[syzbot] [btrfs?] possible deadlock in write_all_supers
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syzbot
Oct 23, 2025, 10:07:29 PM (21 hours ago) Oct 23
to c...@fb.com, dst...@suse.com, jo...@toxicpanda.com, linux...@vger.kernel.org, linux-...@vger.kernel.org, syzkall...@googlegroups.com
Hello,
syzbot found the following issue on:
HEAD commit: 93f3bab4310d Add linux-next specific files for 20251017
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=17f96b04580000
kernel config: https://syzkaller.appspot.com/x/.config?x=408308c229eef498
dashboard link: https://syzkaller.appspot.com/bug?extid=f568e0df818a4f9d0dbb
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/c955a9337646/disk-93f3bab4.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/843962ea5283/vmlinux-93f3bab4.xz
kernel image: https://storage.googleapis.com/syzbot-assets/42360a7c5734/bzImage-93f3bab4.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+f568e0...@syzkaller.appspotmail.com
BTRFS info (device loop3): enabling ssd optimizations
BTRFS info (device loop3): turning on async discard
BTRFS info (device loop3): enabling free space tree
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.3.3420/21516 is trying to acquire lock:
ffff88805a8954d8 (&fs_devs->device_list_mutex){+.+.}-{4:4}, at: write_all_supers+0x13fa/0x47d0 fs/btrfs/disk-io.c:4027
but task is already holding lock:
ffff8880585647c0 (&fs_info->tree_log_mutex){+.+.}-{4:4}, at: btrfs_sync_log+0x1dc7/0x29a0 fs/btrfs/tree-log.c:3552
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #5 (&fs_info->tree_log_mutex){+.+.}-{4:4}:
lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868
__mutex_lock_common kernel/locking/mutex.c:598 [inline]
__mutex_lock+0x187/0x1350 kernel/locking/mutex.c:760
btrfs_sync_log+0x1dc7/0x29a0 fs/btrfs/tree-log.c:3552
btrfs_sync_file+0xcf9/0x1160 fs/btrfs/file.c:1771
generic_write_sync include/linux/fs.h:3046 [inline]
btrfs_do_write_iter+0x689/0x820 fs/btrfs/file.c:1470
do_iter_readv_writev+0x623/0x8c0 fs/read_write.c:-1
vfs_writev+0x31a/0x960 fs/read_write.c:1057
do_pwritev fs/read_write.c:1153 [inline]
__do_sys_pwritev2 fs/read_write.c:1211 [inline]
__se_sys_pwritev2+0x179/0x290 fs/read_write.c:1202
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #4 (btrfs_trans_num_extwriters){++++}-{0:0}:
lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868
join_transaction+0x1a4/0xd70 fs/btrfs/transaction.c:321
start_transaction+0x6b6/0x1620 fs/btrfs/transaction.c:705
btrfs_dirty_inode+0x9f/0x190 fs/btrfs/inode.c:6282
inode_update_time fs/inode.c:2117 [inline]
touch_atime+0x2f9/0x6d0 fs/inode.c:2190
file_accessed include/linux/fs.h:2673 [inline]
filemap_read+0x1002/0x11a0 mm/filemap.c:2826
__kernel_read+0x4cf/0x960 fs/read_write.c:530
integrity_kernel_read+0x89/0xd0 security/integrity/iint.c:28
ima_calc_file_hash_tfm security/integrity/ima/ima_crypto.c:480 [inline]
ima_calc_file_shash security/integrity/ima/ima_crypto.c:511 [inline]
ima_calc_file_hash+0x85e/0x16f0 security/integrity/ima/ima_crypto.c:568
ima_collect_measurement+0x428/0x8f0 security/integrity/ima/ima_api.c:293
process_measurement+0x1121/0x1a40 security/integrity/ima/ima_main.c:405
ima_file_check+0xd7/0x120 security/integrity/ima/ima_main.c:656
security_file_post_open+0xbb/0x290 security/security.c:3199
do_open fs/namei.c:3977 [inline]
