possible deadlock in start

Kernel	Title	Repro	Count	Last	Reported	Patched	Status
linux-4.19	possible deadlock in start_transaction (2) btrfs	C	424	639d	738d	0/1	upstream: reported C repro on 2022/11/27 06:33
upstream	possible deadlock in start_transaction btrfs		2	1526d	1522d	0/28	auto-closed as invalid on 2021/01/28 08:05
linux-4.14	possible deadlock in start_transaction btrfs	syz	6	665d	707d	0/1	upstream: reported syz repro on 2022/12/27 19:04

BTRFS: device fsid f90cac8b-044b-4fa8-8bee-4b8d3da88dc2 devid 1 transid 7 /dev/loop1 BTRFS info (device loop1): disk space caching is enabled BTRFS info (device loop1): has skinny extents ====================================================== WARNING: possible circular locking dependency detected 4.19.211-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.1/9696 is trying to acquire lock: 00000000262f3290 (sb_internal#2){.+.+}, at: sb_start_intwrite include/linux/fs.h:1626 [inline] 00000000262f3290 (sb_internal#2){.+.+}, at: start_transaction+0xa37/0xf90 fs/btrfs/transaction.c:528 but task is already holding lock: 0000000043753794 (&mm->mmap_sem){++++}, at: vm_mmap_pgoff+0x152/0x200 mm/util.c:355 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #7 (&mm->mmap_sem){++++}: _copy_from_iter_full+0x256/0x7c0 lib/iov_iter.c:723 copy_from_iter_full include/linux/uio.h:124 [inline] skb_do_copy_data_nocache include/net/sock.h:1971 [inline] skb_add_data_nocache include/net/sock.h:1982 [inline] tcp_sendmsg_locked+0x194d/0x2f60 net/ipv4/tcp.c:1339 tcp_sendmsg+0x2b/0x40 net/ipv4/tcp.c:1462 inet_sendmsg+0x132/0x5a0 net/ipv4/af_inet.c:798 sock_sendmsg_nosec net/socket.c:651 [inline] sock_sendmsg+0xc3/0x120 net/socket.c:661 sock_write_iter+0x287/0x3c0 net/socket.c:966 call_write_iter include/linux/fs.h:1821 [inline] new_sync_write fs/read_write.c:474 [inline] __vfs_write+0x51b/0x770 fs/read_write.c:487 vfs_write+0x1f3/0x540 fs/read_write.c:549 ksys_write+0x12b/0x2a0 fs/read_write.c:599 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #6 (sk_lock-AF_INET){+.+.}: lock_sock include/net/sock.h:1512 [inline] inet_shutdown+0x7d/0x3a0 net/ipv4/af_inet.c:852 nbd_mark_nsock_dead+0xae/0x5b0 drivers/block/nbd.c:255 sock_shutdown+0x163/0x240 drivers/block/nbd.c:340 nbd_clear_sock drivers/block/nbd.c:1146 [inline] nbd_config_put+0x17a/0x870 drivers/block/nbd.c:1162 nbd_release+0xf4/0x170 drivers/block/nbd.c:1461 __blkdev_put+0x636/0x870 fs/block_dev.c:1819 blkdev_close+0x86/0xb0 fs/block_dev.c:1888 __fput+0x2ce/0x890 fs/file_table.c:278 task_work_run+0x148/0x1c0 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:193 [inline] exit_to_usermode_loop+0x251/0x2a0 arch/x86/entry/common.c:167 prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline] syscall_return_slowpath arch/x86/entry/common.c:271 [inline] do_syscall_64+0x538/0x620 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #5 (&nsock->tx_lock){+.+.}: sock_shutdown+0x156/0x240 drivers/block/nbd.c:339 nbd_clear_sock drivers/block/nbd.c:1146 [inline] nbd_config_put+0x17a/0x870 drivers/block/nbd.c:1162 nbd_release+0xf4/0x170 drivers/block/nbd.c:1461 __blkdev_put+0x636/0x870 fs/block_dev.c:1819 blkdev_close+0x86/0xb0 fs/block_dev.c:1888 __fput+0x2ce/0x890 fs/file_table.c:278 task_work_run+0x148/0x1c0 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:193 [inline] exit_to_usermode_loop+0x251/0x2a0 arch/x86/entry/common.c:167 prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline] syscall_return_slowpath arch/x86/entry/common.c:271 [inline] do_syscall_64+0x538/0x620 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #4 (&nbd->config_lock){+.