From: Russell King <linux@armlinux.org.uk>
To: Qi Xi <xiqi2@huawei.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org,
Yuanbin Xie <xieyuanbin1@huawei.com>,
Nanyong Sun <sunnanyong@huawei.com>
Subject: Re: [PATCH v3 2/2] ARM: mm: protect show_pte() in do_DataAbort() fallback path
Date: Fri, 26 Jun 2026 10:45:18 +0100 [thread overview]
Message-ID: <aj5KLv_eMRUYNhck@shell.armlinux.org.uk> (raw)
In-Reply-To: <20260626073048.3595106-3-xiqi2@huawei.com>
On Fri, Jun 26, 2026 at 03:30:48PM +0800, Qi Xi wrote:
> The do_DataAbort() fallback path handles FSR types not serviced by
> do_page_fault() (fsr_info entries with fn=do_bad). This path also
> calls show_pte() without holding mmap_read_lock, exposing it to
> the same use-after-free issue.
>
> Since do_DataAbort() is an exception entry point that can be reached
> from contexts where sleeping is not allowed, use mmap_read_trylock().
> If the lock cannot be acquired, the page table dump is skipped.
>
> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
> Suggested-by: Yuanbin Xie <xieyuanbin1@huawei.com>
> Signed-off-by: Qi Xi <xiqi2@huawei.com>
Same reason as patch 1. We can't take locks.
--
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
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next prev parent reply other threads:[~2026-06-26 9:45 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-06-26 7:30 [PATCH v3 0/2] ARM: mm: fix use-after-free in show_pte() Qi Xi
2026-06-26 7:30 ` [PATCH v3 1/2] ARM: mm: fix use-after-free in __do_user_fault() under CONFIG_DEBUG_USER Qi Xi
2026-06-26 9:44 ` Russell King
2026-06-27 1:39 ` Qi Xi
2026-06-26 7:30 ` [PATCH v3 2/2] ARM: mm: protect show_pte() in do_DataAbort() fallback path Qi Xi
2026-06-26 9:45 ` Russell King [this message]
2026-06-26 10:16 ` Xie Yuanbin
2026-06-26 12:37 ` Russell King
2026-06-27 1:22 ` Xie Yuanbin
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