From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2B43C1D0E01; Wed, 2 Oct 2024 13:43:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727876599; cv=none; b=cbvYb7xWcdVKZKOTQ10MnkIU5AocEPm9NkebZRgy42BQskiEuLtBB2ZBfZjO019HszAqQLEV8G25JfjgHvEuaUobcRqLGAmVWVEPQhz/hAUKSq9/KWgZTSdmSuPNwjYcoYi/fqmds/WxG7mNxeol5WPte+eYdQclgdsQuSQI5AY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727876599; c=relaxed/simple; bh=P+vbVypkIndtbl+jZ4+FaEr5tBKz+1PNi1yi/XX9m+4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=HrRWqIeK60akorkSRF053TGr26st3hL6moFiTvHUdN81qSg/ysPsIr6eLmOBg26sZ5uM1QnAmJuqFgHe3KDMgYxEXHqTfo+i/wxVeE8vpz5kYU+1+YWfH7bRxuiluubHhqwKcDFkavqOfQooWyMhMV4KyJmzlbtCGHH/iiBr/eU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=0tNjeGXK; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="0tNjeGXK" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3F8FBC4CEC5; Wed, 2 Oct 2024 13:43:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1727876597; bh=P+vbVypkIndtbl+jZ4+FaEr5tBKz+1PNi1yi/XX9m+4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=0tNjeGXKmwnuAX3NsnLSlzhfCBvYAT/ENfWAMyLUsbuBBBF+9nAzCCiGZ+jrryaC7 nIc0sPTtK1Vj5kDkteoxYVSQRm8LDKgQEQKVCshU+Z4nQ6bEEOthvvEh4hrIo1GbN+ DlWtG5ad/NWHkwzZUAiULZB1nMH/8AtcnkU6ovpw= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Jeongjun Park , syzbot , David Hildenbrand , Kefeng Wang , Matthew Wilcox , Zi Yan , Andrew Morton Subject: [PATCH 6.11 499/695] mm: migrate: annotate data-race in migrate_folio_unmap() Date: Wed, 2 Oct 2024 14:58:17 +0200 Message-ID: <20241002125842.395408026@linuxfoundation.org> X-Mailer: git-send-email 2.46.2 In-Reply-To: <20241002125822.467776898@linuxfoundation.org> References: <20241002125822.467776898@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.11-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jeongjun Park commit 8001070cfbec5cd4ea00b8b48ea51df91122f265 upstream. I found a report from syzbot [1] This report shows that the value can be changed, but in reality, the value of __folio_set_movable() cannot be changed because it holds the folio refcount. Therefore, it is appropriate to add an annotate to make KCSAN ignore that data-race. [1] ================================================================== BUG: KCSAN: data-race in __filemap_remove_folio / migrate_pages_batch write to 0xffffea0004b81dd8 of 8 bytes by task 6348 on cpu 0: page_cache_delete mm/filemap.c:153 [inline] __filemap_remove_folio+0x1ac/0x2c0 mm/filemap.c:233 filemap_remove_folio+0x6b/0x1f0 mm/filemap.c:265 truncate_inode_folio+0x42/0x50 mm/truncate.c:178 shmem_undo_range+0x25b/0xa70 mm/shmem.c:1028 shmem_truncate_range mm/shmem.c:1144 [inline] shmem_evict_inode+0x14d/0x530 mm/shmem.c:1272 evict+0x2f0/0x580 fs/inode.c:731 iput_final fs/inode.c:1883 [inline] iput+0x42a/0x5b0 fs/inode.c:1909 dentry_unlink_inode+0x24f/0x260 fs/dcache.c:412 __dentry_kill+0x18b/0x4c0 fs/dcache.c:615 dput+0x5c/0xd0 fs/dcache.c:857 __fput+0x3fb/0x6d0 fs/file_table.c:439 ____fput+0x1c/0x30 fs/file_table.c:459 task_work_run+0x13a/0x1a0 kernel/task_work.c:228 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] exit_to_user_mode_loop kernel/entry/common.c:114 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0xbe/0x130 kernel/entry/common.c:218 do_syscall_64+0xd6/0x1c0 arch/x86/entry/common.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f read to 0xffffea0004b81dd8 of 8 bytes by task 6342 on cpu 1: __folio_test_movable include/linux/page-flags.h:699 [inline] migrate_folio_unmap mm/migrate.c:1199 [inline] migrate_pages_batch+0x24c/0x1940 mm/migrate.c:1797 migrate_pages_sync mm/migrate.c:1963 [inline] migrate_pages+0xff1/0x1820 mm/migrate.c:2072 do_mbind mm/mempolicy.c:1390 [inline] kernel_mbind mm/mempolicy.c:1533 [inline] __do_sys_mbind mm/mempolicy.c:1607 [inline] __se_sys_mbind+0xf76/0x1160 mm/mempolicy.c:1603 __x64_sys_mbind+0x78/0x90 mm/mempolicy.c:1603 x64_sys_call+0x2b4d/0x2d60 arch/x86/include/generated/asm/syscalls_64.h:238 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f value changed: 0xffff888127601078 -> 0x0000000000000000 Link: https://lkml.kernel.org/r/20240924130053.107490-1-aha310510@gmail.com Fixes: 7e2a5e5ab217 ("mm: migrate: use __folio_test_movable()") Signed-off-by: Jeongjun Park Reported-by: syzbot Acked-by: David Hildenbrand Cc: Kefeng Wang Cc: Matthew Wilcox Cc: Zi Yan Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman --- mm/migrate.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/mm/migrate.c +++ b/mm/migrate.c @@ -1118,7 +1118,7 @@ static int migrate_folio_unmap(new_folio int rc = -EAGAIN; int old_page_state = 0; struct anon_vma *anon_vma = NULL; - bool is_lru = !__folio_test_movable(src); + bool is_lru = data_race(!__folio_test_movable(src)); bool locked = false; bool dst_locked = false;