--cc=bsegall@google.com \
--cc=dietmar.eggemann@arm.com \
--cc=huangshaobo3@xiaomi.com \
--cc=juri.lelli@redhat.com \
--cc=kees@kernel.org \
--cc=kprateek.nayak@amd.com \
--cc=liam@infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=ljs@kernel.org \
--cc=mgorman@suse.de \
--cc=mhocko@suse.com \
--cc=mingo@redhat.com \
--cc=peterz@infradead.org \
--cc=rostedt@goodmis.org \
--cc=rppt@kernel.org \
--cc=ryabinin.a.a@gmail.com \
--cc=stable@vger.kernel.org \
--cc=surenb@google.com \
--cc=vbabka@kernel.org \
--cc=vincent.guittot@linaro.org \
--cc=vschneid@redhat.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