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b=bo+TymvpxxRc2c3hAxES9XbNbQqulQYx1SsCVi28ZwWJLt7AFPjcGIX9mbNoBkJ65 jDahOBbTgwf17xQ4MB/Paf0qi84pSEdTOsZU03OVY+Mo76vLIlYJzMofh0I4bQF2h3 LTFJ6sQzuBR5IuaobyoHBIQLudhDWvyRUaxN783YjdX7bWIUmjqAcw+UloBJNWpprc t/6aZNUqUZTX7TsETyB5gt4XVB3sUmwOsaaNu/kOtJ8waFsyKw0wgl2Hm0ER40ncaG GGVUd//wgrYXjnuHbZx1++O21swJtbbqoEcau3lj8WW9wCEFFQ2EZUSKuNbTLgofRW O7u+xQN4j/MLg== Date: Wed, 5 Jun 2024 20:54:33 +0100 From: Simon Horman To: Kees Cook Cc: Tycho Andersen , Vlastimil Babka , Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , jvoisin , Andrew Morton , Roman Gushchin , Hyeonggon Yoo <42.hyeyoo@gmail.com>, linux-mm@kvack.org, "GONG, Ruiqi" , Xiu Jianfeng , Suren Baghdasaryan , Kent Overstreet , Jann Horn , Matteo Rizzo , Thomas Graf , Herbert Xu , linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org, netdev@vger.kernel.org Subject: Re: [PATCH v4 4/6] mm/slab: Introduce kmem_buckets_create() and family Message-ID: <20240605195433.GA791188@kernel.org> References: <20240531191304.it.853-kees@kernel.org> <20240531191458.987345-4-kees@kernel.org> <20240604150228.GS491852@kernel.org> <202406041749.27CAE270@keescook> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <202406041749.27CAE270@keescook> X-Rspamd-Queue-Id: 5F8CB40009 X-Stat-Signature: 31mamtronjgigychekgb7pw7zfaoezig X-Rspam-User: X-Rspamd-Server: rspam11 X-HE-Tag: 1717617286-225633 X-HE-Meta: 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 gf0DiylX Oj3JGJyQyAGurYZYfA8QekVgjrEbGuLZY+y4/MCugnz/2StJxVUZ5W3eEy9BLdQ3P8LVrct1dCilrwWPq3s2KzYoq7tX8utBEfjS0p92r8TBGBpwWuvmzDmu3QtB9rWZvStmNqs6dcdBEppgWFSH9tI12x4oB1yVCnmEZKdlTMv50kmqxXRYDbPPCKECXiRunqka8WuSjAWWGU3nKvIn+BN4Eg4D8IQmNRwS3AdXwkVTdbDJ/cb8nvJah+T4aQQxyzl31FbwDFoRr+OBnljw+MU0//5GDTn9IiyZIKp9/teMb9P+rqzBXMAENhA== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Tue, Jun 04, 2024 at 05:49:20PM -0700, Kees Cook wrote: > On Tue, Jun 04, 2024 at 04:13:32PM -0600, Tycho Andersen wrote: > > On Tue, Jun 04, 2024 at 04:02:28PM +0100, Simon Horman wrote: > > > On Fri, May 31, 2024 at 12:14:56PM -0700, Kees Cook wrote: > > > > + for (idx = 0; idx < ARRAY_SIZE(kmalloc_caches[KMALLOC_NORMAL]); idx++) { > > > > + char *short_size, *cache_name; > > > > + unsigned int cache_useroffset, cache_usersize; > > > > + unsigned int size; > > > > + > > > > + if (!kmalloc_caches[KMALLOC_NORMAL][idx]) > > > > + continue; > > > > + > > > > + size = kmalloc_caches[KMALLOC_NORMAL][idx]->object_size; > > > > + if (!size) > > > > + continue; > > > > + > > > > + short_size = strchr(kmalloc_caches[KMALLOC_NORMAL][idx]->name, '-'); > > > > + if (WARN_ON(!short_size)) > > > > + goto fail; > > > > + > > > > + cache_name = kasprintf(GFP_KERNEL, "%s-%s", name, short_size + 1); > > > > + if (WARN_ON(!cache_name)) > > > > + goto fail; > > > > + > > > > + if (useroffset >= size) { > > > > + cache_useroffset = 0; > > > > + cache_usersize = 0; > > > > + } else { > > > > + cache_useroffset = useroffset; > > > > + cache_usersize = min(size - cache_useroffset, usersize); > > > > + } > > > > + (*b)[idx] = kmem_cache_create_usercopy(cache_name, size, > > > > + align, flags, cache_useroffset, > > > > + cache_usersize, ctor); > > > > + kfree(cache_name); > > > > + if (WARN_ON(!(*b)[idx])) > > > > + goto fail; > > > > + } > > > > + > > > > + return b; > > > > + > > > > +fail: > > > > + for (idx = 0; idx < ARRAY_SIZE(kmalloc_caches[KMALLOC_NORMAL]); idx++) { > > > > + if ((*b)[idx]) > > > > + kmem_cache_destroy((*b)[idx]); > > > > > > nit: I don't think it is necessary to guard this with a check for NULL. > > > > Isn't it? What if a kasprintf() fails halfway through the loop? > > He means that kmem_cache_destroy() already checks for NULL. Quite right! > > void kmem_cache_destroy(struct kmem_cache *s) > { > int err = -EBUSY; > bool rcu_set; > > if (unlikely(!s) || !kasan_check_byte(s)) > return; Yes, thanks. That is what I was referring to.