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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 38B5FC433F5 for ; Mon, 1 Nov 2021 09:46:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1DC61610E5 for ; Mon, 1 Nov 2021 09:46:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233430AbhKAJtY (ORCPT ); Mon, 1 Nov 2021 05:49:24 -0400 Received: from mail.kernel.org ([198.145.29.99]:47844 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234412AbhKAJom (ORCPT ); Mon, 1 Nov 2021 05:44:42 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 198F361213; Mon, 1 Nov 2021 09:29:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1635758977; bh=WgnmWnMAOoBzmEdFoSQeI52A+DyGa7ZgAWXujZIJStM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=QyQ+M52VLLw62OZKSTgsiKi6X5uLPvhZxtpE7J4nx/t43EZYKisJMpGKQMwtZCuEN LiQ5hG0d5ZwBJwRInWc533oQkqWT75A2w++MQwtSSb9A7jBRCxpuD38t1xZQnotz2J CGqWySb7mX6xj4O0D6tHolLs+V2PiuiHKQi9RfU8= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Rongwei Wang , Xu Yu , Yang Shi , "Matthew Wilcox (Oracle)" , "Kirill A. Shutemov" , Song Liu , William Kucharski , Hugh Dickins , Mike Kravetz , Andrew Morton , Linus Torvalds Subject: [PATCH 5.14 035/125] mm, thp: bail out early in collapse_file for writeback page Date: Mon, 1 Nov 2021 10:16:48 +0100 Message-Id: <20211101082539.807637650@linuxfoundation.org> X-Mailer: git-send-email 2.33.1 In-Reply-To: <20211101082533.618411490@linuxfoundation.org> References: <20211101082533.618411490@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Rongwei Wang commit 74c42e1baacf206338b1dd6b6199ac964512b5bb upstream. Currently collapse_file does not explicitly check PG_writeback, instead, page_has_private and try_to_release_page are used to filter writeback pages. This does not work for xfs with blocksize equal to or larger than pagesize, because in such case xfs has no page->private. This makes collapse_file bail out early for writeback page. Otherwise, xfs end_page_writeback will panic as follows. page:fffffe00201bcc80 refcount:0 mapcount:0 mapping:ffff0003f88c86a8 index:0x0 pfn:0x84ef32 aops:xfs_address_space_operations [xfs] ino:30000b7 dentry name:"libtest.so" flags: 0x57fffe0000008027(locked|referenced|uptodate|active|writeback) raw: 57fffe0000008027 ffff80001b48bc28 ffff80001b48bc28 ffff0003f88c86a8 raw: 0000000000000000 0000000000000000 00000000ffffffff ffff0000c3e9a000 page dumped because: VM_BUG_ON_PAGE(((unsigned int) page_ref_count(page) + 127u <= 127u)) page->mem_cgroup:ffff0000c3e9a000 ------------[ cut here ]------------ kernel BUG at include/linux/mm.h:1212! Internal error: Oops - BUG: 0 [#1] SMP Modules linked in: BUG: Bad page state in process khugepaged pfn:84ef32 xfs(E) page:fffffe00201bcc80 refcount:0 mapcount:0 mapping:0 index:0x0 pfn:0x84ef32 libcrc32c(E) rfkill(E) aes_ce_blk(E) crypto_simd(E) ... CPU: 25 PID: 0 Comm: swapper/25 Kdump: loaded Tainted: ... pstate: 60400005 (nZCv daif +PAN -UAO -TCO BTYPE=--) Call trace: end_page_writeback+0x1c0/0x214 iomap_finish_page_writeback+0x13c/0x204 iomap_finish_ioend+0xe8/0x19c iomap_writepage_end_bio+0x38/0x50 bio_endio+0x168/0x1ec blk_update_request+0x278/0x3f0 blk_mq_end_request+0x34/0x15c virtblk_request_done+0x38/0x74 [virtio_blk] blk_done_softirq+0xc4/0x110 __do_softirq+0x128/0x38c __irq_exit_rcu+0x118/0x150 irq_exit+0x1c/0x30 __handle_domain_irq+0x8c/0xf0 gic_handle_irq+0x84/0x108 el1_irq+0xcc/0x180 arch_cpu_idle+0x18/0x40 default_idle_call+0x4c/0x1a0 cpuidle_idle_call+0x168/0x1e0 do_idle+0xb4/0x104 cpu_startup_entry+0x30/0x9c secondary_start_kernel+0x104/0x180 Code: d4210000 b0006161 910c8021 94013f4d (d4210000) ---[ end trace 4a88c6a074082f8c ]--- Kernel panic - not syncing: Oops - BUG: Fatal exception in interrupt Link: https://lkml.kernel.org/r/20211022023052.33114-1-rongwei.wang@linux.alibaba.com Fixes: 99cb0dbd47a1 ("mm,thp: add read-only THP support for (non-shmem) FS") Signed-off-by: Rongwei Wang Signed-off-by: Xu Yu Suggested-by: Yang Shi Reviewed-by: Matthew Wilcox (Oracle) Reviewed-by: Yang Shi Acked-by: Kirill A. Shutemov Cc: Song Liu Cc: William Kucharski Cc: Hugh Dickins Cc: Mike Kravetz Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- mm/khugepaged.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -1763,6 +1763,10 @@ static void collapse_file(struct mm_stru filemap_flush(mapping); result = SCAN_FAIL; goto xa_unlocked; + } else if (PageWriteback(page)) { + xas_unlock_irq(&xas); + result = SCAN_FAIL; + goto xa_unlocked; } else if (trylock_page(page)) { get_page(page); xas_unlock_irq(&xas); @@ -1798,7 +1802,8 @@ static void collapse_file(struct mm_stru goto out_unlock; } - if (!is_shmem && PageDirty(page)) { + if (!is_shmem && (PageDirty(page) || + PageWriteback(page))) { /* * khugepaged only works on read-only fd, so this * page is dirty because it hasn't been flushed