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=-5.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY, USER_AGENT_SANE_1 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 705F8C76194 for ; Thu, 25 Jul 2019 21:46:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 49FC122C7B for ; Thu, 25 Jul 2019 21:46:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726764AbfGYVqd (ORCPT ); Thu, 25 Jul 2019 17:46:33 -0400 Received: from out30-57.freemail.mail.aliyun.com ([115.124.30.57]:56406 "EHLO out30-57.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725819AbfGYVqc (ORCPT ); Thu, 25 Jul 2019 17:46:32 -0400 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R111e4;CH=green;DM=||false|;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e01422;MF=yang.shi@linux.alibaba.com;NM=1;PH=DS;RN=5;SR=0;TI=SMTPD_---0TXnk7fc_1564091186; Received: from US-143344MP.local(mailfrom:yang.shi@linux.alibaba.com fp:SMTPD_---0TXnk7fc_1564091186) by smtp.aliyun-inc.com(127.0.0.1); Fri, 26 Jul 2019 05:46:28 +0800 Subject: Re: list corruption in deferred_split_scan() To: Qian Cai Cc: "Kirill A. Shutemov" , akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <1562795006.8510.19.camel@lca.pw> <1564002826.11067.17.camel@lca.pw> From: Yang Shi Message-ID: Date: Thu, 25 Jul 2019 14:46:22 -0700 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.12; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 MIME-Version: 1.0 In-Reply-To: <1564002826.11067.17.camel@lca.pw> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 7/24/19 2:13 PM, Qian Cai wrote: > On Wed, 2019-07-10 at 17:43 -0400, Qian Cai wrote: >> Running LTP oom01 test case with swap triggers a crash below. Revert the >> series >> "Make deferred split shrinker memcg aware" [1] seems fix the issue. > You might want to look harder on this commit, as reverted it alone on the top of > 5.2.0-next-20190711 fixed the issue. > > aefde94195ca mm: thp: make deferred split shrinker memcg aware [1] > > [1] https://lore.kernel.org/linux-mm/1561507361-59349-5-git-send-email-yang.shi@ > linux.alibaba.com/ This is the real meat of the patch series, which converted to memcg deferred split queue actually. > > > list_del corruption. prev->next should be ffffea0022b10098, but was > 0000000000000000 Finally I could reproduce the list corruption issue on my machine with THP swap (swap device is fast device). I should checked this with you at the first place. The problem can't be reproduced with rotate swap device. So, I'm supposed you were using THP swap too. Actually, I found two issues with THP swap: 1. free_transhuge_page() is called in reclaim path instead of put_page. The mem_cgroup_uncharge() is called before free_transhuge_page() in reclaim path, which causes page->mem_cgroup is NULL so the wrong deferred_split_queue would be used, so the THP was not deleted from the memcg's list at all. Then the page might be split or reused later, page->mapping would be override. 