From patchwork Wed Apr 27 19:00:35 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrew Morton X-Patchwork-Id: 567772 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id F377BC433FE for ; Wed, 27 Apr 2022 19:08:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232502AbiD0TLf (ORCPT ); Wed, 27 Apr 2022 15:11:35 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44348 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232727AbiD0TLZ (ORCPT ); Wed, 27 Apr 2022 15:11:25 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A719E887AF; Wed, 27 Apr 2022 12:00:39 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id C190BB8292A; Wed, 27 Apr 2022 19:00:37 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7262CC385A9; Wed, 27 Apr 2022 19:00:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1651086036; bh=vAWIq7IG0efF42ABjeR3sG4vAPsZ7lWpjgWQ9MgBLUM=; h=Date:To:From:Subject:From; b=xH6aCY7u4x5roMR9H1mK40K7iMqgKcy/L8uCMrokEXONY5qTa8br++AHgogCyKpWB onlhQn1ownvQeyRJbccMbFViUnTZ4uXZzIb9RCII5s0YaKJMista50tDS9YZ4bwLCT kronxQxQjJS22218GbNlgfwKEmTnx8im19Dvnw64= Date: Wed, 27 Apr 2022 12:00:35 -0700 To: mm-commits@vger.kernel.org, stable@vger.kernel.org, shy828301@gmail.com, naoya.horiguchi@nec.com, lkp@intel.com, xuyu@linux.alibaba.com, akpm@linux-foundation.org From: Andrew Morton Subject: + mm-huge_memory-do-not-overkill-when-splitting-huge_zero_page.patch added to -mm tree Message-Id: <20220427190036.7262CC385A9@smtp.kernel.org> Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org The patch titled Subject: mm/huge_memory: do not overkill when splitting huge_zero_page has been added to the -mm tree. Its filename is mm-huge_memory-do-not-overkill-when-splitting-huge_zero_page.patch This patch should soon appear at https://ozlabs.org/~akpm/mmots/broken-out/mm-huge_memory-do-not-overkill-when-splitting-huge_zero_page.patch and later at https://ozlabs.org/~akpm/mmotm/broken-out/mm-huge_memory-do-not-overkill-when-splitting-huge_zero_page.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Xu Yu Subject: mm/huge_memory: do not overkill when splitting huge_zero_page Kernel panic when injecting memory_failure for the global huge_zero_page, when CONFIG_DEBUG_VM is enabled, as follows. Injecting memory failure for pfn 0x109ff9 at process virtual address 0x20ff9000 page:00000000fb053fc3 refcount:2 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x109e00 head:00000000fb053fc3 order:9 compound_mapcount:0 compound_pincount:0 flags: 0x17fffc000010001(locked|head|node=0|zone=2|lastcpupid=0x1ffff) raw: 017fffc000010001 0000000000000000 dead000000000122 0000000000000000 raw: 0000000000000000 0000000000000000 00000002ffffffff 0000000000000000 page dumped because: VM_BUG_ON_PAGE(is_huge_zero_page(head)) ------------[ cut here ]------------ kernel BUG at mm/huge_memory.c:2499! invalid opcode: 0000 [#1] PREEMPT SMP PTI CPU: 6 PID: 553 Comm: split_bug Not tainted 5.18.0-rc1+ #11 Hardware name: Alibaba Cloud Alibaba Cloud ECS, BIOS 3288b3c 04/01/2014 RIP: 0010:split_huge_page_to_list+0x66a/0x880 Code: 84 9b fb ff ff 48 8b 7c 24 08 31 f6 e8 9f 5d 2a 00 b8 b8 02 00 00 e9 e8 fb ff ff 48 c7 c6 e8 47 3c 82 4c b RSP: 0018:ffffc90000dcbdf8 EFLAGS: 00010246 RAX: 000000000000003c RBX: 0000000000000001 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff823e4c4f RDI: 00000000ffffffff RBP: ffff88843fffdb40 R08: 0000000000000000 R09: 00000000fffeffff R10: ffffc90000dcbc48 R11: ffffffff82d68448 R12: ffffea0004278000 R13: ffffffff823c6203 R14: 0000000000109ff9 R15: ffffea000427fe40 FS: 00007fc375a26740(0000) GS:ffff88842fd80000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fc3757c9290 CR3: 0000000102174006 CR4: 00000000003706e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: try_to_split_thp_page+0x3a/0x130 memory_failure+0x128/0x800 madvise_inject_error.cold+0x8b/0xa1 __x64_sys_madvise+0x54/0x60 do_syscall_64+0x35/0x80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7fc3754f8bf9 Code: 01 00 48 81 c4 80 00 00 00 e9 f1 fe ff ff 0f 1f 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 8 RSP: 002b:00007ffeda93a1d8 EFLAGS: 00000217 ORIG_RAX: 000000000000001c RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fc3754f8bf9 RDX: 0000000000000064 RSI: 0000000000003000 RDI: 0000000020ff9000 RBP: 00007ffeda93a200 R08: 0000000000000000 R09: 0000000000000000 R10: 00000000ffffffff R11: 0000000000000217 R12: 0000000000400490 R13: 00007ffeda93a2e0 R14: 0000000000000000 R15: 0000000000000000 We think that raising BUG is overkilling for splitting huge_zero_page, the huge_zero_page can't be met from normal paths other than memory failure, but memory failure is a valid caller. So we tend to replace the BUG to WARN + returning -EBUSY, and thus the panic above won't happen again. Link: https://lkml.kernel.org/r/f35f8b97377d5d3ede1bc5ac3114da888c57cbce.1651052574.git.xuyu@linux.alibaba.com Fixes: d173d5417fb ("mm/memory-failure.c: skip huge_zero_page in memory_failure()") Fixes: 6a46079cf57a ("HWPOISON: The high level memory error handler in the VM v7") Signed-off-by: Xu Yu Suggested-by: Yang Shi Reported-by: kernel test robot Reviewed-by: Naoya Horiguchi Cc: Signed-off-by: Andrew Morton --- mm/huge_memory.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) --- a/mm/huge_memory.c~mm-huge_memory-do-not-overkill-when-splitting-huge_zero_page +++ a/mm/huge_memory.c @@ -2495,11 +2495,16 @@ int split_huge_page_to_list(struct page struct address_space *mapping = NULL; int extra_pins, ret; pgoff_t end; + bool is_hzp; - VM_BUG_ON_PAGE(is_huge_zero_page(head), head); VM_BUG_ON_PAGE(!PageLocked(head), head); VM_BUG_ON_PAGE(!PageCompound(head), head); + is_hzp = is_huge_zero_page(head); + VM_WARN_ON_ONCE_PAGE(is_hzp, head); + if (is_hzp) + return -EBUSY; + if (PageWriteback(head)) return -EBUSY;