path_openat+0x2f26/0x3830 fs/namei.c:4134
do_filp_open+0x1fa/0x410 fs/namei.c:4161
do_sys_openat2+0x121/0x1c0 fs/open.c:1437
do_sys_open fs/open.c:1452 [inline]
__do_sys_openat fs/open.c:1468 [inline]
__se_sys_openat fs/open.c:1463 [inline]
__x64_sys_openat+0x138/0x170 fs/open.c:1463
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #3 (btrfs_trans_num_writers){++++}-{0:0}:
reacquire_held_locks+0x127/0x1d0 kernel/locking/lockdep.c:5385
__lock_release kernel/locking/lockdep.c:5574 [inline]
lock_release+0x1b4/0x3e0 kernel/locking/lockdep.c:5889
percpu_up_read include/linux/percpu-rwsem.h:112 [inline]
__sb_end_write include/linux/fs.h:1911 [inline]
sb_end_intwrite+0x26/0x1c0 include/linux/fs.h:2028
__btrfs_end_transaction+0x248/0x640 fs/btrfs/transaction.c:1076
btrfs_dirty_inode+0x14c/0x190 fs/btrfs/inode.c:6296
inode_update_time fs/inode.c:2117 [inline]
touch_atime+0x2f9/0x6d0 fs/inode.c:2190
file_accessed include/linux/fs.h:2673 [inline]
btrfs_file_mmap_prepare+0x176/0x1f0 fs/btrfs/file.c:2052
vfs_mmap_prepare include/linux/fs.h:2410 [inline]
call_mmap_prepare mm/vma.c:2593 [inline]
__mmap_region mm/vma.c:2671 [inline]
mmap_region+0xb38/0x1c70 mm/vma.c:2764
do_mmap+0xc45/0x10d0 mm/mmap.c:558
vm_mmap_pgoff+0x2a6/0x4d0 mm/util.c:581
ksys_mmap_pgoff+0x51f/0x760 mm/mmap.c:604
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #2 (&mm->mmap_lock){++++}-{4:4}:
lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868
down_read_killable+0x50/0x350 kernel/locking/rwsem.c:1560
mmap_read_lock_killable+0x1d/0x70 include/linux/mmap_lock.h:377
get_mmap_lock_carefully mm/mmap_lock.c:377 [inline]
lock_mm_and_find_vma+0x2a8/0x300 mm/mmap_lock.c:428
do_user_addr_fault+0x331/0x1380 arch/x86/mm/fault.c:1359
handle_page_fault arch/x86/mm/fault.c:1476 [inline]
exc_page_fault+0x82/0x100 arch/x86/mm/fault.c:1532
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618
user_access_begin arch/x86/include/asm/uaccess.h:-1 [inline]
filldir+0x29c/0x6c0 fs/readdir.c:290
dir_emit_dot include/linux/fs.h:3991 [inline]
dir_emit_dots include/linux/fs.h:4002 [inline]
offset_readdir+0x1e6/0x560 fs/libfs.c:569
iterate_dir+0x399/0x570 fs/readdir.c:108
__do_sys_getdents fs/readdir.c:326 [inline]
__se_sys_getdents+0xe4/0x250 fs/readdir.c:312
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #1 (&type->i_mutex_dir_key#5){++++}-{4:4}:
lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868
down_read+0x46/0x2e0 kernel/locking/rwsem.c:1537
inode_lock_shared include/linux/fs.h:995 [inline]
lookup_slow+0x46/0x70 fs/namei.c:1832
walk_component+0x2d2/0x400 fs/namei.c:2151
lookup_last fs/namei.c:2652 [inline]
path_lookupat+0x163/0x430 fs/namei.c:2676
filename_lookup+0x212/0x570 fs/namei.c:2705
kern_path+0x35/0x50 fs/namei.c:2863
is_same_device fs/btrfs/volumes.c:759 [inline]
device_list_add+0xe2a/0x22a0 fs/btrfs/volumes.c:894
btrfs_scan_one_device+0x3ee/0x650 fs/btrfs/volumes.c:1493
btrfs_get_tree_super fs/btrfs/super.c:1865 [inline]
btrfs_get_tree_subvol fs/btrfs/super.c:2088 [inline]
btrfs_get_tree+0x436/0x1810 fs/btrfs/super.c:2122
vfs_get_tree+0x92/0x2b0 fs/super.c:1751
fc_mount fs/namespace.c:1208 [inline]
do_new_mount_fc fs/namespace.c:3651 [inline]
do_new_mount+0x302/0xa10 fs/namespace.c:3727
do_mount fs/namespace.c:4050 [inline]
__do_sys_mount fs/namespace.c:4238 [inline]
__se_sys_mount+0x313/0x410 fs/namespace.c:4215
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #0 (&fs_devs->device_list_mutex){+.+.}-{4:4}:
