From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5CC422DC359 for ; Tue, 27 Jan 2026 02:57:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769482672; cv=none; b=d4jjgUKgTWPtF3mpnVxXQAIWdno6NKSdQTqAJ9sM7H4iH1fhX5yJQqyUByzH3eLxEwk2SL7iybx09ogYUqrOU6Fw/yvaLqPlN/GybLa/lBpiBZk1yMmBkXOR6n3oWlrjIkVN8xRffISRtm/17adWvOoY9KyCqOVWchwpKGhoNLk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769482672; c=relaxed/simple; bh=tAqLRk9Ur7XKmepebkA++KUgvbV71gYMLt/1aPQXoa4=; h=Date:To:From:Subject:Message-Id; b=ClEq4xoj9d/RvFYmdNfGyKz636pA5q3P2u8ZENk+cx2c1EPvITsokGAn0oHq8P8uAEUbuiTbBnpSzlHov7Cb1vu22CsmGzFNsSzcpD/BjFg+doNt4MogsepnvLuT8t6IUcXMUYjL1ZtkfoJ8OrhQCXByRD4TIHTgfucOxG4O8dA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=SK4TsK+S; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="SK4TsK+S" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2540EC2BCAF; Tue, 27 Jan 2026 02:57:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1769482672; bh=tAqLRk9Ur7XKmepebkA++KUgvbV71gYMLt/1aPQXoa4=; h=Date:To:From:Subject:From; b=SK4TsK+SSCdilJBrRU7u6var7MjlrTujdddO+64Ge/wQm3jsNVWnfnDu34Uid9GXv AQjBxddCI2TEzej5VYNVwoOT5rTsR58zfRhl6pmUkRlQ+Bv6k/8H8iytOFAmOH38LL hln1uuiZo3U0a036lJhS/C7gSoZvmsKsRS1ZxUuI= Date: Mon, 26 Jan 2026 18:57:51 -0800 To: mm-commits@vger.kernel.org,stable@vger.kernrl.org,rppt@kernel.org,rostedt@goodmis.org,richard.weiyang@gmail.com,paulmck@kernel.org,david@kernel.org,bigeasy@linutronix.de,longman@redhat.com,akpm@linux-foundation.org From: Andrew Morton Subject: [merged mm-hotfixes-stable] mm-mm_init-dont-cond_resched-in-deferred_init_memmap_chunk-if-called-from-deferred_grow_zone.patch removed from -mm tree Message-Id: <20260127025752.2540EC2BCAF@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The quilt patch titled Subject: mm/mm_init: don't cond_resched() in deferred_init_memmap_chunk() if called from deferred_grow_zone() has been removed from the -mm tree. Its filename was mm-mm_init-dont-cond_resched-in-deferred_init_memmap_chunk-if-called-from-deferred_grow_zone.patch This patch was dropped because it was merged into the mm-hotfixes-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Waiman Long Subject: 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 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. Link: https://lkml.kernel.org/r/20260122184343.546627-1-longman@redhat.com Fixes: 3acb913c9d5b ("mm/mm_init: use deferred_init_memmap_chunk() in deferred_grow_zone()") Signed-off-by: Waiman Long Suggested-by: Sebastian Andrzej Siewior Reviewed-by: Sebastian Andrzej Siewior Reviewed-by: Mike Rapoport (Microsoft) Cc: David Hildenbrand Cc: "Paul E . McKenney" Cc: Steven Rostedt Cc: Wei Yang Cc: Signed-off-by: Andrew Morton --- mm/mm_init.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) --- a/mm/mm_init.c~mm-mm_init-dont-cond_resched-in-deferred_init_memmap_chunk-if-called-from-deferred_grow_zone +++ a/mm/mm_init.c @@ -2056,7 +2056,7 @@ static unsigned long __init deferred_ini */ 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; @@ -2082,10 +2082,10 @@ deferred_init_memmap_chunk(unsigned long spfn = chunk_end; - if (irqs_disabled()) - touch_nmi_watchdog(); - else + if (can_resched) cond_resched(); + else + touch_nmi_watchdog(); } } @@ -2098,7 +2098,7 @@ deferred_init_memmap_job(unsigned long s { 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 @@ -2213,7 +2213,7 @@ bool __init deferred_grow_zone(struct zo 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); } /* _ Patches currently in -mm which might be from longman@redhat.com are