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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6FDD2C433FE for ; Mon, 7 Nov 2022 18:30:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232994AbiKGSaB (ORCPT ); Mon, 7 Nov 2022 13:30:01 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45740 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232981AbiKGS36 (ORCPT ); Mon, 7 Nov 2022 13:29:58 -0500 Received: from mail-io1-f69.google.com (mail-io1-f69.google.com [209.85.166.69]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DD2141902A for ; Mon, 7 Nov 2022 10:29:52 -0800 (PST) Received: by mail-io1-f69.google.com with SMTP id x21-20020a5d9455000000b006bc1172e639so7709488ior.18 for ; Mon, 07 Nov 2022 10:29:52 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=to:from:subject:message-id:date:mime-version:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=ILXgDeED0B9TieOZ1yhu4rMHPM18i/4CeVyvudKaPP8=; b=qtQ/wCHOJoF1kWYwTfCTSpDxqCFK85C+hiwcS7mwAdrVFUVT7p1motIXpzS/mWm2O+ R4A+fbivQjg+oIQfocFamQhRGOO0aSyO8GIzUdShDWYzpeJII3evN/m4Sr4PZJ820s20 D61mtPlPKLRK7pHPo9eM3l6OTLQ3nKcbpv5TrmbZQKUSiqENvsEhaXuHcKkn040noE86 3mDuyr8fxdo/6RR5d6TL1dzBfMW3mo62slWMMstPfnVMQMsT+UnwqElN8uQFT4sFwGkB wMj6o2f5pP63yBIYoKpiC6IEY9SJdzvFeNISqT0OU4rbQQLYU268dQq0e1yIV0QWiOU9 oeeg== X-Gm-Message-State: ACrzQf2chxNJ2fgt5HP2Cgx3aVBLt1WiV+D5KT70odB32JizlBOO/nN/ CG0SKN/m7n7tAlUPpHMQX3oCHGXYN8HQX8/dm+h5nVE2PigM X-Google-Smtp-Source: AMsMyM7oXP1WtFevwDBtmgOdu03qyjgu1zf89PWRBtzdXhD+z8wKRhMDmfNKPvkejJS5rNtI1TL6dZrntC/La9OdYtX7SgDhptMt MIME-Version: 1.0 X-Received: by 2002:a05:6638:264c:b0:375:2a59:683c with SMTP id n12-20020a056638264c00b003752a59683cmr29825763jat.232.1667845792271; Mon, 07 Nov 2022 10:29:52 -0800 (PST) Date: Mon, 07 Nov 2022 10:29:52 -0800 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <000000000000fd151d05ece59b42@google.com> Subject: [syzbot] possible deadlock in btrfs_search_slot From: syzbot To: clm@fb.com, dsterba@suse.com, josef@toxicpanda.com, linux-btrfs@vger.kernel.org, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org Hello, syzbot found the following issue on: HEAD commit: f0c4d9fc9cc9 Linux 6.1-rc4 git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=10d158fe880000 kernel config: https://syzkaller.appspot.com/x/.config?x=771b06c41e08f95b dashboard link: https://syzkaller.appspot.com/bug?extid=c06034aecf9f5eab1ac1 compiler: Debian clang version 13.0.1-++20220126092033+75e33f71c2da-1~exp1~20220126212112.63, GNU ld (GNU Binutils for Debian) 2.35.2 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/8c210d1cda58/disk-f0c4d9fc.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/ab3065e17b8b/vmlinux-f0c4d9fc.xz kernel image: https://storage.googleapis.com/syzbot-assets/739b786269f4/bzImage-f0c4d9fc.