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[209.132.180.67]) by mx.google.com with ESMTP id t22si19720699plo.79.2019.03.27.11.46.33; Wed, 27 Mar 2019 11:46:51 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@kernel.org header.s=default header.b=ZJ16+x4X; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2391485AbfC0SpN (ORCPT + 99 others); Wed, 27 Mar 2019 14:45:13 -0400 Received: from mail.kernel.org ([198.145.29.99]:38896 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389953AbfC0SVG (ORCPT ); Wed, 27 Mar 2019 14:21:06 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id CE4FA20651; Wed, 27 Mar 2019 18:21:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1553710866; bh=yydLH4pFYt7J7Oz/YD1nkgWHEuHm4AUgTA3iT764s1A=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ZJ16+x4X9+Xr0KANdy52RAiPPzoHwj8/zu/JgJEzlA+tFQyaODcrIFTM+mXQbsQY3 DUFXZkwS6eBz1GxaNx+T3IVZP8YrTrkW/OhKQLkwTjPJDMNhO67b3yMZYyL1R6RLY8 sGHphdYQCQUJjkxm1S9UHDF24vUBkBab6CIYMrEc= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Qian Cai , Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , Catalin Marinas , Andrew Morton , Linus Torvalds , Sasha Levin , linux-mm@kvack.org Subject: [PATCH AUTOSEL 4.9 13/87] mm/slab.c: kmemleak no scan alien caches Date: Wed, 27 Mar 2019 14:19:26 -0400 Message-Id: <20190327182040.17444-13-sashal@kernel.org> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20190327182040.17444-1-sashal@kernel.org> References: <20190327182040.17444-1-sashal@kernel.org> MIME-Version: 1.0 X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Qian Cai [ Upstream commit 92d1d07daad65c300c7d0b68bbef8867e9895d54 ] Kmemleak throws endless warnings during boot due to in __alloc_alien_cache(), alc = kmalloc_node(memsize, gfp, node); init_arraycache(&alc->ac, entries, batch); kmemleak_no_scan(ac); Kmemleak does not track the array cache (alc->ac) but the alien cache (alc) instead, so let it track the latter by lifting kmemleak_no_scan() out of init_arraycache(). There is another place that calls init_arraycache(), but alloc_kmem_cache_cpus() uses the percpu allocation where will never be considered as a leak. kmemleak: Found object by alias at 0xffff8007b9aa7e38 CPU: 190 PID: 1 Comm: swapper/0 Not tainted 5.0.0-rc2+ #2 Call trace: dump_backtrace+0x0/0x168 show_stack+0x24/0x30 dump_stack+0x88/0xb0 lookup_object+0x84/0xac find_and_get_object+0x84/0xe4 kmemleak_no_scan+0x74/0xf4 setup_kmem_cache_node+0x2b4/0x35c __do_tune_cpucache+0x250/0x2d4 do_tune_cpucache+0x4c/0xe4 enable_cpucache+0xc8/0x110 setup_cpu_cache+0x40/0x1b8 __kmem_cache_create+0x240/0x358 create_cache+0xc0/0x198 kmem_cache_create_usercopy+0x158/0x20c kmem_cache_create+0x50/0x64 fsnotify_init+0x58/0x6c do_one_initcall+0x194/0x388 kernel_init_freeable+0x668/0x688 kernel_init+0x18/0x124 ret_from_fork+0x10/0x18 kmemleak: Object 0xffff8007b9aa7e00 (size 256): kmemleak: comm "swapper/0", pid 1, jiffies 4294697137 kmemleak: min_count = 1 kmemleak: count = 0 kmemleak: flags = 0x1 kmemleak: checksum = 0 kmemleak: backtrace: kmemleak_alloc+0x84/0xb8 kmem_cache_alloc_node_trace+0x31c/0x3a0 __kmalloc_node+0x58/0x78 setup_kmem_cache_node+0x26c/0x35c __do_tune_cpucache+0x250/0x2d4 do_tune_cpucache+0x4c/0xe4 enable_cpucache+0xc8/0x110 setup_cpu_cache+0x40/0x1b8 __kmem_cache_create+0x240/0x358 create_cache+0xc0/0x198 kmem_cache_create_usercopy+0x158/0x20c kmem_cache_create+0x50/0x64 fsnotify_init+0x58/0x6c do_one_initcall+0x194/0x388 kernel_init_freeable+0x668/0x688 kernel_init+0x18/0x124 kmemleak: Not scanning unknown object at 0xffff8007b9aa7e38 CPU: 190 PID: 1 Comm: swapper/0 Not tainted 5.0.0-rc2+ #2 Call trace: dump_backtrace+0x0/0x168 show_stack+0x24/0x30 dump_stack+0x88/0xb0 kmemleak_no_scan+0x90/0xf4 setup_kmem_cache_node+0x2b4/0x35c __do_tune_cpucache+0x250/0x2d4 do_tune_cpucache+0x4c/0xe4 enable_cpucache+0xc8/0x110 setup_cpu_cache+0x40/0x1b8 __kmem_cache_create+0x240/0x358 create_cache+0xc0/0x198 kmem_cache_create_usercopy+0x158/0x20c kmem_cache_create+0x50/0x64 fsnotify_init+0x58/0x6c do_one_initcall+0x194/0x388 kernel_init_freeable+0x668/0x688 kernel_init+0x18/0x124 ret_from_fork+0x10/0x18 Link: http://lkml.kernel.org/r/20190129184518.39808-1-cai@lca.pw Fixes: 1fe00d50a9e8 ("slab: factor out initialization of array cache") Signed-off-by: Qian Cai Reviewed-by: Andrew Morton Cc: Christoph Lameter Cc: Pekka Enberg Cc: David Rientjes Cc: Joonsoo Kim Cc: Catalin Marinas Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin --- mm/slab.c | 17 +++++++++-------- 1 file changed, 9 insertions(+), 8 deletions(-) diff --git a/mm/slab.c b/mm/slab.c index 354a09deecff..d2c0499c6b15 100644 --- a/mm/slab.c +++ b/mm/slab.c @@ -566,14 +566,6 @@ static void start_cpu_timer(int cpu) static void init_arraycache(struct array_cache *ac, int limit, int batch) { - /* - * The array_cache structures contain pointers to free object. - * However, when such objects are allocated or transferred to another - * cache the pointers are not cleared and they could be counted as - * valid references during a kmemleak scan. Therefore, kmemleak must - * not scan such objects. - */ - kmemleak_no_scan(ac); if (ac) { ac->avail = 0; ac->limit = limit; @@ -589,6 +581,14 @@ static struct array_cache *alloc_arraycache(int node, int entries, struct array_cache *ac = NULL; ac = kmalloc_node(memsize, gfp, node); + /* + * The array_cache structures contain pointers to free object. + * However, when such objects are allocated or transferred to another + * cache the pointers are not cleared and they could be counted as + * valid references during a kmemleak scan. Therefore, kmemleak must + * not scan such objects. + */ + kmemleak_no_scan(ac); init_arraycache(ac, entries, batchcount); return ac; } @@ -683,6 +683,7 @@ static struct alien_cache *__alloc_alien_cache(int node, int entries, alc = kmalloc_node(memsize, gfp, node); if (alc) { + kmemleak_no_scan(alc); init_arraycache(&alc->ac, entries, batch); spin_lock_init(&alc->lock); } -- 2.19.1