From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C8239C433DF for ; Tue, 2 Jun 2020 04:45:56 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 85F13206C3 for ; Tue, 2 Jun 2020 04:45:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="eF1pMg0G" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 85F13206C3 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 2A4858000D; Tue, 2 Jun 2020 00:45:56 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 27C1780010; Tue, 2 Jun 2020 00:45:56 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 1C2838000D; Tue, 2 Jun 2020 00:45:56 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0102.hostedemail.com [216.40.44.102]) by kanga.kvack.org (Postfix) with ESMTP id 017B38000D for ; Tue, 2 Jun 2020 00:45:55 -0400 (EDT) Received: from smtpin02.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id B302E4417 for ; Tue, 2 Jun 2020 04:45:55 +0000 (UTC) X-FDA: 76883034270.02.cry36_169a3818efb50 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin02.hostedemail.com (Postfix) with ESMTP id 7F47C3ABF for ; Tue, 2 Jun 2020 04:45:55 +0000 (UTC) X-HE-Tag: cry36_169a3818efb50 X-Filterd-Recvd-Size: 4004 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf08.hostedemail.com (Postfix) with ESMTP for ; Tue, 2 Jun 2020 04:45:55 +0000 (UTC) Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 213832074B; Tue, 2 Jun 2020 04:45:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591073154; bh=PUXw7RZdHTBOXFecDynk6HOPkSGenCTvJKGvW7E52Qo=; h=Date:From:To:Subject:In-Reply-To:From; b=eF1pMg0GIGBjP6NDKOHKXaDZMc34f8enm8lyfz5msfy4V8qs62L8yKpuDfaxxWYPy IMAhceWhRAPrriM908uQi+49rQhgaEPAHOUwVl1SNrW1Fa7V34oFG//9ulahdx7wxU 2OWehleLSQrVdlTLHwjuVS0VEC0v0ebFciNn63+I= Date: Mon, 01 Jun 2020 21:45:53 -0700 From: Andrew Morton To: akpm@linux-foundation.org, cl@linux.com, iamjoonsoo.kim@lge.com, kirill.shutemov@linux.intel.com, linux-mm@kvack.org, mm-commits@vger.kernel.org, penberg@kernel.org, penguin-kernel@i-love.sakura.ne.jp, rientjes@google.com, torvalds@linux-foundation.org, yuzhao@google.com Subject: [patch 010/128] slub: remove kmalloc under list_lock from list_slab_objects() V2 Message-ID: <20200602044553.97d8wh_k1%akpm@linux-foundation.org> In-Reply-To: <20200601214457.919c35648e96a2b46b573fe1@linux-foundation.org> User-Agent: s-nail v14.8.16 X-Rspamd-Queue-Id: 7F47C3ABF X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam04 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: From: Christopher Lameter Subject: slub: remove kmalloc under list_lock from list_slab_objects() V2 list_slab_objects() is called when a slab is destroyed and there are objects still left to list the objects in the syslog. This is a pretty rare event. And there it seems we take the list_lock and call kmalloc while holding that lock. Perform the allocation in free_partial() before the list_lock is taken. Link: http://lkml.kernel.org/r/alpine.DEB.2.21.2002031721250.1668@www.lameter.com Fixes: bbd7d57bfe852d9788bae5fb171c7edb4021d8ac ("slub: Potential stack overflow") Signed-off-by: Christopher Lameter Cc: Pekka Enberg Cc: David Rientjes Cc: Joonsoo Kim Cc: "Kirill A. Shutemov" Cc: Tetsuo Handa Cc: Yu Zhao Signed-off-by: Andrew Morton --- mm/slub.c | 20 +++++++++++++++----- 1 file changed, 15 insertions(+), 5 deletions(-) --- a/mm/slub.c~slub-remove-kmalloc-under-list_lock-from-list_slab_objects +++ a/mm/slub.c @@ -3766,12 +3766,14 @@ error: } static void list_slab_objects(struct kmem_cache *s, struct page *page, - const char *text) + const char *text, unsigned long *map) { #ifdef CONFIG_SLUB_DEBUG void *addr = page_address(page); void *p; - unsigned long *map; + + if (!map) + return; slab_err(s, page, text, s->name); slab_lock(page); @@ -3784,8 +3786,6 @@ static void list_slab_objects(struct kme print_tracking(s, p); } } - put_map(map); - slab_unlock(page); #endif } @@ -3799,6 +3799,11 @@ static void free_partial(struct kmem_cac { LIST_HEAD(discard); struct page *page, *h; + unsigned long *map = NULL; + +#ifdef CONFIG_SLUB_DEBUG + map = bitmap_alloc(oo_objects(s->max), GFP_KERNEL); +#endif BUG_ON(irqs_disabled()); spin_lock_irq(&n->list_lock); @@ -3808,11 +3813,16 @@ static void free_partial(struct kmem_cac list_add(&page->slab_list, &discard); } else { list_slab_objects(s, page, - "Objects remaining in %s on __kmem_cache_shutdown()"); + "Objects remaining in %s on __kmem_cache_shutdown()", + map); } } spin_unlock_irq(&n->list_lock); +#ifdef CONFIG_SLUB_DEBUG + bitmap_free(map); +#endif + list_for_each_entry_safe(page, h, &discard, slab_list) discard_slab(s, page); } _