From: Andrew Morton <akpm@linux-foundation.org>
To: Jeongjun Park <aha310510@gmail.com>
Cc: Liam.Howlett@Oracle.com, brauner@kernel.org,
lorenzo.stoakes@oracle.com, willy@infradead.org,
davidlohr.bueso@hp.com, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] ipc: fix to protect IPCS lookups using RCU instead of semaphore
Date: Fri, 14 Feb 2025 15:21:28 -0800 [thread overview]
Message-ID: <20250214152128.61a1054b90d1a53eff9cf16b@linux-foundation.org> (raw)
In-Reply-To: <20250214180157.10288-1-aha310510@gmail.com>
On Sat, 15 Feb 2025 03:01:57 +0900 Jeongjun Park <aha310510@gmail.com> wrote:
> In shm_destroy_orphaned(), we are not performing updates to the IPCS and are
> only calling idr_for_each(), which can be protected by the RCU read-critical
> section.
>
> And if idr_for_each() is not protected by the RCU read-critical section,
> then when radix_tree_node_free() is called to free the struct radix_tree_node
> through call_rcu(), the node will be freed immediately, and when reading the
> next node in radix_tree_for_each_slot(), the memory that has already been
> freed may be read.
A use-after-free?
Is there any report of this occurring, or was this change a result of
code inspection? If the former, please share details (Link:,
Reported-by:, Closes:, etc).
> Therefore, I think it is appropriate to use RCU instead of semaphore to
> protect it.
next prev parent reply other threads:[~2025-02-14 23:21 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-02-14 18:01 [PATCH] ipc: fix to protect IPCS lookups using RCU instead of semaphore Jeongjun Park
2025-02-14 18:58 ` Matthew Wilcox
2025-02-14 23:21 ` Andrew Morton [this message]
2025-02-15 5:00 ` Jeongjun Park
2025-02-15 17:39 ` Matthew Wilcox
2025-02-19 10:07 ` Jeongjun Park
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