2. There is a race condition caused by try_to_unmap() with THP swap. The try_to_unmap() just calls page_remove_rmap() to add THP to deferred split queue in reclaim path. This might cause the below race condition to corrupt the list:                   A                                      B deferred_split_scan     list_move                                                try_to_unmap                                                       list_add_tail list_splice <-- The list might get corrupted here                                                free_transhuge_page                                                       list_del <-- kernel bug triggered I hope the below patch would solve your problem (tested locally). diff --git a/mm/huge_memory.c b/mm/huge_memory.c index b7f709d..d6612ec 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -2830,6 +2830,19 @@ void deferred_split_huge_page(struct page *page)         VM_BUG_ON_PAGE(!PageTransHuge(page), page); +       /* +        * The try_to_unmap() in page reclaim path might reach here too, +        * this may cause a race condition to corrupt deferred split queue. +        * And, if page reclaim is already handling the same page, it is +        * unnecessary to handle it again in shrinker. +        * +        * Check PageSwapCache to determine if the page is being +        * handled by page reclaim since THP swap would add the page into +        * swap cache before reaching try_to_unmap(). +        */ +       if (PageSwapCache(page)) +               return; +         spin_lock_irqsave(&ds_queue->split_queue_lock, flags);         if (list_empty(page_deferred_list(page))) {                 count_vm_event(THP_DEFERRED_SPLIT_PAGE); diff --git a/mm/vmscan.c b/mm/vmscan.c index a0301ed..40c684a 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -1485,10 +1485,9 @@ static unsigned long shrink_page_list(struct list_head *page_list,                  * Is there need to periodically free_page_list? It would                  * appear not as the counts should be low                  */ -               if (unlikely(PageTransHuge(page))) { -                       mem_cgroup_uncharge(page); +               if (unlikely(PageTransHuge(page)))                         (*get_compound_page_dtor(page))(page); -               } else +               else                         list_add(&page->lru, &free_pages);                 continue; @@ -1909,7 +1908,6 @@ static unsigned noinline_for_stack move_pages_to_lru(struct lruvec *lruvec,                         if (unlikely(PageCompound(page))) { spin_unlock_irq(&pgdat->lru_lock); -                               mem_cgroup_uncharge(page); (*get_compound_page_dtor(page))(page); spin_lock_irq(&pgdat->lru_lock);                         } else > [  685.284254][ T3456] ------------[ cut here ]------------ > [  685.289616][ T3456] kernel BUG at lib/list_debug.c:53! > [  685.294808][ T3456] invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN NOPTI > [  685.301998][ T3456] CPU: 5 PID: 3456 Comm: oom01 Tainted: > G        W         5.2.0-next-20190711+ #3 > [  685.311193][ T3456] Hardware name: HPE ProLiant DL385 Gen10/ProLiant DL385 > Gen10, BIOS A40 06/24/2019 > [  685.320485][ T3456] RIP: 0010:__list_del_entry_valid+0x8b/0xb6 > [  685.326364][ T3456] Code: f1 e0 ff 49 8b 55 08 4c 39 e2 75 2c 5b b8 01 00 00 > 00 41 5c 41 5d 5d c3 4c 89 e2 48 89 de 48 c7 c7 c0 5a 73 a3 e8 d9 fa bc ff <0f> > 0b 48 c7 c7 60 a0 e1 a3 e8 13 52 01 00 4c 89 e6 48 c7 c7 20 5b > [  685.345956][ T3456] RSP: 0018:ffff888e0c8a73c0 EFLAGS: 00010082 > [  685.351920][ T3456] RAX: 0000000000000054 RBX: ffffea0022b10098 RCX: > ffffffffa2d5d708 > [  685.359807][ T3456] RDX: 0000000000000000 RSI: 0000000000000008 RDI: > ffff8888442bd380 > [  685.367693][ T3456] RBP: ffff888e0c8a73d8 R08: ffffed1108857a71 