From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BF89633506F; Fri, 17 Oct 2025 15:23:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760714600; cv=none; b=gxt7qYw9R1UL/qwwecnItse9a4Mz15qd2uUaoSz4NXf5y5SnvZV2hFS9AQ25jerjQYjHKydeDtAbljv6+mm8X3fl8p4fFfKH5lLTaDORRyp/SmLLD3uGS++XlCJfd0t+u+tRlzCop1wpDrm9s0rEEhiuayAtCtBTZpQT74RZZ3Y= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760714600; c=relaxed/simple; bh=DeLTXT9bCgUVw2AIYNmMe3bKezOQI4GW+OsfhvfGJDg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=QWUsncIJvuiTu5RS7KJzejH3cLejNNJYX3A5k5rwhb69uU2bLpu4jNOt1O9yVMUH065QX+N3PiuMcxpUqf+9ovTM3ocQJZ7ROh56waMNJ4NsAo05jigjohTlBJwaI6A/BPyh5E1cblEMV/JFAW3ugLLTiAmdXO7uevMi4/DD+V0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=TKgdrtWr; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="TKgdrtWr" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E5132C4CEFE; Fri, 17 Oct 2025 15:23:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1760714600; bh=DeLTXT9bCgUVw2AIYNmMe3bKezOQI4GW+OsfhvfGJDg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=TKgdrtWrywAGU73I3F3upZUSOz86CBxW7N3jFh2lIYuscuhixI8i4FkcmhPPnze4f 1Dji3XOlQmHXtW4rGYDyRcsxkG6GfKJDbquFPxkwsgCU5lqgvqK3ZBXjGepSWyKEN6 AQKuPsTFsS46We17PPLxDrG9tOYP5+Fb2V3jvgaM= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Shakeel Butt , Suren Baghdasaryan , Vlastimil Babka Subject: [PATCH 6.12 200/277] slab: prevent warnings when slab obj_exts vector allocation fails Date: Fri, 17 Oct 2025 16:53:27 +0200 Message-ID: <20251017145154.423127012@linuxfoundation.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20251017145147.138822285@linuxfoundation.org> References: <20251017145147.138822285@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Suren Baghdasaryan commit 4038016397da5c1cebb10e7c85a36d06123724a8 upstream. When object extension vector allocation fails, we set slab->obj_exts to OBJEXTS_ALLOC_FAIL to indicate the failure. Later, once the vector is successfully allocated, we will use this flag to mark codetag references stored in that vector as empty to avoid codetag warnings. slab_obj_exts() used to retrieve the slab->obj_exts vector pointer checks slab->obj_exts for being either NULL or a pointer with MEMCG_DATA_OBJEXTS bit set. However it does not handle the case when slab->obj_exts equals OBJEXTS_ALLOC_FAIL. Add the missing condition to avoid extra warning. Fixes: 09c46563ff6d ("codetag: debug: introduce OBJEXTS_ALLOC_FAIL to mark failed slab_ext allocations") Reported-by: Shakeel Butt Closes: https://lore.kernel.org/all/jftidhymri2af5u3xtcqry3cfu6aqzte3uzlznhlaylgrdztsi@5vpjnzpsemf5/ Signed-off-by: Suren Baghdasaryan Cc: stable@vger.kernel.org # v6.10+ Acked-by: Shakeel Butt Signed-off-by: Vlastimil Babka Signed-off-by: Greg Kroah-Hartman --- mm/slab.h | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) --- a/mm/slab.h +++ b/mm/slab.h @@ -572,8 +572,12 @@ static inline struct slabobj_ext *slab_o unsigned long obj_exts = READ_ONCE(slab->obj_exts); #ifdef CONFIG_MEMCG - VM_BUG_ON_PAGE(obj_exts && !(obj_exts & MEMCG_DATA_OBJEXTS), - slab_page(slab)); + /* + * obj_exts should be either NULL, a valid pointer with + * MEMCG_DATA_OBJEXTS bit set or be equal to OBJEXTS_ALLOC_FAIL. + */ + VM_BUG_ON_PAGE(obj_exts && !(obj_exts & MEMCG_DATA_OBJEXTS) && + obj_exts != OBJEXTS_ALLOC_FAIL, slab_page(slab)); VM_BUG_ON_PAGE(obj_exts & MEMCG_DATA_KMEM, slab_page(slab)); #endif return (struct slabobj_ext *)(obj_exts & ~OBJEXTS_FLAGS_MASK);