From: Breno Leitao <leitao@debian.org>
To: Yuichiro Goto <goto@k-tech.co.jp>
Cc: a.hindborg@kernel.org, viro@zeniv.linux.org.uk,
linux-kernel@vger.kernel.org, stable@vger.kernel.org
Subject: Re: [PATCH] configfs: wait for pending RCU callbacks on module exit
Date: Fri, 13 Nov 2026 03:33:14 -0800 [thread overview]
Message-ID: <avb1CyLqJGI_MtXv@gmail.com> (raw)
In-Reply-To: <20261113033833.124797-1-goto@k-tech.co.jp>
On Fri, Nov 13, 2026 at 12:38:33PM +0900, Yuichiro Goto wrote:
> configfs inodes are freed from an RCU callback: destroy_inode() queues
> i_callback() with call_rcu(), and i_callback() then calls the
> ->free_inode() of the super block, configfs_free_inode(). Nothing in
> configfs_exit() waits for these callbacks, so the module can go away
> while some of them are still pending, and they later jump into freed
> module text.
Is this still the case on mainline? Since commit 3bc999d944b3 ("mm/slab:
introduce kfree_rcu_nolock()") in v7.3, kmem_cache_destroy() calls
rcu_barrier() unconditionally, and configfs_exit() already reaches it:
configfs_exit()
kmem_cache_destroy(configfs_dir_cachep)
kvfree_rcu_barrier_on_cache()
rcu_barrier()
so the pending configfs_free_inode() calls finish before configfs_exit()
returns.
prev parent reply other threads:[~2026-11-13 11:33 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-11-13 3:38 [PATCH] configfs: wait for pending RCU callbacks on module exit Yuichiro Goto
2026-11-13 11:33 ` Breno Leitao [this message]
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