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From: Hao Li To: Vladimir Zapolskiy Cc: Vlastimil Babka , Harry Yoo , Andrew Morton , Christoph Lameter , David Rientjes , Roman Gushchin , Hugh Dickins , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm/slab: fix probable issue of dentries registration under /sys/kernel/slab Message-ID: References: <20260520011019.1707010-1-vladimir.zapolskiy@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260520011019.1707010-1-vladimir.zapolskiy@linaro.org> X-Migadu-Flow: FLOW_OUT X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: F22051C0004 X-Rspam-User: X-Stat-Signature: 6u7g7eoa7kz1fs4r988p3nyf811zi3xe X-HE-Tag: 1779247293-763209 X-HE-Meta: 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 KbqGA6cr 0jVaAR84SGF+OQQ4nIfYsNQjFVi8/980WsUQeeG581qgvdb9qPwD8G21p6pp5NVOHBHnatrLxMkiGooeuCbK//vJH+fIzSvxJz9Jo4bu1EifzpwODmwYW3i1sTBe36APQUI411hFihiiVrKEJFF9JpZVPTF9VSxIE8AU8Fpk+SDtHpxCW3e0cJyYZlVBvGw9OOI2v/7XlpK1/xp0= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Wed, May 20, 2026 at 04:10:19AM +0300, Vladimir Zapolskiy wrote: > L2TP/IP and L2TP/IPv6 protocol names contain a slash symbol, however these > names are blindly used as symlinks to slab cache objects registered under > /sys/kernel/slab. This kind of symlink creation is successful, but its > dentry is obviously broken, as well it breaks the access to the list of > /sys/kernel/slab dentries. > > Likely L2TP protocol renames cannot be done, since the defined protocol > names are exposed over /proc/net/protocols for years, but the symlink > names can be renamed, because they are yet to be properly created, and > this should be eventually done by this change. > > The problem manifests itself, if CONFIG_L2TP_IP build symbol is selected. Hello, thanks for the patch. Could L2TP possibly be loaded as a module? I noticed that __kmem_cache_create_args can also call into sysfs_slab_alias. If L2TP is loaded as a module after boot and dynamically creates a slub cache, it may bypass your fix.. -- Thanks, Hao