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+c06034aecf9f5eab1ac1@syzkaller.appspotmail.com ====================================================== WARNING: possible circular locking dependency detected 6.1.0-rc4-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.1/21431 is trying to acquire lock: ffff888028341e58 (&mm->mmap_lock#2){++++}-{3:3}, at: __might_fault+0x8f/0x110 mm/memory.c:5645 but task is already holding lock: ffff888020a77838 (btrfs-root-00){++++}-{3:3}, at: __btrfs_tree_read_lock fs/btrfs/locking.c:134 [inline] ffff888020a77838 (btrfs-root-00){++++}-{3:3}, at: btrfs_tree_read_lock fs/btrfs/locking.c:140 [inline] ffff888020a77838 (btrfs-root-00){++++}-{3:3}, at: btrfs_read_lock_root_node+0x2b4/0x400 fs/btrfs/locking.c:279 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (btrfs-root-00){++++}-{3:3}: lock_acquire+0x182/0x3c0 kernel/locking/lockdep.c:5668 down_read_nested+0x3c/0x50 kernel/locking/rwsem.c:1634 __btrfs_tree_read_lock fs/btrfs/locking.c:134 [inline] btrfs_tree_read_lock fs/btrfs/locking.c:140 [inline] btrfs_read_lock_root_node+0x2b4/0x400 fs/btrfs/locking.c:279 btrfs_search_slot_get_root fs/btrfs/ctree.c:1649 [inline] btrfs_search_slot+0x495/0x2fe0 fs/btrfs/ctree.c:1969 btrfs_insert_empty_items fs/btrfs/ctree.c:4103 [inline] btrfs_insert_empty_item fs/btrfs/ctree.h:3127 [inline] btrfs_insert_item+0x199/0x3b0 fs/btrfs/ctree.c:4132 btrfs_create_tree+0x7c9/0xc30 fs/btrfs/disk-io.c:1229 btrfs_create_free_space_tree+0x116/0x1160 fs/btrfs/free-space-tree.c:1169 btrfs_start_pre_rw_mount+0x4df/0x660 fs/btrfs/disk-io.c:3254 open_ctree+0x27e6/0x2d6d fs/btrfs/disk-io.c:3790 btrfs_fill_super+0x1c6/0x2d0 fs/btrfs/super.c:1461 btrfs_mount_root+0x885/0x9a0 fs/btrfs/super.c:1829 legacy_get_tree+0xea/0x180 fs/fs_context.c:610 vfs_get_tree+0x88/0x270 fs/super.c:1531 fc_mount fs/namespace.c:1043 [inline] vfs_kern_mount+0xc9/0x160 fs/namespace.c:1073 btrfs_mount+0x3d3/0xbb0 fs/btrfs/super.c:1889 legacy_get_tree+0xea/0x180 fs/fs_context.c:610 vfs_get_tree+0x88/0x270 fs/super.c:1531 do_new_mount+0x289/0xad0 fs/namespace.c:3040 do_mount fs/namespace.c:3383 [inline] __do_sys_mount fs/namespace.c:3591 [inline] __se_sys_mount+0x2d3/0x3c0 fs/namespace.c:3568 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd -> #2 (btrfs_trans_num_extwriters){++++}-{0:0}: lock_acquire+0x182/0x3c0 kernel/locking/lockdep.c:5668 join_transaction+0x19f/0xe60 fs/btrfs/transaction.c:299 start_transaction+0x6fb/0x1180 fs/btrfs/transaction.c:658 btrfs_commit_super+0x9a/0xd0 fs/btrfs/disk-io.c:4494 close_ctree+0x3a7/0xbde fs/btrfs/disk-io.c:4651 generic_shutdown_super+0x130/0x310 fs/super.c:492 kill_anon_super+0x36/0x60 fs/super.c:1086 btrfs_kill_super+0x3d/0x50 fs/btrfs/super.c:2441 deactivate_locked_super+0xa7/0xf0 fs/super.c:332 cleanup_mnt+0x494/0x520 fs/namespace.c:1186 task_work_run+0x243/0x300 kernel/task_work.c:179 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] exit_to_user_mode_loop+0x124/0x150 kernel/entry/common.c:171 exit_to_user_mode_prepare+0xb2/0x140 kernel/entry/common.c:203 __syscall_exit_to_user_mode_work kernel/entry/common.c:285 [inline] syscall_exit_to_user_mode+0x26/0x60 kernel/entry/common.c:296 do_syscall_64+0x49/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x63/0xcd -> #1 (btrfs_trans_num_writers){++++}-{0:0}: reacquire_held_locks+0x386/0x650 kernel/locking/lockdep.c:5193 __lock_release kernel/locking/lockdep.c:5382 [inline] lock_release+0x2e2/0x820 kernel/locking/lockdep.c:5688 percpu_up_read include/linux/percpu-rwsem.h:99 [inline] __sb_end_write include/linux/fs.h:1821 [inline] sb_end_intwrite+0x1e/0x1a0 include/linux/fs.h:1877 __btrfs_end_transaction+0x388/0x790 fs/btrfs/transaction.c:995 