+.}: nbd_open+0x2e2/0x6f0 drivers/block/nbd.c:1428 __blkdev_get+0x372/0x1480 fs/block_dev.c:1494 blkdev_get+0xb0/0x940 fs/block_dev.c:1627 blkdev_open+0x202/0x290 fs/block_dev.c:1788 do_dentry_open+0x4aa/0x1160 fs/open.c:796 do_last fs/namei.c:3421 [inline] path_openat+0x793/0x2df0 fs/namei.c:3537 do_filp_open+0x18c/0x3f0 fs/namei.c:3567 do_sys_open+0x3b3/0x520 fs/open.c:1085 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #3 (nbd_index_mutex){+.+.}: nbd_open+0x73/0x6f0 drivers/block/nbd.c:1415 __blkdev_get+0x372/0x1480 fs/block_dev.c:1494 blkdev_get+0xb0/0x940 fs/block_dev.c:1627 blkdev_open+0x202/0x290 fs/block_dev.c:1788 do_dentry_open+0x4aa/0x1160 fs/open.c:796 do_last fs/namei.c:3421 [inline] path_openat+0x793/0x2df0 fs/namei.c:3537 do_filp_open+0x18c/0x3f0 fs/namei.c:3567 do_sys_open+0x3b3/0x520 fs/open.c:1085 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #2 (&bdev->bd_mutex){+.+.}: blkdev_put+0x30/0x520 fs/block_dev.c:1839 btrfs_close_bdev fs/btrfs/volumes.c:1033 [inline] btrfs_close_one_device fs/btrfs/volumes.c:1057 [inline] close_fs_devices.part.0+0x24d/0x8e0 fs/btrfs/volumes.c:1085 close_fs_devices fs/btrfs/volumes.c:1117 [inline] btrfs_close_devices+0x95/0x1f0 fs/btrfs/volumes.c:1103 open_ctree+0x26b/0x61e0 fs/btrfs/disk-io.c:3326 btrfs_fill_super fs/btrfs/super.c:1209 [inline] btrfs_mount_root+0x12e5/0x1830 fs/btrfs/super.c:1613 mount_fs+0xa3/0x310 fs/super.c:1261 vfs_kern_mount.part.0+0x68/0x470 fs/namespace.c:961 vfs_kern_mount+0x3c/0x60 fs/namespace.c:951 btrfs_mount+0x23a/0xaa0 fs/btrfs/super.c:1681 mount_fs+0xa3/0x310 fs/super.c:1261 vfs_kern_mount.part.0+0x68/0x470 fs/namespace.c:961 vfs_kern_mount fs/namespace.c:951 [inline] do_new_mount fs/namespace.c:2492 [inline] do_mount+0x115c/0x2f50 fs/namespace.c:2822 ksys_mount+0xcf/0x130 fs/namespace.c:3038 __do_sys_mount fs/namespace.c:3052 [inline] __se_sys_mount fs/namespace.c:3049 [inline] __x64_sys_mount+0xba/0x150 fs/namespace.c:3049 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #1 (&fs_devs->device_list_mutex){+.+.}: btrfs_finish_chunk_alloc+0x27b/0xf90 fs/btrfs/volumes.c:4938 btrfs_create_pending_block_groups+0x242/0x590 fs/btrfs/extent-tree.c:10134 __btrfs_end_transaction+0x21a/0xb00 fs/btrfs/transaction.c:855 flush_space+0xa41/0xee0 fs/btrfs/extent-tree.c:4861 btrfs_async_reclaim_metadata_space+0x466/0x1050 fs/btrfs/extent-tree.c:4977 process_one_work+0x864/0x1570 kernel/workqueue.c:2153 worker_thread+0x64c/0x1130 kernel/workqueue.c:2296 kthread+0x33f/0x460 kernel/kthread.c:259 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 -> #0 (sb_internal#2){.+.+}: percpu_down_read_preempt_disable include/linux/percpu-rwsem.h:36 [inline] percpu_down_read include/linux/percpu-rwsem.h:59 [inline] __sb_start_write+0x6e/0x2a0 fs/super.c:1366 sb_start_intwrite include/linux/fs.h:1626 [inline] start_transaction+0xa37/0xf90 fs/btrfs/transaction.c:528 btrfs_dirty_inode+0xe3/0x210 fs/btrfs/inode.c:6165 btrfs_update_time+0x33b/0x3d0 fs/btrfs/inode.c:6207 update_time fs/inode.c:1675 [inline] touch_atime+0x23c/0x2a0 fs/inode.c:1746 file_accessed include/linux/fs.h:2123 [inline] btrfs_file_mmap+0x11b/0x160 fs/btrfs/file.c:2274 call_mmap include/linux/fs.h:1826 [inline] mmap_region+0xc94/0x16b0 mm/mmap.c:1757 do_mmap+0x8e8/0x1080 mm/mmap.c:1530 do_mmap_pgoff include/linux/mm.h:2329 [inline] vm_mmap_pgoff+0x197/0x200 mm/util.c:357 ksys_mmap_pgoff+0x298/0x5a0 mm/mmap.c:1580 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe other info that might help us debug this: Chain exists of: sb_internal#2 --> sk_lock-AF_INET --> &mm->mmap_sem Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&mm->mmap_sem); lock(sk_lock-AF_INET); lock(&mm->mmap_sem); lock(sb_internal#2); *** DEADLOCK *** 2 locks held by syz-executor.1/9696: #0: 0000000043753794 (&mm->mmap_sem){++++}, at: vm_mmap_pgoff+0x152/0x200 mm/util.c:355 #1: 000000007c61480a (sb_writers#29){.