====================================================== WARNING: possible circular locking dependency detected 5.15.179-syzkaller #0 Not tainted ------------------------------------------------------ syz.0.40/4305 is trying to acquire lock: ffff0000d171d4e0 (&fs_devs->device_list_mutex){+.+.}-{3:3}, at: btrfs_run_dev_stats+0xe4/0xe24 fs/btrfs/volumes.c:7985 but task is already holding lock: ffff0000eccf0720 (&fs_info->tree_log_mutex){+.+.}-{3:3}, at: btrfs_commit_transaction+0xe34/0x30f0 fs/btrfs/transaction.c:2369 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #5 (&fs_info->tree_log_mutex){+.+.}-{3:3}: __mutex_lock_common+0x194/0x2154 kernel/locking/mutex.c:596 __mutex_lock kernel/locking/mutex.c:729 [inline] mutex_lock_nested+0xa4/0xf8 kernel/locking/mutex.c:743 btrfs_commit_transaction+0xe34/0x30f0 fs/btrfs/transaction.c:2369 btrfs_sync_fs+0x678/0xc94 fs/btrfs/super.c:1454 sync_filesystem+0x1a0/0x218 fs/sync.c:66 btrfs_remount+0x198/0x130c fs/btrfs/super.c:1928 legacy_reconfigure+0xfc/0x114 fs/fs_context.c:634 reconfigure_super+0x1d0/0x6ec fs/super.c:938 do_remount fs/namespace.c:2668 [inline] path_mount+0xbec/0x101c fs/namespace.c:3334 do_mount fs/namespace.c:3355 [inline] __do_sys_mount fs/namespace.c:3563 [inline] __se_sys_mount fs/namespace.c:3540 [inline] __arm64_sys_mount+0x510/0x5e0 fs/namespace.c:3540 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181 el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608 el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584 -> #4 (&fs_info->reloc_mutex){+.+.}-{3:3}: __mutex_lock_common+0x194/0x2154 kernel/locking/mutex.c:596 __mutex_lock kernel/locking/mutex.c:729 [inline] mutex_lock_nested+0xa4/0xf8 kernel/locking/mutex.c:743 btrfs_record_root_in_trans fs/btrfs/transaction.c:513 [inline] start_transaction+0x450/0x1480 fs/btrfs/transaction.c:750 btrfs_start_transaction+0x34/0x44 fs/btrfs/transaction.c:779 btrfs_create+0x134/0x56c fs/btrfs/inode.c:6900 lookup_open fs/namei.c:3462 [inline] open_last_lookups fs/namei.c:3532 [inline] path_openat+0xf18/0x26cc fs/namei.c:3739 do_filp_open+0x1a8/0x3b4 fs/namei.c:3769 do_sys_openat2+0x128/0x3e0 fs/open.c:1253 do_sys_open fs/open.c:1269 [inline] __do_sys_openat fs/open.c:1285 [inline] __se_sys_openat fs/open.c:1280 [inline] __arm64_sys_openat+0x1f0/0x240 fs/open.c:1280 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181 el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608 el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584 -> #3 (sb_internal#3){.+.+}-{0:0}: percpu_down_read include/linux/percpu-rwsem.h:51 [inline] __sb_start_write include/linux/fs.h:1811 [inline] sb_start_intwrite include/linux/fs.h:1928 [inline] start_transaction+0x644/0x1480 fs/btrfs/transaction.c:680 btrfs_join_transaction+0x30/0x40 fs/btrfs/transaction.c:793 btrfs_dirty_inode+0xb4/0x1c0 fs/btrfs/inode.c:6436 btrfs_update_time+0x248/0x270 fs/btrfs/inode.c:6478 inode_update_time fs/inode.c:1893 [inline] touch_atime+0x434/0xa4c fs/inode.c:1966 file_accessed include/linux/fs.h:2521 [inline] btrfs_file_mmap+0xb0/0x11c fs/btrfs/file.c:2449 