btrfs_dirty_inode+0x177/0x1c0 fs/btrfs/inode.c:6099 inode_update_time fs/inode.c:1871 [inline] touch_atime+0x315/0x630 fs/inode.c:1944 file_accessed include/linux/fs.h:2521 [inline] btrfs_file_mmap+0xbb/0x120 fs/btrfs/file.c:2333 call_mmap include/linux/fs.h:2196 [inline] mmap_region+0x10c1/0x1da0 mm/mmap.c:2625 do_mmap+0x8d9/0xf60 mm/mmap.c:1412 vm_mmap_pgoff+0x19e/0x2b0 mm/util.c:520 ksys_mmap_pgoff+0x48c/0x6d0 mm/mmap.c:1458 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd -> #0 (&mm->mmap_lock#2){++++}-{3:3}: check_prev_add kernel/locking/lockdep.c:3097 [inline] check_prevs_add kernel/locking/lockdep.c:3216 [inline] validate_chain+0x1898/0x6ae0 kernel/locking/lockdep.c:3831 __lock_acquire+0x1292/0x1f60 kernel/locking/lockdep.c:5055 lock_acquire+0x182/0x3c0 kernel/locking/lockdep.c:5668 __might_fault+0xb2/0x110 mm/memory.c:5646 _copy_to_user+0x26/0x130 lib/usercopy.c:29 copy_to_user include/linux/uaccess.h:169 [inline] btrfs_ioctl_get_subvol_rootref+0x8cf/0xa90 fs/btrfs/ioctl.c:3203 btrfs_ioctl+0xb7c/0xc10 fs/btrfs/ioctl.c:5556 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:870 [inline] __se_sys_ioctl+0xfb/0x170 fs/ioctl.c:856 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd other info that might help us debug this: Chain exists of: &mm->mmap_lock#2 --> btrfs_trans_num_extwriters --> btrfs-root-00 Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(btrfs-root-00); lock(btrfs_trans_num_extwriters); lock(btrfs-root-00); lock(&mm->mmap_lock#2); *** DEADLOCK *** 1 lock held by syz-executor.1/21431: #0: ffff888020a77838 (btrfs-root-00){++++}-{3:3}, at: __btrfs_tree_read_lock fs/btrfs/locking.c:134 [inline] #0: ffff888020a77838 (btrfs-root-00){++++}-{3:3}, at: btrfs_tree_read_lock fs/btrfs/locking.c:140 [inline] #0: ffff888020a77838 (btrfs-root-00){++++}-{3:3}, at: btrfs_read_lock_root_node+0x2b4/0x400 fs/btrfs/locking.c:279 stack backtrace: CPU: 1 PID: 21431 Comm: syz-executor.1 Not tainted 6.1.0-rc4-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1b1/0x28e lib/dump_stack.c:106 check_noncircular+0x2cc/0x390 kernel/locking/lockdep.c:2177 check_prev_add kernel/locking/lockdep.c:3097 [inline] check_prevs_add kernel/locking/lockdep.c:3216 [inline] validate_chain+0x1898/0x6ae0 kernel/locking/lockdep.c:3831 __lock_acquire+0x1292/0x1f60 kernel/locking/lockdep.c:5055 lock_acquire+0x182/0x3c0 kernel/locking/lockdep.c:5668 __might_fault+0xb2/0x110 mm/memory.c:5646 _copy_to_user+0x26/0x130 lib/usercopy.c:29 copy_to_user include/linux/uaccess.h:169 [inline] btrfs_ioctl_get_subvol_rootref+0x8cf/0xa90 fs/btrfs/ioctl.c:3203 btrfs_ioctl+0xb7c/0xc10 fs/btrfs/ioctl.c:5556 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:870 [inline] __se_sys_ioctl+0xfb/0x170 fs/ioctl.c:856 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7f1a4f28b5a9 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f1a4ffb1168 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f1a4f3ac050 RCX: 00007f1a4f28b5a9 RDX: 0000000020058480 RSI: 00000000d000943d RDI: 0000000000000005 RBP: 00007f1a4f2e67b0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffc4fbced1f R14: 00007f1a4ffb1300 R15: 0000000000022000 --- This report is generated by a bot. 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