+.+}, at: sb_start_write_trylock include/linux/fs.h:1584 [inline] #1: 000000007c61480a (sb_writers#29){.+.+}, at: touch_atime+0x152/0x2a0 fs/inode.c:1731 stack backtrace: CPU: 1 PID: 9696 Comm: syz-executor.1 Not tainted 4.19.211-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1fc/0x2ef lib/dump_stack.c:118 print_circular_bug.constprop.0.cold+0x2d7/0x41e kernel/locking/lockdep.c:1222 check_prev_add kernel/locking/lockdep.c:1866 [inline] check_prevs_add kernel/locking/lockdep.c:1979 [inline] validate_chain kernel/locking/lockdep.c:2420 [inline] __lock_acquire+0x30c9/0x3ff0 kernel/locking/lockdep.c:3416 lock_acquire+0x170/0x3c0 kernel/locking/lockdep.c:3908 percpu_down_read_preempt_disable include/linux/percpu-rwsem.h:36 [inline] percpu_down_read include/linux/percpu-rwsem.h:59 [inline] __sb_start_write+0x6e/0x2a0 fs/super.c:1366 sb_start_intwrite include/linux/fs.h:1626 [inline] start_transaction+0xa37/0xf90 fs/btrfs/transaction.c:528 btrfs_dirty_inode+0xe3/0x210 fs/btrfs/inode.c:6165 btrfs_update_time+0x33b/0x3d0 fs/btrfs/inode.c:6207 update_time fs/inode.c:1675 [inline] touch_atime+0x23c/0x2a0 fs/inode.c:1746 file_accessed include/linux/fs.h:2123 [inline] btrfs_file_mmap+0x11b/0x160 fs/btrfs/file.c:2274 call_mmap include/linux/fs.h:1826 [inline] mmap_region+0xc94/0x16b0 mm/mmap.c:1757 do_mmap+0x8e8/0x1080 mm/mmap.c:1530 do_mmap_pgoff include/linux/mm.h:2329 [inline] vm_mmap_pgoff+0x197/0x200 mm/util.c:357 ksys_mmap_pgoff+0x298/0x5a0 mm/mmap.c:1580 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x7ff8ab957fe9 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 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ff8aa2cd168 EFLAGS: 00000246 ORIG_RAX: 0000000000000009 RAX: ffffffffffffffda RBX: 00007ff8aba6af60 RCX: 00007ff8ab957fe9 RDX: 0000000000000002 RSI: 0000000000b36000 RDI: 0000000020000000 RBP: 00007ff8ab9b208d R08: 0000000000000004 R09: 0000000000000000 R10: 0000000000028011 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffd15680dbf R14: 00007ff8aa2cd300 R15: 0000000000022000 BTRFS info (device loop1): disk space caching is enabled BTRFS info (device loop1): has skinny extents BTRFS info (device loop1): disk space caching is enabled BTRFS info (device loop1): has skinny extents audit: type=1804 audit(1642203229.810:519): pid=9872 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=invalid_pcr cause=open_writers comm="syz-executor.0" name="/root/syzkaller-testdir197513914/syzkaller.WLP7Wr/2562/file0" dev="sda1" ino=13877 res=1 audit: type=1804 audit(1642203230.650:520): pid=9898 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=invalid_pcr cause=open_writers comm="syz-executor.0" name="/root/syzkaller-testdir197513914/syzkaller.WLP7Wr/2563/file0" dev="sda1" ino=14547 res=1 audit: type=1804 audit(1642203232.791:521): pid=9920 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=invalid_pcr cause=open_writers comm="syz-executor.0" name="/root/syzkaller-testdir197513914/syzkaller.WLP7Wr/2564/file0" dev="sda1" ino=14257 res=1