call_mmap include/linux/fs.h:2177 [inline] mmap_file+0x6c/0xc8 mm/util.c:1092 __mmap_region mm/mmap.c:1784 [inline] mmap_region+0xb24/0x1408 mm/mmap.c:2921 do_mmap+0x698/0xdc4 mm/mmap.c:1574 vm_mmap_pgoff+0x1a4/0x2b4 mm/util.c:551 ksys_mmap_pgoff+0x458/0x668 mm/mmap.c:1623 __do_sys_mmap arch/arm64/kernel/sys.c:28 [inline] __se_sys_mmap arch/arm64/kernel/sys.c:21 [inline] __arm64_sys_mmap+0xf8/0x110 arch/arm64/kernel/sys.c:21 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181 el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608 el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584 -> #2 (&mm->mmap_lock){++++}-{3:3}: __might_fault+0xc8/0x128 mm/memory.c:5357 filldir64+0x2bc/0x9e4 fs/readdir.c:335 dir_emit_dot include/linux/fs.h:3715 [inline] dir_emit_dots include/linux/fs.h:3726 [inline] dcache_readdir+0x134/0x678 fs/libfs.c:196 iterate_dir+0x1f4/0x4ec __do_sys_getdents64 fs/readdir.c:369 [inline] __se_sys_getdents64 fs/readdir.c:354 [inline] __arm64_sys_getdents64+0x1c4/0x4c4 fs/readdir.c:354 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181 el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608 el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584 -> #1 (&type->i_mutex_dir_key#5){++++}-{3:3}: down_read+0xc0/0x398 kernel/locking/rwsem.c:1498 inode_lock_shared include/linux/fs.h:797 [inline] lookup_slow+0x50/0x84 fs/namei.c:1679 walk_component+0x394/0x4cc fs/namei.c:1976 lookup_last fs/namei.c:2431 [inline] path_lookupat+0x13c/0x3d0 fs/namei.c:2455 filename_lookup+0x1c4/0x4c8 fs/namei.c:2484 kern_path+0x4c/0x194 fs/namei.c:2582 lookup_bdev+0xc0/0x25c block/bdev.c:982 device_matched fs/btrfs/volumes.c:568 [inline] btrfs_free_stale_devices+0x658/0x9ec fs/btrfs/volumes.c:608 btrfs_forget_devices+0x5c/0x98 fs/btrfs/volumes.c:1431 btrfs_control_ioctl+0x12c/0x248 fs/btrfs/super.c:2451 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:874 [inline] __se_sys_ioctl fs/ioctl.c:860 [inline] __arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:860 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181 el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608 el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584 -> #0 (&fs_devs->device_list_mutex){+.+.}-{3:3}: check_prev_add kernel/locking/lockdep.c:3053 [inline] check_prevs_add kernel/locking/lockdep.c:3172 [inline] validate_chain kernel/locking/lockdep.c:3788 [inline] __lock_acquire+0x32d4/0x7638 kernel/locking/lockdep.c:5012 lock_acquire+0x240/0x77c kernel/locking/lockdep.c:5623 __mutex_lock_common+0x194/0x2154 kernel/locking/mutex.c:596 __mutex_lock kernel/locking/mutex.c:729 [inline] mutex_lock_nested+0xa4/0xf8 kernel/locking/mutex.c:743 btrfs_run_dev_stats+0xe4/0xe24 fs/btrfs/volumes.c:7985 commit_cowonly_roots+0x17c/0x808 fs/btrfs/transaction.c:1292 btrfs_commit_transaction+0xef4/0x30f0 fs/btrfs/transaction.c:2394 btrfs_sync_fs+0x678/0xc94 fs/btrfs/super.c:1454 sync_filesystem+0x1a0/0x218 fs/sync.c:66 btrfs_remount+0x198/0x130c fs/btrfs/super.c:1928 legacy_reconfigure+0xfc/0x114 fs/fs_context.c:634 reconfigure_super+0x1d0/0x6ec