From patchwork Fri Feb 5 02:32:45 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrew Morton X-Patchwork-Id: 378094 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=-15.7 required=3.0 tests=BAYES_00,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 A1338C433DB for ; Fri, 5 Feb 2021 02:34:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5859D64FA7 for ; Fri, 5 Feb 2021 02:34:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230224AbhBECd7 (ORCPT ); Thu, 4 Feb 2021 21:33:59 -0500 Received: from mail.kernel.org ([198.145.29.99]:46194 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230282AbhBECdr (ORCPT ); Thu, 4 Feb 2021 21:33:47 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 57EAC64FC2; Fri, 5 Feb 2021 02:32:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1612492367; bh=QB1ZdaxTR3P9QGE1uq+nTRbZqdQOxGc8pgnARUwOAgQ=; h=Date:From:To:Subject:In-Reply-To:From; b=m1jca+IunX4b4dv/QpJrwFzHZhGgMPKzuZ7YuLTGdtA8WeDke5cQ9ymPAtkbM19wU O34Kfoa8Tm+eu+lmiPR4F41LFsBWnPId1eEnuNFa6xeelVhhebyWUc+CquBQySTIUf 9Vh6SKzsH5hUUou9ueAZgSfTcm8rAW4d6yoFhXfE= Date: Thu, 04 Feb 2021 18:32:45 -0800 From: Andrew Morton To: akpm@linux-foundation.org, alex.shi@linux.alibaba.com, hannes@cmpxchg.org, linmiaohe@huawei.com, linux-mm@kvack.org, longman@redhat.com, mhocko@suse.com, mm-commits@vger.kernel.org, smuchun@gmail.com, stable@vger.kernel.org, torvalds@linux-foundation.org, willy@infradead.org Subject: [patch 13/18] mm/filemap: add missing mem_cgroup_uncharge() to __add_to_page_cache_locked() Message-ID: <20210205023245.2MSWh6RsL%akpm@linux-foundation.org> In-Reply-To: <20210204183135.e123f0d6027529f2cf500cf2@linux-foundation.org> User-Agent: s-nail v14.8.16 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Waiman Long Subject: mm/filemap: add missing mem_cgroup_uncharge() to __add_to_page_cache_locked() commit 3fea5a499d57 ("mm: memcontrol: convert page cache to a new mem_cgroup_charge() API") introduced a bug in __add_to_page_cache_locked() causing the following splat: [ 1570.068330] page dumped because: VM_BUG_ON_PAGE(page_memcg(page)) [ 1570.068333] pages's memcg:ffff8889a4116000 [ 1570.068343] ------------[ cut here ]------------ [ 1570.068346] kernel BUG at mm/memcontrol.c:2924! [ 1570.068355] invalid opcode: 0000 [#1] SMP KASAN PTI [ 1570.068359] CPU: 35 PID: 12345 Comm: cat Tainted: G S W I 5.11.0-rc4-debug+ #1 [ 1570.068363] Hardware name: HP HP Z8 G4 Workstation/81C7, BIOS P60 v01.25 12/06/2017 [ 1570.068365] RIP: 0010:commit_charge+0xf4/0x130 : [ 1570.068375] RSP: 0018:ffff8881b38d70e8 EFLAGS: 00010286 [ 1570.068379] RAX: 0000000000000000 RBX: ffffea00260ddd00 RCX: 0000000000000027 [ 1570.068382] RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffff88907ebe05a8 [ 1570.068384] RBP: ffffea00260ddd00 R08: ffffed120fd7c0b6 R09: ffffed120fd7c0b6 [ 1570.068386] R10: ffff88907ebe05ab R11: ffffed120fd7c0b5 R12: ffffea00260ddd38 [ 1570.068389] R13: ffff8889a4116000 R14: ffff8889a4116000 R15: 0000000000000001 [ 1570.068391] FS: 00007ff039638680(0000) GS:ffff88907ea00000(0000) knlGS:0000000000000000 [ 1570.068394] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 1570.068396] CR2: 00007f36f354cc20 CR3: 00000008a0126006 CR4: 00000000007706e0 [ 1570.068398] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 1570.068400] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 1570.068402] PKRU: 55555554 [ 1570.068404] Call Trace: [ 1570.068407] mem_cgroup_charge+0x175/0x770 [ 1570.068413] __add_to_page_cache_locked+0x712/0xad0 [ 1570.068439] add_to_page_cache_lru+0xc5/0x1f0 [ 1570.068461] cachefiles_read_or_alloc_pages+0x895/0x2e10 [cachefiles] [ 1570.068524] __fscache_read_or_alloc_pages+0x6c0/0xa00 [fscache] [ 1570.068540] __nfs_readpages_from_fscache+0x16d/0x630 [nfs] [ 1570.068585] nfs_readpages+0x24e/0x540 [nfs] [ 1570.068693] read_pages+0x5b1/0xc40 [ 1570.068711] page_cache_ra_unbounded+0x460/0x750 [ 1570.068729] generic_file_buffered_read_get_pages+0x290/0x1710 [ 1570.068756] generic_file_buffered_read+0x2a9/0xc30 [ 1570.068832] nfs_file_read+0x13f/0x230 [nfs] [ 1570.068872] new_sync_read+0x3af/0x610 [ 1570.068901] vfs_read+0x339/0x4b0 [ 1570.068909] ksys_read+0xf1/0x1c0 [ 1570.068920] do_syscall_64+0x33/0x40 [ 1570.068926] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 1570.068930] RIP: 0033:0x7ff039135595 Before that commit, there was a try_charge() and commit_charge() in __add_to_page_cache_locked(). These 2 separated charge functions were replaced by a single mem_cgroup_charge(). However, it forgot to add a matching mem_cgroup_uncharge() when the xarray insertion failed with the page released back to the pool. Fix this by adding a mem_cgroup_uncharge() call when insertion error happens. Link: https://lkml.kernel.org/r/20210125042441.20030-1-longman@redhat.com Fixes: 3fea5a499d57 ("mm: memcontrol: convert page cache to a new mem_cgroup_charge() API") Signed-off-by: Waiman Long Reviewed-by: Alex Shi Acked-by: Johannes Weiner Cc: Matthew Wilcox Cc: Miaohe Lin Cc: Muchun Song Cc: Michal Hocko Cc: Signed-off-by: Andrew Morton --- mm/filemap.c | 4 ++++ 1 file changed, 4 insertions(+) --- a/mm/filemap.c~mm-filemap-adding-missing-mem_cgroup_uncharge-to-__add_to_page_cache_locked +++ a/mm/filemap.c @@ -835,6 +835,7 @@ noinline int __add_to_page_cache_locked( XA_STATE(xas, &mapping->i_pages, offset); int huge = PageHuge(page); int error; + bool charged = false; VM_BUG_ON_PAGE(!PageLocked(page), page); VM_BUG_ON_PAGE(PageSwapBacked(page), page); @@ -848,6 +849,7 @@ noinline int __add_to_page_cache_locked( error = mem_cgroup_charge(page, current->mm, gfp); if (error) goto error; + charged = true; } gfp &= GFP_RECLAIM_MASK; @@ -896,6 +898,8 @@ unlock: if (xas_error(&xas)) { error = xas_error(&xas); + if (charged) + mem_cgroup_uncharge(page); goto error; }