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Fri, 06 Feb 2026 05:41:35 -0800 (PST) Received: from localhost ([196.207.164.177]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-4362972fc1bsm6103719f8f.28.2026.02.06.05.41.35 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 06 Feb 2026 05:41:35 -0800 (PST) Date: Fri, 6 Feb 2026 16:41:32 +0300 From: Dan Carpenter To: Jens Axboe Cc: linux-block@vger.kernel.org, linux-kernel Subject: [bug report] bio: add allocation cache abstraction Message-ID: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: [ Smatch checking is paused while we raise funding. #SadFace https://lore.kernel.org/all/aTaiGSbWZ9DJaGo7@stanley.mountain/ -dan ] Hello Jens Axboe, Commit be4d234d7aeb ("bio: add allocation cache abstraction") from Mar 8, 2021 (linux-next), leads to the following Smatch static checker warning: block/bio.c:790 bio_cpu_dead() error: potential null dereference 'bs'. (hlist_entry_safe() returns null) block/bio.c 785 static int bio_cpu_dead(unsigned int cpu, struct hlist_node *node) 786 { 787 struct bio_set *bs; 788 789 bs = hlist_entry_safe(node, struct bio_set, cpuhp_dead); --> 790 if (bs->cache) { It doesn't really make sense to use hlist_entry_safe() instead of hlist_entry() if we're not going to check for NULL. 791 struct bio_alloc_cache *cache = per_cpu_ptr(bs->cache, cpu); 792 793 bio_alloc_cache_prune(cache, -1U); 794 } 795 return 0; 796 } regards, dan carpenter