From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Morton Subject: [patch 03/15] mm/page_alloc: fix watchdog soft lockups during set_zone_contiguous() Date: Thu, 07 May 2020 18:35:46 -0700 Message-ID: <20200508013546.5KqzoUC9B%akpm@linux-foundation.org> References: <20200507183509.c5ef146c5aaeb118a25a39a8@linux-foundation.org> Reply-To: linux-kernel@vger.kernel.org Return-path: Received: from mail.kernel.org ([198.145.29.99]:58292 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726514AbgEHBfs (ORCPT ); Thu, 7 May 2020 21:35:48 -0400 In-Reply-To: <20200507183509.c5ef146c5aaeb118a25a39a8@linux-foundation.org> Sender: mm-commits-owner@vger.kernel.org List-Id: mm-commits@vger.kernel.org To: akpm@linux-foundation.org, alexander.duyck@gmail.com, bhe@redhat.com, daniel.m.jordan@oracle.com, david@redhat.com, ktkhai@virtuozzo.com, linux-mm@kvack.org, mhocko@kernel.org, mhocko@suse.com, mm-commits@vger.kernel.org, osalvador@suse.de, pankaj.gupta.linux@gmail.com, pasha.tatashin@soleen.com, shile.zhang@linux.alibaba.com, stable@vger.kernel.org, torvalds@linux-foundation.org From: David Hildenbrand Subject: mm/page_alloc: fix watchdog soft lockups during set_zone_contiguous() Without CONFIG_PREEMPT, it can happen that we get soft lockups detected, e.g., while booting up. [ 105.608900] watchdog: BUG: soft lockup - CPU#0 stuck for 22s! [swapper/0:1] [ 105.608933] Modules linked in: [ 105.608933] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.6.0-next-20200331+ #4 [ 105.608933] Hardware name: Red Hat KVM, BIOS 1.11.1-4.module+el8.1.0+4066+0f1aadab 04/01/2014 [ 105.608933] RIP: 0010:__pageblock_pfn_to_page+0x134/0x1c0 [ 105.608933] Code: 85 c0 74 71 4a 8b 04 d0 48 85 c0 74 68 48 01 c1 74 63 f6 01 04 74 5e 48 c1 e7 06 4c 8b 05 cc 991 [ 105.608933] RSP: 0000:ffffb6d94000fe60 EFLAGS: 00010286 ORIG_RAX: ffffffffffffff13 [ 105.608933] RAX: fffff81953250000 RBX: 000000000a4c9600 RCX: ffff8fe9ff7c1990 [ 105.608933] RDX: ffff8fe9ff7dab80 RSI: 000000000a4c95ff RDI: 0000000293250000 [ 105.608933] RBP: ffff8fe9ff7dab80 R08: fffff816c0000000 R09: 0000000000000008 [ 105.608933] R10: 0000000000000014 R11: 0000000000000014 R12: 0000000000000000 [ 105.608933] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 [ 105.608933] FS: 0000000000000000(0000) GS:ffff8fe1ff400000(0000) knlGS:0000000000000000 [ 105.608933] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 105.608933] CR2: 000000000f613000 CR3: 00000088cf20a000 CR4: 00000000000006f0 [ 105.608933] Call Trace: [ 105.608933] set_zone_contiguous+0x56/0x70 [ 105.608933] page_alloc_init_late+0x166/0x176 [ 105.608933] kernel_init_freeable+0xfa/0x255 [ 105.608933] ? rest_init+0xaa/0xaa [ 105.608933] kernel_init+0xa/0x106 [ 105.608933] ret_from_fork+0x35/0x40 The issue becomes visible when having a lot of memory (e.g., 4TB) assigned to a single NUMA node - a system that can easily be created using QEMU. Inside VMs on a hypervisor with quite some memory overcommit, this is fairly easy to trigger. Link: http://lkml.kernel.org/r/20200416073417.5003-1-david@redhat.com Signed-off-by: David Hildenbrand Reviewed-by: Pavel Tatashin Reviewed-by: Pankaj Gupta Reviewed-by: Baoquan He Reviewed-by: Shile Zhang Acked-by: Michal Hocko Cc: Kirill Tkhai Cc: Shile Zhang Cc: Pavel Tatashin Cc: Daniel Jordan Cc: Michal Hocko Cc: Alexander Duyck Cc: Baoquan He Cc: Oscar Salvador Cc: Signed-off-by: Andrew Morton --- mm/page_alloc.c | 1 + 1 file changed, 1 insertion(+) --- a/mm/page_alloc.c~mm-page_alloc-fix-watchdog-soft-lockups-during-set_zone_contiguous +++ a/mm/page_alloc.c @@ -1607,6 +1607,7 @@ void set_zone_contiguous(struct zone *zo if (!__pageblock_pfn_to_page(block_start_pfn, block_end_pfn, zone)) return; + cond_resched(); } /* We confirm that there is no hole */ _