R09: > ffffed1108857a70 > [  685.375577][ T3456] R10: ffffed1108857a70 R11: ffff8888442bd387 R12: > 0000000000000000 > [  685.383462][ T3456] R13: 0000000000000000 R14: ffffea0022b10034 R15: > ffffea0022b10098 > [  685.391348][ T3456] FS:  00007fbe26db4700(0000) GS:ffff888844280000(0000) > knlGS:0000000000000000 > [  685.400194][ T3456] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > [  685.406681][ T3456] CR2: 00007fbcabb3f000 CR3: 0000001012e44000 CR4: > 00000000001406a0 > [  685.414563][ T3456] Call Trace: > [  685.417736][ T3456]  deferred_split_scan+0x337/0x740 > [  685.422741][ T3456]  ? split_huge_page_to_list+0xe10/0xe10 > [  685.428272][ T3456]  ? __radix_tree_lookup+0x12d/0x1e0 > [  685.433453][ T3456]  ? node_tag_get.part.0.constprop.6+0x40/0x40 > [  685.439505][ T3456]  do_shrink_slab+0x244/0x5a0 > [  685.444071][ T3456]  shrink_slab+0x253/0x440 > [  685.448375][ T3456]  ? unregister_shrinker+0x110/0x110 > [  685.453551][ T3456]  ? kasan_check_read+0x11/0x20 > [  685.458291][ T3456]  ? mem_cgroup_protected+0x20f/0x260 > [  685.463555][ T3456]  shrink_node+0x31e/0xa30 > [  685.467858][ T3456]  ? shrink_node_memcg+0x1560/0x1560 > [  685.473036][ T3456]  ? ktime_get+0x93/0x110 > [  685.477250][ T3456]  do_try_to_free_pages+0x22f/0x820 > [  685.482338][ T3456]  ? shrink_node+0xa30/0xa30 > [  685.486815][ T3456]  ? kasan_check_read+0x11/0x20 > [  685.491556][ T3456]  ? check_chain_key+0x1df/0x2e0 > [  685.496383][ T3456]  try_to_free_pages+0x242/0x4d0 > [  685.501209][ T3456]  ? do_try_to_free_pages+0x820/0x820 > [  685.506476][ T3456]  __alloc_pages_nodemask+0x9ce/0x1bc0 > [  685.511826][ T3456]  ? gfp_pfmemalloc_allowed+0xc0/0xc0 > [  685.517089][ T3456]  ? kasan_check_read+0x11/0x20 > [  685.521826][ T3456]  ? check_chain_key+0x1df/0x2e0 > [  685.526657][ T3456]  ? do_anonymous_page+0x343/0xe30 > [  685.531658][ T3456]  ? lock_downgrade+0x390/0x390 > [  685.536399][ T3456]  ? get_kernel_page+0xa0/0xa0 > [  685.541050][ T3456]  ? __lru_cache_add+0x108/0x160 > [  685.545879][ T3456]  alloc_pages_vma+0x89/0x2c0 > [  685.550444][ T3456]  do_anonymous_page+0x3e1/0xe30 > [  685.555271][ T3456]  ? __update_load_avg_cfs_rq+0x2c/0x490 > [  685.560796][ T3456]  ? finish_fault+0x120/0x120 > [  685.565361][ T3456]  ? alloc_pages_vma+0x21e/0x2c0 > [  685.570187][ T3456]  handle_pte_fault+0x457/0x12c0 > [  685.575014][ T3456]  __handle_mm_fault+0x79a/0xa50 > [  685.579841][ T3456]  ? vmf_insert_mixed_mkwrite+0x20/0x20 > [  685.585280][ T3456]  ? kasan_check_read+0x11/0x20 > [  685.590021][ T3456]  ? __count_memcg_events+0x8b/0x1c0 > [  685.595196][ T3456]  handle_mm_fault+0x17f/0x370 > [  685.599850][ T3456]  __do_page_fault+0x25b/0x5d0 > [  685.604501][ T3456]  do_page_fault+0x4c/0x2cf > [  685.608892][ T3456]  ? page_fault+0x5/0x20 > [  685.613019][ T3456]  page_fault+0x1b/0x20 > [  685.617058][ T3456] RIP: 0033:0x410be0 > [  685.620840][ T3456] Code: 89 de e8 e3 23 ff ff 48 83 f8 ff 0f 84 86 00 00 00 > 48 89 c5 41 83 fc 02 74 28 41 83 fc 03 74 62 e8 95 29 ff ff 31 d2 48 98 90 > 44 15 00 07 48 01 c2 48 39 d3 7f f3 31 c0 5b 5d 41 5c c3 0f 1f > [  68[  687.120156][ T3456] Shutting down cpus with NMI > [  687.124731][ T3456] Kernel Offset: 0x21800000 from 0xffffffff81000000 > (relocation range: 0xffffffff80000000-0xffffffffbfffffff) > [  687.136389][ T3456] ---[ end Kernel panic - not syncing: Fatal exception ]---