From patchwork Mon Oct 25 09:21:33 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Rongwei Wang X-Patchwork-Id: 12581119 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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 67114C433EF for ; Mon, 25 Oct 2021 09:21:46 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 02CB360F92 for ; Mon, 25 Oct 2021 09:21:45 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 02CB360F92 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id BD1E46B0075; Mon, 25 Oct 2021 05:21:44 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id B7FB280007; Mon, 25 Oct 2021 05:21:44 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A6F366B007B; Mon, 25 Oct 2021 05:21:44 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0113.hostedemail.com [216.40.44.113]) by kanga.kvack.org (Postfix) with ESMTP id 9B0A76B0075 for ; Mon, 25 Oct 2021 05:21:44 -0400 (EDT) Received: from smtpin38.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 5DC4F8249980 for ; Mon, 25 Oct 2021 09:21:44 +0000 (UTC) X-FDA: 78734417328.38.5A45934 Received: from out30-42.freemail.mail.aliyun.com (out30-42.freemail.mail.aliyun.com [115.124.30.42]) by imf05.hostedemail.com (Postfix) with ESMTP id D79365084D57 for ; Mon, 25 Oct 2021 09:21:33 +0000 (UTC) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R701e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04423;MF=rongwei.wang@linux.alibaba.com;NM=1;PH=DS;RN=9;SR=0;TI=SMTPD_---0UtZwp5E_1635153697; Received: from localhost.localdomain(mailfrom:rongwei.wang@linux.alibaba.com fp:SMTPD_---0UtZwp5E_1635153697) by smtp.aliyun-inc.com(127.0.0.1); Mon, 25 Oct 2021 17:21:39 +0800 From: Rongwei Wang To: akpm@linux-foundation.org, willy@infradead.org, song@kernel.org, william.kucharski@oracle.com, hughd@google.com, shy828301@gmail.com Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: [PATCH 1/2] mm, thp: lock filemap when truncating page cache Date: Mon, 25 Oct 2021 17:21:33 +0800 Message-Id: <20211025092134.18562-2-rongwei.wang@linux.alibaba.com> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20211025092134.18562-1-rongwei.wang@linux.alibaba.com> References: <20211025092134.18562-1-rongwei.wang@linux.alibaba.com> MIME-Version: 1.0 X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: D79365084D57 X-Stat-Signature: hoibs68kw8co5u8btryu348hbt6djshh Authentication-Results: imf05.hostedemail.com; dkim=none; spf=pass (imf05.hostedemail.com: domain of rongwei.wang@linux.alibaba.com designates 115.124.30.42 as permitted sender) smtp.mailfrom=rongwei.wang@linux.alibaba.com; dmarc=pass (policy=none) header.from=alibaba.com X-HE-Tag: 1635153693-318488 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: Transparent huge page has supported read-only non-shmem files. The file- backed THP is collapsed by khugepaged and truncated when written (for shared libraries). However, there is a race when multiple writers truncate the same page cache concurrently. In that case, subpage(s) of file THP can be revealed by find_get_entry in truncate_inode_pages_range, which will trigger PageTail BUG_ON in truncate_inode_page, as follows. page:000000009e420ff2 refcount:1 mapcount:0 mapping:0000000000000000 index:0x7ff pfn:0x50c3ff head:0000000075ff816d order:9 compound_mapcount:0 compound_pincount:0 flags: 0x37fffe0000010815(locked|uptodate|lru|arch_1|head) raw: 37fffe0000000000 fffffe0013108001 dead000000000122 dead000000000400 