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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 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 X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 0D15FA000A X-Stat-Signature: x97gp6k6efyegjy7w4gqdojikjih3mar X-Rspam-User: X-HE-Tag: 1779267001-944149 X-HE-Meta: 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 PaUo4SdV hI3b7tOEGPq70dWibVSeCbkQcl9lUM+1OVLvF++xF2IgC79E7oqzIMiETJ+5vYFt+ASC4Rlfgxc1Anb407EsU2eYM88jPSTPh2Cn+e1jUcO88pCnBXuRkzOdUOV7wS48eQlKVNoh3t9H94srZ1e5J2KVX+BDHzlBmEKGGli/6BmQWPV+eIMWx7sL1C7nNbv7w4v8bNzJGXmUw83mnqPYyPxzTo1UaGMOcs13hmb7hdy6gZlGPg4an36+Gq/EidrFFHqeRQZAG0xGxIXzzv7orp4PiaC7IS43FaLUL64fXo2rFa9Rup4guDhKtbJEHgB+MOz31 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 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