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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id DDACBD6CFA1 for ; Thu, 22 Jan 2026 18:44:36 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 05F1E6B030C; Thu, 22 Jan 2026 13:44:36 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 0297D6B030E; Thu, 22 Jan 2026 13:44:35 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E43B96B030F; Thu, 22 Jan 2026 13:44:35 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) by kanga.kvack.org (Postfix) with ESMTP id D13316B030C for ; Thu, 22 Jan 2026 13:44:35 -0500 (EST) Received: from smtpin05.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id 7EFBF160502 for ; Thu, 22 Jan 2026 18:44:35 +0000 (UTC) X-FDA: 84360475710.05.B03304B Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by imf20.hostedemail.com (Postfix) with ESMTP id 599351C0006 for ; Thu, 22 Jan 2026 18:44:32 +0000 (UTC) Authentication-Results: imf20.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=ALi65AXK; dmarc=pass (policy=quarantine) header.from=redhat.com; spf=pass (imf20.hostedemail.com: domain of longman@redhat.com designates 170.10.133.124 as permitted sender) smtp.mailfrom=longman@redhat.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1769107472; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-transfer-encoding:content-transfer-encoding: in-reply-to:references:dkim-signature; bh=2hi9nw0ROEqCJmA86cR5BCja4mz2cFCx+tgdx6SAHhI=; b=mHt/KOn+IZWIV/Iw/nTQjX1qBocLSpvphFVNH+ZfLlDTqTmgatWcQin8eENmWpRnd87Lew To75FJx9ZQnJabVEx1mqKpr96w53/ItimVoII4tRHn8yT3byRkuKV+1Lp39p+HH5EXu3c8 NTAZIiSuT8h00fBqAx/DopmE0NHoN90= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1769107472; a=rsa-sha256; cv=none; b=EH23p+C/4lUojkyEX4vkbQ/5RyIAdcB7bzMtPfPGkskl38ia5v8eNrEaezeMecbuUa/Hd6 +YiDHYj8loxhLCGsDyUsrafFj2jna2sub22qEzCctPHYQmf1cI0YXFthzkQpzhXv9pzEZl +Ava4uYmgOJOiXc5L8MCsSMsK6OyzoE= ARC-Authentication-Results: i=1; imf20.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=ALi65AXK; dmarc=pass (policy=quarantine) header.from=redhat.com; spf=pass (imf20.hostedemail.com: domain of longman@redhat.com designates 170.10.133.124 as permitted sender) smtp.mailfrom=longman@redhat.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1769107471; 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=2hi9nw0ROEqCJmA86cR5BCja4mz2cFCx+tgdx6SAHhI=; b=ALi65AXKAa/RU/QRwLIz4ouGQow4ds56RnzyF6ksKi2a+XOJIaoJvjrGklSMmXmvKIETtS /KKWTs4njySuRYyaOBEKBBSgR31ounSd2LbzMPnaBOce/8EgCKNIjoei43RSqJAjO85eBa in7+zZHa4L+m4aDV3VpaTZLueOfCtD0= Received: from mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-450-DrPRUB-MMeeByGpbTwLtaw-1; Thu, 22 Jan 2026 13:44:27 -0500 X-MC-Unique: DrPRUB-MMeeByGpbTwLtaw-1 X-Mimecast-MFC-AGG-ID: DrPRUB-MMeeByGpbTwLtaw_1769107465 Received: from mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.93]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 6209F1955D9F; Thu, 22 Jan 2026 18:44:25 +0000 (UTC) Received: from llong-thinkpadp16vgen1.westford.csb (unknown [10.22.90.13]) by mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id EBA041800665; Thu, 22 Jan 2026 18:44:22 +0000 (UTC) From: Waiman Long To: Mike Rapoport , Andrew Morton , Sebastian Andrzej Siewior , Clark Williams , Steven Rostedt Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-rt-devel@lists.linux.dev, Wei Yang , David Hildenbrand , "Paul E . McKenney" , Waiman Long Subject: [PATCH v3] mm/mm_init: Don't cond_resched() in deferred_init_memmap_chunk() if called from deferred_grow_zone() Date: Thu, 22 Jan 2026 13:43:43 -0500 Message-ID: <20260122184343.546627-1-longman@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.93 X-Rspamd-Queue-Id: 599351C0006 X-Stat-Signature: bho9i5rbu1rt3nexn45yqtgxpcmowo6p X-Rspam-User: X-Rspamd-Server: rspam02 X-HE-Tag: 1769107472-94166 X-HE-Meta: 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 p0idIKIQ M0LQQ2UQ4QtYpDYvNCcr7NX1VBg1kSmhKdVST630DzPt0M9XnOs6NrCtPD7UF07xROhPyc31Ij/X1DY+8SfSgBiZ8XxCLovZbVz9ZwHxgaPGeR62TWZZc1YgwMvRno6kw15ZQ4jz+oe1ZA5TbBn34oK+lR6ZEkaOH+wga+m3raPq40kdwNkQMy4BCxwv8Bjb4LzCnBltN18Gi9TQXcqyq/7veug4ZMmybeHLSOWLYDIRlh3S+lzBkkCkCwdhV0WstXio4KsWDT7LRTLjTb4EYi8ML9Jr5ocwDMeeS1EyY0fiFB2V3x5PMb+SUUMseeJgDc2cBDwd/brskuQqGRGuxTsciqrL5SOmQHu7kmio1DZSa/BnABtML9o3gHxwMjq6e5r4joAIPoLYwT2n8p4zWYnYYEPcYxxFo1fOdr32M4ijABsjYkvUNLoxLetuba0qIW2UcytC6ap5CGnM= 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: List-Subscribe: List-Unsubscribe: Commit 3acb913c9d5b ("mm/mm_init: use deferred_init_memmap_chunk() in deferred_grow_zone()") made deferred_grow_zone() call deferred_init_memmap_chunk() within a pgdat_resize_lock() critical section with irqs disabled. It did check for irqs_disabled() in deferred_init_memmap_chunk() to avoid calling cond_resched(). For a PREEMPT_RT kernel build, however, spin_lock_irqsave() does not disable interrupt but rcu_read_lock() is called. This leads to the following bug report. BUG: sleeping function called from invalid context at mm/mm_init.c:2091 in_atomic(): 0, irqs_disabled(): 0, non_block: 0, pid: 1, name: swapper/0 preempt_count: 0, expected: 0 RCU nest depth: 1, expected: 0 3 locks held by swapper/0/1: #0: ffff80008471b7a0 (sched_domains_mutex){+.+.}-{4:4}, at: sched_domains_mutex_lock+0x28/0x40 #1: ffff003bdfffef48 (&pgdat->node_size_lock){+.+.}-{3:3}, at: deferred_grow_zone+0x140/0x278 #2: ffff800084acf600 (rcu_read_lock){....}-{1:3}, at: rt_spin_lock+0x1b4/0x408 CPU: 0 UID: 0 PID: 1 Comm: swapper/0 Tainted: G W 6.19.0-rc6-test #1 PREEMPT_{RT,(full) } Tainted: [W]=WARN Call trace: show_stack+0x20/0x38 (C) dump_stack_lvl+0xdc/0xf8 dump_stack+0x1c/0x28 __might_resched+0x384/0x530 deferred_init_memmap_chunk+0x560/0x688 deferred_grow_zone+0x190/0x278 _deferred_grow_zone+0x18/0x30 get_page_from_freelist+0x780/0xf78 __alloc_frozen_pages_noprof+0x1dc/0x348 alloc_slab_page+0x30/0x110 allocate_slab+0x98/0x2a0 new_slab+0x4c/0x80 ___slab_alloc+0x5a4/0x770 __slab_alloc.constprop.0+0x88/0x1e0 __kmalloc_node_noprof+0x2c0/0x598 __sdt_alloc+0x3b8/0x728 build_sched_domains+0xe0/0x1260 sched_init_domains+0x14c/0x1c8 sched_init_smp+0x9c/0x1d0 kernel_init_freeable+0x218/0x358 kernel_init+0x28/0x208 ret_from_fork+0x10/0x20 Fix it adding a new argument to deferred_init_memmap_chunk() to explicitly tell it if cond_resched() is allowed or not instead of relying on some current state information which may vary depending on the exact kernel configuration options that are enabled. Fixes: 3acb913c9d5b ("mm/mm_init: use deferred_init_memmap_chunk() in deferred_grow_zone()") Suggested-by: Sebastian Andrzej Siewior Signed-off-by: Waiman Long --- [v3]: Add a new can_resched argument to deferred_init_memmap_chunk() as suggested by Sebastian. mm/mm_init.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/mm/mm_init.c b/mm/mm_init.c index fc2a6f1e518f..2a809cd8e7fa 100644 --- a/mm/mm_init.c +++ b/mm/mm_init.c @@ -2059,7 +2059,7 @@ static unsigned long __init deferred_init_pages(struct zone *zone, */ static unsigned long __init deferred_init_memmap_chunk(unsigned long start_pfn, unsigned long end_pfn, - struct zone *zone) + struct zone *zone, bool can_resched) { int nid = zone_to_nid(zone); unsigned long nr_pages = 0; @@ -2085,10 +2085,10 @@ deferred_init_memmap_chunk(unsigned long start_pfn, unsigned long end_pfn, spfn = chunk_end; - if (irqs_disabled()) - touch_nmi_watchdog(); - else + if (can_resched) cond_resched(); + else + touch_nmi_watchdog(); } } @@ -2101,7 +2101,7 @@ deferred_init_memmap_job(unsigned long start_pfn, unsigned long end_pfn, { struct zone *zone = arg; - deferred_init_memmap_chunk(start_pfn, end_pfn, zone); + deferred_init_memmap_chunk(start_pfn, end_pfn, zone, true); } static unsigned int __init @@ -2216,7 +2216,7 @@ bool __init deferred_grow_zone(struct zone *zone, unsigned int order) for (spfn = first_deferred_pfn, epfn = SECTION_ALIGN_UP(spfn + 1); nr_pages < nr_pages_needed && spfn < zone_end_pfn(zone); spfn = epfn, epfn += PAGES_PER_SECTION) { - nr_pages += deferred_init_memmap_chunk(spfn, epfn, zone); + nr_pages += deferred_init_memmap_chunk(spfn, epfn, zone, false); } /* -- 2.52.0