======================================================
WARNING: possible circular locking dependency detected
6.1.0-rc5-syzkaller-00103-g81ac25651a62 #0 Not tainted
------------------------------------------------------
syz-executor921/3638 is trying to acquire lock:
ffff888078d624d8 (btrfs-root-00){.+.+}-{3:3}, at: __btrfs_tree_read_lock fs/btrfs/locking.c:134 [inline]
ffff888078d624d8 (btrfs-root-00){.+.+}-{3:3}, at: btrfs_tree_read_lock fs/btrfs/locking.c:140 [inline]
ffff888078d624d8 (btrfs-root-00){.+.+}-{3:3}, at: btrfs_read_lock_root_node+0x2b4/0x400 fs/btrfs/locking.c:279
but task is already holding lock:
ffff888027970cc0 (&fs_info->reloc_mutex){+.+.}-{3:3}, at: btrfs_commit_transaction+0x13e8/0x3760 fs/btrfs/transaction.c:2316
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #4 (&fs_info->reloc_mutex){+.+.}-{3:3}:
lock_acquire+0x182/0x3c0 kernel/locking/lockdep.c:5668
__mutex_lock_common+0x1bd/0x26e0 kernel/locking/mutex.c:603
__mutex_lock kernel/locking/mutex.c:747 [inline]
mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:799
btrfs_record_root_in_trans+0x153/0x180 fs/btrfs/transaction.c:484
start_transaction+0x3af/0x1180 fs/btrfs/transaction.c:721
btrfs_create_common+0x2c6/0x420 fs/btrfs/inode.c:6633
lookup_open fs/namei.c:3413 [inline]
open_last_lookups fs/namei.c:3481 [inline]
path_openat+0x12d0/0x2df0 fs/namei.c:3710
do_filp_open+0x264/0x4f0 fs/namei.c:3740
do_sys_openat2+0x124/0x4e0 fs/open.c:1310
do_sys_open fs/open.c:1326 [inline]
__do_sys_open fs/open.c:1334 [inline]
__se_sys_open fs/open.c:1330 [inline]
__x64_sys_open+0x221/0x270 fs/open.c:1330
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
-> #3 (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_create_common+0x2c6/0x420 fs/btrfs/inode.c:6633
lookup_open fs/namei.c:3413 [inline]
open_last_lookups fs/namei.c:3481 [inline]
path_openat+0x12d0/0x2df0 fs/namei.c:3710
do_filp_open+0x264/0x4f0 fs/namei.c:3740
do_sys_openat2+0x124/0x4e0 fs/open.c:1310
do_sys_open fs/open.c:1326 [inline]
__do_sys_open fs/open.c:1334 [inline]
__se_sys_open fs/open.c:1330 [inline]
__x64_sys_open+0x221/0x270 fs/open.c:1330
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_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+0xfe6/0x1e20 mm/mmap.c:2625
do_mmap+0x8d9/0xf30 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
-> #1 (&mm->mmap_lock#2){++++}-{3:3}:
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
-> #0 (btrfs-root-00){.+.+}-{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
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:1665 [inline]
btrfs_search_slot+0x495/0x2fe0 fs/btrfs/ctree.c:1985
btrfs_update_root+0xf0/0xc60 fs/btrfs/root-tree.c:132
commit_fs_roots+0x4d3/0x710 fs/btrfs/transaction.c:1441
btrfs_commit_transaction+0x147f/0x3760 fs/btrfs/transaction.c:2353
sync_filesystem+0x1bc/0x220 fs/sync.c:66
generic_shutdown_super+0x6b/0x310 fs/super.c:474
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
exit_task_work include/linux/task_work.h:38 [inline]
do_exit+0x664/0x2070 kernel/exit.c:820
do_group_exit+0x1fd/0x2b0 kernel/exit.c:950
__do_sys_exit_group kernel/exit.c:961 [inline]
__se_sys_exit_group kernel/exit.c:959 [inline]
__x64_sys_exit_group+0x3b/0x40 kernel/exit.c:959
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:
btrfs-root-00 --> btrfs_trans_num_extwriters --> &fs_info->reloc_mutex
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&fs_info->reloc_mutex);
lock(btrfs_trans_num_extwriters);
lock(&fs_info->reloc_mutex);
lock(btrfs-root-00);
*** DEADLOCK ***
5 locks held by syz-executor921/3638:
#0: ffff888027d580e0 (&type->s_umount_key#44){++++}-{3:3}, at: deactivate_super+0x96/0xd0 fs/super.c:362
#1: ffff8880279723f0 (btrfs_trans_completed){.+.+}-{0:0}, at: btrfs_commit_transaction+0x130f/0x3760 fs/btrfs/transaction.c:2295
#2: ffff8880279723c8 (btrfs_trans_super_committed){.+.+}-{0:0}, at: btrfs_commit_transaction+0x133e/0x3760 fs/btrfs/transaction.c:2296
#3: ffff8880279723a0 (btrfs_trans_unblocked){.+.+}-{0:0}, at: btrfs_commit_transaction+0x136d/0x3760 fs/btrfs/transaction.c:2297
#4: ffff888027970cc0 (&fs_info->reloc_mutex){+.+.}-{3:3}, at: btrfs_commit_transaction+0x13e8/0x3760 fs/btrfs/transaction.c:2316
stack backtrace:
CPU: 0 PID: 3638 Comm: syz-executor921 Not tainted 6.1.0-rc5-syzkaller-00103-g81ac25651a62 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
Call Trace:
<TASK>
__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
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:1665 [inline]
btrfs_search_slot+0x495/0x2fe0 fs/btrfs/ctree.c:1985
btrfs_update_root+0xf0/0xc60 fs/btrfs/root-tree.c:132
commit_fs_roots+0x4d3/0x710 fs/btrfs/transaction.c:1441
btrfs_commit_transaction+0x147f/0x3760 fs/btrfs/transaction.c:2353
sync_filesystem+0x1bc/0x220 fs/sync.c:66
generic_shutdown_super+0x6b/0x310 fs/super.c:474
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
exit_task_work include/linux/task_work.h:38 [inline]
do_exit+0x664/0x2070 kernel/exit.c:820
do_group_exit+0x1fd/0x2b0 kernel/exit.c:950
__do_sys_exit_group kernel/exit.c:961 [inline]
__se_sys_exit_group kernel/exit.c:959 [inline]
__x64_sys_exit_group+0x3b/0x40 kernel/exit.c:959
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: 0033:0x7f3312c7c869
Code: Unable to access opcode bytes at 0x7f3312c7c83f.
RSP: 002b:00007ffdbbcb5da8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7