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=-16.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=unavailable 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 D3FF6C07E96 for ; Thu, 8 Jul 2021 13:12:07 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 6DF8A61466 for ; Thu, 8 Jul 2021 13:12:07 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6DF8A61466 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 5A8296B006C; Thu, 8 Jul 2021 09:12:07 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 57E266B0070; Thu, 8 Jul 2021 09:12:07 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 4481A6B0071; Thu, 8 Jul 2021 09:12:07 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0206.hostedemail.com [216.40.44.206]) by kanga.kvack.org (Postfix) with ESMTP id 1B9326B006C for ; Thu, 8 Jul 2021 09:12:07 -0400 (EDT) Received: from smtpin20.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 6A4DD82ED2EC for ; Thu, 8 Jul 2021 13:12:06 +0000 (UTC) X-FDA: 78339458652.20.08D4E5B Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [216.205.24.124]) by imf29.hostedemail.com (Postfix) with ESMTP id 32641900024E for ; Thu, 8 Jul 2021 13:12:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1625749921; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=Su19WDhoU/YXgcv3TtubE0a9+gNAyxVy+Jnc8J4aC5U=; b=OXRNcMQu697kPpcrLtmNQ+fVZziEHGAZFvu/UMNP6++LuDxEeXiVBEIpHINaSHyUgV5KSw LVHh0LvwjsKBTvdDmIC3tVeKcHER1zkBTAreZ3UJBlC2BJOGXeRoeFQpAZ+/cUKytEnRdb r3smpjS9AWKTZlCQKRQqoey2co3GSII= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-584-GX00-M0UPyaJOTd3kjjI3A-1; Thu, 08 Jul 2021 09:10:26 -0400 X-MC-Unique: GX00-M0UPyaJOTd3kjjI3A-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 690E5192CC6B; Thu, 8 Jul 2021 13:10:24 +0000 (UTC) Received: from optiplex-fbsd (unknown [10.3.128.11]) by smtp.corp.redhat.com (Postfix) with ESMTPS id D9231E2F7; Thu, 8 Jul 2021 13:10:21 +0000 (UTC) Date: Thu, 8 Jul 2021 09:10:18 -0400 From: Rafael Aquini To: Mel Gorman Cc: Andrew Morton , linux-mm@kvack.org, Desmond Cheong Zhi Xi , linux-kernel@vger.kernel.org, skhan@linuxfoundation.org, Zqiang , linux-kernel-mentees@lists.linuxfoundation.org, syzbot+127fd7828d6eeb611703@syzkaller.appspotmail.com Subject: Re: [PATCH] mm/page_alloc: Avoid page allocator recursion with pagesets.lock held Message-ID: References: <20210708081434.GV3840@techsingularity.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210708081434.GV3840@techsingularity.net> X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Authentication-Results: imf29.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=OXRNcMQu; spf=none (imf29.hostedemail.com: domain of aquini@redhat.com has no SPF policy when checking 216.205.24.124) smtp.mailfrom=aquini@redhat.com; dmarc=pass (policy=none) header.from=redhat.com X-Rspamd-Server: rspam05 X-Stat-Signature: 1q6bhun9muehmugphab6wuudpbr5ewxi X-Rspamd-Queue-Id: 32641900024E X-Rspam-User: nil X-HE-Tag: 1625749922-258002 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: On Thu, Jul 08, 2021 at 09:14:34AM +0100, Mel Gorman wrote: > 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:5179 > 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 patches 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 of PAGE_OWNER is ^^^^ Minor nit: s/of/if > active. The caller will be forced to allocate one page at a time incurring > a performance penalty but PAGE_OWNER is already a performance penalty. > > Fixes: dbbee9d5cd83 ("mm/page_alloc: convert per-cpu list protection to local_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 > --- > 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 preferred_nid, > if (nr_pages - nr_populated == 1) > goto failed; > > +#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 &= gfp_allowed_mask; > alloc_gfp = gfp; > Acked-by: Rafael Aquini