raw: 0000000000000001 0000000000000000 00000000ffffffff 0000000000000000 head: 37fffe0000010815 fffffe001066bd48 ffff000404183c20 0000000000000000 head: 0000000000000600 0000000000000000 00000001ffffffff ffff000c0345a000 page dumped because: VM_BUG_ON_PAGE(PageTail(page)) ------------[ cut here ]------------ kernel BUG at mm/truncate.c:213! Internal error: Oops - BUG: 0 [#1] SMP Modules linked in: xfs(E) libcrc32c(E) rfkill(E) ... CPU: 14 PID: 11394 Comm: check_madvise_d Kdump: ... Hardware name: ECS, BIOS 0.0.0 02/06/2015 pstate: 60400005 (nZCv daif +PAN -UAO -TCO BTYPE=--) pc : truncate_inode_page+0x64/0x70 lr : truncate_inode_page+0x64/0x70 sp : ffff80001b60b900 x29: ffff80001b60b900 x28: 00000000000007ff x27: ffff80001b60b9a0 x26: 0000000000000000 x25: 000000000000000f x24: ffff80001b60b9a0 x23: ffff80001b60ba18 x22: ffff0001e0999ea8 x21: ffff0000c21db300 x20: ffffffffffffffff x19: fffffe001310ffc0 x18: 0000000000000020 x17: 0000000000000000 x16: 0000000000000000 x15: ffff0000c21db960 x14: 3030306666666620 x13: 6666666666666666 x12: 3130303030303030 x11: ffff8000117b69b8 x10: 00000000ffff8000 x9 : ffff80001012690c x8 : 0000000000000000 x7 : ffff8000114f69b8 x6 : 0000000000017ffd x5 : ffff0007fffbcbc8 x4 : ffff80001b60b5c0 x3 : 0000000000000001 x2 : 0000000000000000 x1 : 0000000000000000 x0 : 0000000000000000 Call trace: truncate_inode_page+0x64/0x70 truncate_inode_pages_range+0x550/0x7e4 truncate_pagecache+0x58/0x80 do_dentry_open+0x1e4/0x3c0 vfs_open+0x38/0x44 do_open+0x1f0/0x310 path_openat+0x114/0x1dc do_filp_open+0x84/0x134 do_sys_openat2+0xbc/0x164 __arm64_sys_openat+0x74/0xc0 el0_svc_common.constprop.0+0x88/0x220 do_el0_svc+0x30/0xa0 el0_svc+0x20/0x30 el0_sync_handler+0x1a4/0x1b0 el0_sync+0x180/0x1c0 Code: aa0103e0 900061e1 910ec021 9400d300 (d4210000) ---[ end trace f70cdb42cb7c2d42 ]--- Kernel panic - not syncing: Oops - BUG: Fatal exception This patch mainly to lock filemap when one enter truncate_pagecache(), avoiding truncating the same page cache concurrently. Fixes: eb6ecbed0aa2 ("mm, thp: relax the VM_DENYWRITE constraint on file-backed THPs") Cc: Suggested-by: Matthew Wilcox (Oracle) Tested-by: Song Liu Signed-off-by: Xu Yu Signed-off-by: Rongwei Wang --- fs/open.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/fs/open.c b/fs/open.c index a7f6cab81267..e73bf88e5060 100644 --- a/fs/open.c +++ b/fs/open.c @@ -856,8 +856,11 @@ static int do_dentry_open(struct file *f, * of THPs into the page cache will fail. */ smp_mb(); - if (filemap_nr_thps(inode->i_mapping)) + if (filemap_nr_thps(inode->i_mapping)) { + filemap_invalidate_lock(inode->i_mapping); truncate_pagecache(inode, 0); + filemap_invalidate_unlock(inode->i_mapping); + } } return 0; From patchwork Mon Oct 25 09:21:34 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Rongwei Wang X-Patchwork-Id: 12581121 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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 416E5C433EF for ; Mon, 25 Oct 2021 09:21:48 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id E601A60E97 for ; Mon, 25 Oct 2021 09:21:47 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org E601A60E97 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id 42FD280008; Mon, 25 Oct 2021 05:21:45 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 3DF2E80007; Mon, 25 Oct 2021 05:21:45 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 2D04180008; Mon, 25 Oct 2021 05:21:45 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0047.hostedemail.com [216.40.44.47]) by kanga.kvack.org (Postfix) with ESMTP id 2133180007 for ; Mon, 25 Oct 2021 05:21:45 -0400 (EDT) Received: from smtpin31.