From nobody Sun Feb 8 11:26:42 2026 Received: from out-183.mta1.migadu.com (out-183.mta1.migadu.com [95.215.58.183]) (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 32D5B4502B for ; Thu, 15 Aug 2024 07:21:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.183 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723706511; cv=none; b=gHa3IqJEuNHlvCRlKhfUlZoD1MNpQzKcfclYVTE7/ujIsXEQ9kjmhl+U8hCatbHbtvMZ6A+tHh3FVyQfsQbC5Xn+2N3iNoTybm+KmgtKDev/xbDsmEWqoHysCIEI7ZgEyWJ6vpQnVp4gXgZdh+of9IDBpovBepFQiPhXnaATXq4= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723706511; c=relaxed/simple; bh=3nCv7N/bJGgAFH32cubOSSBl6EN+osyqvORhsEkhCD4=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=OQg78gIBGUOQPmeg5pdz0/GmzDz+TpeBzj9nPtja0yH8o+Ky6SyWEkOEmnNwhWuxfxUhhgPtkY9GEJVBEsJUcz/wP+oFyqsplKFnOMTAXlVU2Wr6MgCZ5akGIb0U2zI/98PkKNZEUfwFgOfmzkpLcX5QHvh4vkXqiHZC2Jw1Xdo= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=BVzWtDEt; arc=none smtp.client-ip=95.215.58.183 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="BVzWtDEt" X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1723706507; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=6L1k8kwIf+HGl+QxmcDKqyyW8jVzFtFYfbXsUufB3qI=; b=BVzWtDEtnr6d3Q7t+dCGnR28ooBnKJ4uUL0e6Q66yUG1p//9oOR3J5bFyWhMXSTtZgp1T+ QNNhaxSCaiWz7RfTZVK+L6TD3+gmZZtoubTF4UgLo8wIC+GIFHjWS/yV6oMW8sV8rcFyHU QKAcp/JWX+8uJM7oKv4hD/JzVlvqTmk= From: Hao Ge To: cl@linux.com, penberg@kernel.org, rientjes@google.com, iamjoonsoo.kim@lge.com, akpm@linux-foundation.org, vbabka@suse.cz, roman.gushchin@linux.dev, 42.hyeyoo@gmail.com, surenb@google.com, kees@kernel.org, kent.overstreet@linux.dev Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Hao Ge Subject: [PATCH] mm/slub: Add check for s->flags in the alloc_tagging_slab_free_hook Date: Thu, 15 Aug 2024 15:21:13 +0800 Message-Id: <20240815072113.30288-1-hao.ge@linux.dev> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Migadu-Flow: FLOW_OUT Content-Type: text/plain; charset="utf-8" From: Hao Ge When enable CONFIG_MEMCG & CONFIG_KFENCE & CONFIG_KMEMLEAK, the following warning always occurs,This is because the following call stack occurred: mem_pool_alloc kmem_cache_alloc_noprof slab_alloc_node kfence_alloc Once the kfence allocation is successful,slab->obj_exts will not be empty. Since in the prepare_slab_obj_exts_hook function,we perform a check for s->flags & (SLAB_NO_OBJ_EXT | SLAB_NOLEAKTRACE),the alloc_tag_add function will not be called as a result.Therefore,ref->ct remains NULL. However,when we call mem_pool_free,since obj_ext is not empty, it eventually leads to the alloc_tag_sub scenario being invoked. This is where the warning occurs. So we should add corresponding checks in the alloc_tagging_slab_free_hook. For __GFP_NO_OBJ_EXT case,I didn't see the specific case where it's using kfence,so I won't add the corresponding check in alloc_tagging_slab_free_hook for now. [ 3.734349] ------------[ cut here ]------------ [ 3.734807] alloc_tag was not set [ 3.735129] WARNING: CPU: 4 PID: 40 at ./include/linux/alloc_tag.h:130 k= mem_cache_free+0x444/0x574 [ 3.735866] Modules linked in: autofs4 [ 3.736211] CPU: 4 UID: 0 PID: 40 Comm: ksoftirqd/4 Tainted: G W = 6.11.0-rc3-dirty #1 [ 3.736969] Tainted: [W]=3DWARN [ 3.737258] Hardware name: QEMU KVM Virtual Machine, BIOS unknown 2/2/20= 22 [ 3.737875] pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE= =3D--) [ 3.738501] pc : kmem_cache_free+0x444/0x574 [ 3.738951] lr : kmem_cache_free+0x444/0x574 [ 3.739361] sp : ffff80008357bb60 [ 3.739693] x29: ffff80008357bb70 x28: 0000000000000000 x27: 00000000000= 00000 [ 3.740338] x26: ffff80008207f000 x25: ffff000b2eb2fd60 x24: ffff0000c00= 05700 [ 3.740982] x23: ffff8000804229e4 x22: ffff800082080000 x21: ffff8000817= 56000 [ 3.741630] x20: fffffd7ff8253360 x19: 00000000000000a8 x18: fffffffffff= fffff [ 3.742274] x17: ffff800ab327f000 x16: ffff800083398000 x15: ffff8000817= 56df0 [ 3.742919] x14: 0000000000000000 x13: 205d344320202020 x12: 5b5d3730383= 43337 [ 3.743560] x11: ffff80008357b650 x10: 000000000000005d x9 : 00000000fff= fffd0 [ 3.744231] x8 : 7f7f7f7f7f7f7f7f x7 : ffff80008237bad0 x6 : c0000000fff= f7fff [ 3.744907] x5 : ffff80008237ba78 x4 : ffff8000820bbad0 x3 : 00000000000= 00001 [ 3.745580] x2 : 68d66547c09f7800 x1 : 68d66547c09f7800 x0 : 00000000000= 00000 [ 3.746255] Call trace: [ 3.746530] kmem_cache_free+0x444/0x574 [ 3.746931] mem_pool_free+0x44/0xf4 [ 3.747306] free_object_rcu+0xc8/0xdc [ 3.747693] rcu_do_batch+0x234/0x8a4 [ 3.748075] rcu_core+0x230/0x3e4 [ 3.748424] rcu_core_si+0x14/0x1c [ 3.748780] handle_softirqs+0x134/0x378 [ 3.749189] run_ksoftirqd+0x70/0x9c [ 3.749560] smpboot_thread_fn+0x148/0x22c [ 3.749978] kthread+0x10c/0x118 [ 3.750323] ret_from_fork+0x10/0x20 [ 3.750696] ---[ end trace 0000000000000000 ]--- Fixes: 4b8736964640 ("mm/slab: add allocation accounting into slab allocati= on and free paths") Signed-off-by: Hao Ge --- mm/slub.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/mm/slub.c b/mm/slub.c index c9d8a2497fd6..1f67621ba6dc 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -2116,6 +2116,9 @@ alloc_tagging_slab_free_hook(struct kmem_cache *s, st= ruct slab *slab, void **p, if (!mem_alloc_profiling_enabled()) return; =20 + if (s->flags & (SLAB_NO_OBJ_EXT | SLAB_NOLEAKTRACE)) + return; + obj_exts =3D slab_obj_exts(slab); if (!obj_exts) return; --=20 2.25.1