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=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham 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 8FDDEC07E95 for ; Tue, 13 Jul 2021 15:21:11 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 4318261376 for ; Tue, 13 Jul 2021 15:21:11 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4318261376 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=techsingularity.net Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 3985F6B0096; Tue, 13 Jul 2021 11:21:05 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 0CFBB6B0098; Tue, 13 Jul 2021 11:21:05 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E3E2F6B009D; Tue, 13 Jul 2021 11:21:04 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0092.hostedemail.com [216.40.44.92]) by kanga.kvack.org (Postfix) with ESMTP id A911E6B0096 for ; Tue, 13 Jul 2021 11:21:04 -0400 (EDT) Received: from smtpin12.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 9ABB91854ADE3 for ; Tue, 13 Jul 2021 15:21:03 +0000 (UTC) X-FDA: 78357927606.12.67AEF36 Received: from outbound-smtp53.blacknight.com (outbound-smtp53.blacknight.com [46.22.136.237]) by imf05.hostedemail.com (Postfix) with ESMTP id BA56A5009F30 for ; Tue, 13 Jul 2021 15:21:02 +0000 (UTC) Received: from mail.blacknight.com (pemlinmail01.blacknight.ie [81.17.254.10]) by outbound-smtp53.blacknight.com (Postfix) with ESMTPS id 24130FAE6E for ; Tue, 13 Jul 2021 16:21:01 +0100 (IST) Received: (qmail 14845 invoked from network); 13 Jul 2021 15:21:00 -0000 Received: from unknown (HELO stampy.112glenside.lan) (mgorman@techsingularity.net@[84.203.17.255]) by 81.17.254.9 with ESMTPA; 13 Jul 2021 15:21:00 -0000 From: Mel Gorman To: Andrew Morton Cc: Desmond Cheong Zhi Xi , Zhang Qiang , Yanfei Xu , Chuck Lever , Jesper Dangaard Brouer , Matteo Croce , Linux-MM , LKML , Mel Gorman Subject: [PATCH 1/4] mm/page_alloc: Avoid page allocator recursion with pagesets.lock held Date: Tue, 13 Jul 2021 16:20:57 +0100 Message-Id: <20210713152100.10381-2-mgorman@techsingularity.net> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20210713152100.10381-1-mgorman@techsingularity.net> References: <20210713152100.10381-1-mgorman@techsingularity.net> MIME-Version: 1.0 X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: BA56A5009F30 X-Stat-Signature: 4qdy3yu4qakmtpfz37qa4oxsj9t9wzgx Authentication-Results: imf05.hostedemail.com; dkim=none; dmarc=none; spf=pass (imf05.hostedemail.com: domain of mgorman@techsingularity.net designates 46.22.136.237 as permitted sender) smtp.mailfrom=mgorman@techsingularity.net X-HE-Tag: 1626189662-915265 Content-Transfer-Encoding: quoted-printable 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: Syzbot is reporting potential deadlocks due to pagesets.lock when PAGE_OWNER is enabled. One example from Desmond Cheong Zhi Xi is as follows __alloc_pages_bulk() local_lock_irqsave(&pagesets.lock, flags) <---- outer lock here prep_new_page(): post_alloc_hook(): set_page_owner(): __set_page_owner(): save_stack(): stack_depot_save(): alloc_pages(): alloc_page_interleave(): __alloc_pages(): get_page_from_freelist(): rm_queue(): rm_queue_pcplist(): local_lock_irqsave(&pagesets.lock, flags); *** DEADLOCK *** Zhang, Qiang also reported BUG: sleeping function called from invalid context at mm/page_alloc.c:5= 179 in_atomic(): 0, irqs_disabled(): 1, non_block: 0, pid: 1, name: swapper= /0 ..... __dump_stack lib/dump_stack.c:79 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:96 ___might_sleep.cold+0x1f1/0x237 kernel/sched/core.c:9153 prepare_alloc_pages+0x3da/0x580 mm/page_alloc.c:5179 __alloc_pages+0x12f/0x500 mm/page_alloc.c:5375 alloc_page_interleave+0x1e/0x200 mm/mempolicy.c:2147 alloc_pages+0x238/0x2a0 mm/mempolicy.c:2270 stack_depot_save+0x39d/0x4e0 lib/stackdepot.c:303 save_stack+0x15e/0x1e0 mm/page_owner.c:120 __set_page_owner+0x50/0x290 mm/page_owner.c:181 prep_new_page mm/page_alloc.c:2445 [inline] __alloc_pages_bulk+0x8b9/0x1870 mm/page_alloc.c:5313 alloc_pages_bulk_array_node include/linux/gfp.h:557 [inline] vm_area_alloc_pages mm/vmalloc.c:2775 [inline] __vmalloc_area_node mm/vmalloc.c:2845 [inline] __vmalloc_node_range+0x39d/0x960 mm/vmalloc.c:2947 __vmalloc_node mm/vmalloc.c:2996 [inline] vzalloc+0x67/0x80 mm/vmalloc.c:3066 There are a number of ways it could be fixed. The page owner code could be audited to strip GFP flags that allow sleeping but it'll impair the functionality of PAGE_OWNER if allocations fail. The bulk allocator could add a special case to release/reacquire the lock for prep_new_page and lookup PCP after the lock is reacquired at the cost of performance. The pages requiring prep could be tracked using the least significant bit and looping through the array although it is more complicated for the list interface. The options are relatively complex and the second one still incurs a performance penalty when PAGE_OWNER is active so this patch takes the simple approach -- disable bulk allocation if PAGE_OWNER = is active. The caller will be forced to allocate one page at a time incurrin= g a performance penalty but PAGE_OWNER is already a performance penalty. Fixes: dbbee9d5cd83 ("mm/page_alloc: convert per-cpu list protection to l= ocal_lock") Reported-by: Desmond Cheong Zhi Xi Reported-by: "Zhang, Qiang" Reported-and-tested-by: syzbot+127fd7828d6eeb611703@syzkaller.appspotmail= .com Signed-off-by: Mel Gorman Acked-by: Rafael Aquini --- mm/page_alloc.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 3b97e17806be..6ef86f338151 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -5239,6 +5239,18 @@ unsigned long __alloc_pages_bulk(gfp_t gfp, int pr= eferred_nid, if (nr_pages - nr_populated =3D=3D 1) goto failed; =20 +#ifdef CONFIG_PAGE_OWNER + /* + * PAGE_OWNER may recurse into the allocator to allocate space to + * save the stack with pagesets.lock held. Releasing/reacquiring + * removes much of the performance benefit of bulk allocation so + * force the caller to allocate one page at a time as it'll have + * similar performance to added complexity to the bulk allocator. + */ + if (static_branch_unlikely(&page_owner_inited)) + goto failed; +#endif + /* May set ALLOC_NOFRAGMENT, fragmentation will return 1 page. */ gfp &=3D gfp_allowed_mask; alloc_gfp =3D gfp; --=20 2.26.2