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id D30868249980 for ; Mon, 25 Oct 2021 09:21:44 +0000 (UTC) X-FDA: 78734417328.31.05E043F Received: from out30-57.freemail.mail.aliyun.com (out30-57.freemail.mail.aliyun.com [115.124.30.57]) by imf15.hostedemail.com (Postfix) with ESMTP id 38EACD00009F for ; Mon, 25 Oct 2021 09:21:37 +0000 (UTC) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R731e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04357;MF=rongwei.wang@linux.alibaba.com;NM=1;PH=DS;RN=9;SR=0;TI=SMTPD_---0UtZwp5E_1635153697; Received: from localhost.localdomain(mailfrom:rongwei.wang@linux.alibaba.com fp:SMTPD_---0UtZwp5E_1635153697) by smtp.aliyun-inc.com(127.0.0.1); Mon, 25 Oct 2021 17:21:39 +0800 From: Rongwei Wang To: akpm@linux-foundation.org, willy@infradead.org, song@kernel.org, william.kucharski@oracle.com, hughd@google.com, shy828301@gmail.com Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: [PATCH 2/2] mm, thp: fix incorrect unmap behavior for private pages Date: Mon, 25 Oct 2021 17:21:34 +0800 Message-Id: <20211025092134.18562-3-rongwei.wang@linux.alibaba.com> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20211025092134.18562-1-rongwei.wang@linux.alibaba.com> References: <20211025092134.18562-1-rongwei.wang@linux.alibaba.com> MIME-Version: 1.0 X-Rspamd-Queue-Id: 38EACD00009F Authentication-Results: imf15.hostedemail.com; dkim=none; spf=pass (imf15.hostedemail.com: domain of rongwei.wang@linux.alibaba.com designates 115.124.30.57 as permitted sender) smtp.mailfrom=rongwei.wang@linux.alibaba.com; dmarc=pass (policy=none) header.from=alibaba.com X-Stat-Signature: opc1wg1fgwd5jy4zdooiaw39nzzyqway X-Rspamd-Server: rspam06 X-HE-Tag: 1635153697-52886 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: When truncating pagecache on file THP, the private pages of a process should not be unmapped mapping. This incorrect behavior on a dynamic shared libraries which will cause related processes to happen core dump. A simple test for a DSO (Prerequisite is the DSO mapped in file THP): int main(int argc, char *argv[]) { int fd; fd = open(argv[1], O_WRONLY); if (fd < 0) { perror("open"); } close(fd); return 0; } The test only to open a target DSO, and do nothing. But this operation will lead one or more process to happen core dump. This patch mainly to fix this bug. Fixes: eb6ecbed0aa2 ("mm, thp: relax the VM_DENYWRITE constraint on file-backed THPs") Cc: Tested-by: Xu Yu Signed-off-by: Rongwei Wang --- fs/open.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/fs/open.c b/fs/open.c index e73bf88e5060..f732fb94600c 100644 --- a/fs/open.c +++ b/fs/open.c @@ -857,8 +857,17 @@ static int do_dentry_open(struct file *f, */ smp_mb(); if (filemap_nr_thps(inode->i_mapping)) { + struct address_space *mapping = inode->i_mapping; + filemap_invalidate_lock(inode->i_mapping); - truncate_pagecache(inode, 0); + /* + * unmap_mapping_range just need to be called once + * here, because the private pages is not need to be + * unmapped mapping (e.g. data segment of dynamic + * shared libraries here). + */ + unmap_mapping_range(mapping, 0, 0, 0); + truncate_inode_pages(mapping, 0); filemap_invalidate_unlock(inode->i_mapping); } }