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Wysocki" , Danilo Krummrich , driver-core@lists.linux.dev, Pedro Falcato References: <20260520011019.1707010-1-vladimir.zapolskiy@linaro.org> <8a80496b-1568-4a0b-a878-836c27d19ad5@kernel.org> <08d70e06-f392-4c36-8396-735ac70ef82c@kernel.org> Content-Language: en-US In-Reply-To: <08d70e06-f392-4c36-8396-735ac70ef82c@kernel.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Stat-Signature: akpiq1pun4b471stj1m887qutq41s5gs X-Rspamd-Queue-Id: EE1BA100006 X-Rspamd-Server: rspam07 X-Rspam-User: X-HE-Tag: 1779415896-856477 X-HE-Meta: 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 lfwhoail 7VXGE0+ndLDppCk3BrjVQWx/BQQvP6RXaap8Sqa5t5JzPz1AAFq8OuVQ5ozLxpr8yVfqQK3uBgjrosG2kbF6NB6h1vHgBZif2ted9PLn1p14qSrC2lGTdg4+Lo6UgEFijkf4+heuyLs2wk6aGkyaV7EO0Nii854TUxMSadQ+CRsTWDmSVz3cPT90N70MxBW1YRJHXsdUHt/Ixbg13RQClkaq/a1y0ISI7N8Y2MW5T3fnZg5oJJj3Eb7ee9ONLhdO1aZBYYUXC6lQ+hkgSJR4vJZTWuuE27J1N4vUptlOks6q8vNIbvpH+R61RZlSGfAuKtQzGLTAWto1ZTKE+tqCMHiUbCw== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 5/22/26 10:31 AM, Harry Yoo wrote: > > > On 5/21/26 8:24 PM, Vladimir Zapolskiy wrote: >> Harry, >> >> On 5/20/26 06:42, Harry Yoo wrote: >>> >>> >>> On 5/20/26 10:10 AM, 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. >>> >>> Oops. I just loaded l2tp_ip module and it indeed broke it. >>> >>> $ ls >>> ls: reading directory '.': Input/output error >>> :0000136/                        kmalloc-rnd-01-16/   kmalloc-rnd-15-32/ >>> :0000192/                        kmalloc-rnd-02-512/  memdup_user-32/ >>> :0000560/                        kmalloc-rnd-06-192/  memdup_user-4k/ >>> :0000768/                        kmalloc-rnd-06-512/  pde_opener@ >>> :a-0000168/                      kmalloc-rnd-07-4k/   pidfs_xattr_cache@ >>> :A-0000184/                      kmalloc-rnd-11-8/    RAWv6/ >>> audit_buffer@                    kmalloc-rnd-11-96/   rpc_inode_cache/ >>> configfs_dir_cache@              kmalloc-rnd-12-4k/   task_delay_info@ >>> ecryptfs_global_auth_tok_cache@  kmalloc-rnd-13-128/  TCPv6/ >>> fscache_cookie_jar@              kmalloc-rnd-14-96/ >>> io_kiocb/                        kmalloc-rnd-15-2k/ >>> >>>> 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. >>>> >>>> Fixes: 81819f0fc8285 ("SLUB core") >>>> Signed-off-by: Vladimir Zapolskiy >>>> --- >>> >>> There is also a debugfs feature that would cause a similar issue. >> >> thank you for review, I've just sent v2 fixing __kmem_cache_create_args() >> side. As for debugfs I haven't reproduced any similar issue, please give >> me a clue here, also likely any non-slab changes should be done >> separately. > > Ah, nevermind! I totally misread the patch. > I thought it only addresses the symlink name. Oh wait, no. I did not misread v1. I meant debugfs_slab_add() creates a directory under /sys/kernel/debug/slab/ based on s->name, so sysfs is not only thing that's broken :) So I think we should either reject '/' in s->name or replace it with another character, or let sysfs/kernfs handle it (as replied on v2) -- Cheers, Harry / Hyeonggon