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[91.159.24.186]) by smtp.gmail.com with ESMTPSA id 2adb3069b0e04-5a9164cb606sm4751429e87.63.2026.05.20.01.49.59 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 20 May 2026 01:49:59 -0700 (PDT) Message-ID: Date: Wed, 20 May 2026 11:49:21 +0300 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] mm/slab: fix probable issue of dentries registration under /sys/kernel/slab To: Hao Li Cc: Vlastimil Babka , Harry Yoo , Andrew Morton , Christoph Lameter , David Rientjes , Roman Gushchin , Hugh Dickins , linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20260520011019.1707010-1-vladimir.zapolskiy@linaro.org> From: Vladimir Zapolskiy In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Hi Hao, On 5/20/26 06:21, Hao Li wrote: > 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.. > you're totally right, __kmem_cache_create_args execution path should also be fixed, I'll send v2. Thank you for review! -- Best wishes, Vladimir