fs/super.c:938 do_remount fs/namespace.c:2668 [inline] path_mount+0xbec/0x101c fs/namespace.c:3334 do_mount fs/namespace.c:3355 [inline] __do_sys_mount fs/namespace.c:3563 [inline] __se_sys_mount fs/namespace.c:3540 [inline] __arm64_sys_mount+0x510/0x5e0 fs/namespace.c:3540 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181 el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608 el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584 other info that might help us debug this: Chain exists of: &fs_devs->device_list_mutex --> &fs_info->reloc_mutex --> &fs_info->tree_log_mutex Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&fs_info->tree_log_mutex); lock(&fs_info->reloc_mutex); lock(&fs_info->tree_log_mutex); lock(&fs_devs->device_list_mutex); *** DEADLOCK *** 3 locks held by syz.0.40/4305: #0: ffff0000dd0dc0e0 (&type->s_umount_key#60){+.+.}-{3:3}, at: do_remount fs/namespace.c:2665 [inline] #0: ffff0000dd0dc0e0 (&type->s_umount_key#60){+.+.}-{3:3}, at: path_mount+0xbbc/0x101c fs/namespace.c:3334 #1: ffff0000eccf0c90 (&fs_info->reloc_mutex){+.+.}-{3:3}, at: btrfs_commit_transaction+0xd9c/0x30f0 fs/btrfs/transaction.c:2319 #2: ffff0000eccf0720 (&fs_info->tree_log_mutex){+.+.}-{3:3}, at: btrfs_commit_transaction+0xe34/0x30f0 fs/btrfs/transaction.c:2369 stack backtrace: CPU: 0 PID: 4305 Comm: syz.0.40 Not tainted 5.15.179-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Call trace: dump_backtrace+0x0/0x530 arch/arm64/kernel/stacktrace.c:152 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:216 __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x108/0x170 lib/dump_stack.c:106 dump_stack+0x1c/0x58 lib/dump_stack.c:113 print_circular_bug+0x150/0x1b8 kernel/locking/lockdep.c:2011 check_noncircular+0x2cc/0x378 kernel/locking/lockdep.c:2133 check_prev_add kernel/locking/lockdep.c:3053 [inline] check_prevs_add kernel/locking/lockdep.c:3172 [inline] validate_chain kernel/locking/lockdep.c:3788 [inline] __lock_acquire+0x32d4/0x7638 kernel/locking/lockdep.c:5012 lock_acquire+0x240/0x77c kernel/locking/lockdep.c:5623 __mutex_lock_common+0x194/0x2154 kernel/locking/mutex.c:596 __mutex_lock kernel/locking/mutex.c:729 [inline] mutex_lock_nested+0xa4/0xf8 kernel/locking/mutex.c:743 btrfs_run_dev_stats+0xe4/0xe24 fs/btrfs/volumes.c:7985 commit_cowonly_roots+0x17c/0x808 fs/btrfs/transaction.c:1292 btrfs_commit_transaction+0xef4/0x30f0 fs/btrfs/transaction.c:2394 btrfs_sync_fs+0x678/0xc94 fs/btrfs/super.c:1454 sync_filesystem+0x1a0/0x218 fs/sync.c:66 btrfs_remount+0x198/0x130c fs/btrfs/super.c:1928 legacy_reconfigure+0xfc/0x114 fs/fs_context.c:634 reconfigure_super+0x1d0/0x6ec fs/super.c:938 do_remount fs/namespace.c:2668 [inline] path_mount+0xbec/0x101c fs/namespace.c:3334 do_mount fs/namespace.c:3355 [inline] __do_sys_mount fs/namespace.c:3563 [inline] __se_sys_mount fs/namespace.c:3540 [inline] __arm64_sys_mount+0x510/0x5e0 fs/namespace.c:3540 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181 el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608 el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584