check_prev_add kernel/locking/lockdep.c:3165 [inline]
check_prevs_add kernel/locking/lockdep.c:3284 [inline]
validate_chain+0xb9b/0x2140 kernel/locking/lockdep.c:3908
__lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5237
lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868
__mutex_lock_common kernel/locking/mutex.c:598 [inline]
__mutex_lock+0x187/0x1350 kernel/locking/mutex.c:760
write_all_supers+0x13fa/0x47d0 fs/btrfs/disk-io.c:4027
btrfs_sync_log+0x1e95/0x29a0 fs/btrfs/tree-log.c:3571
btrfs_sync_file+0xcf9/0x1160 fs/btrfs/file.c:1771
generic_write_sync include/linux/fs.h:3046 [inline]
btrfs_do_write_iter+0x689/0x820 fs/btrfs/file.c:1470
aio_write+0x535/0x7a0 fs/aio.c:1634
__io_submit_one fs/aio.c:-1 [inline]
io_submit_one+0x78b/0x1310 fs/aio.c:2053
__do_sys_io_submit fs/aio.c:2112 [inline]
__se_sys_io_submit+0x185/0x2f0 fs/aio.c:2082
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
other info that might help us debug this:
Chain exists of:
&fs_devs->device_list_mutex --> btrfs_trans_num_extwriters --> &fs_info->tree_log_mutex
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&fs_info->tree_log_mutex);
lock(btrfs_trans_num_extwriters);
lock(&fs_info->tree_log_mutex);
lock(&fs_devs->device_list_mutex);
*** DEADLOCK ***
4 locks held by syz.3.3420/21516:
#0: ffff8880491ea610 (sb_internal#5){.+.+}-{0:0}, at: btrfs_sync_file+0xbf5/0x1160 fs/btrfs/file.c:1726
#1: ffff888058566538 (btrfs_trans_num_writers){++++}-{0:0}, at: join_transaction+0x41b/0xd70 fs/btrfs/transaction.c:296
#2: ffff888058566560 (btrfs_trans_num_extwriters){++++}-{0:0}, at: join_transaction+0x41b/0xd70 fs/btrfs/transaction.c:296
#3: ffff8880585647c0 (&fs_info->tree_log_mutex){+.+.}-{4:4}, at: btrfs_sync_log+0x1dc7/0x29a0 fs/btrfs/tree-log.c:3552
stack backtrace:
CPU: 1 UID: 0 PID: 21516 Comm: syz.3.3420 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Call Trace:
<TASK>
dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
print_circular_bug+0x2ee/0x310 kernel/locking/lockdep.c:2043
check_noncircular+0x134/0x160 kernel/locking/lockdep.c:2175
check_prev_add kernel/locking/lockdep.c:3165 [inline]
check_prevs_add kernel/locking/lockdep.c:3284 [inline]
validate_chain+0xb9b/0x2140 kernel/locking/lockdep.c:3908
__lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5237
lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868
__mutex_lock_common kernel/locking/mutex.c:598 [inline]
__mutex_lock+0x187/0x1350 kernel/locking/mutex.c:760
write_all_supers+0x13fa/0x47d0 fs/btrfs/disk-io.c:4027
btrfs_sync_log+0x1e95/0x29a0 fs/btrfs/tree-log.c:3571
btrfs_sync_file+0xcf9/0x1160 fs/btrfs/file.c:1771
generic_write_sync include/linux/fs.h:3046 [inline]
btrfs_do_write_iter+0x689/0x820 fs/btrfs/file.c:1470
aio_write+0x535/0x7a0 fs/aio.c:1634
__io_submit_one fs/aio.c:-1 [inline]
io_submit_one+0x78b/0x1310 fs/aio.c:2053
__do_sys_io_submit fs/aio.c:2112 [inline]
__se_sys_io_submit+0x185/0x2f0 fs/aio.c:2082
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe47278efc9
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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fe4736ad038 EFLAGS: 00000246 ORIG_RAX: 00000000000000d1
RAX: ffffffffffffffda RBX: 00007fe4729e5fa0 RCX: 00007fe47278efc9
RDX: 0000200000000540 RSI: 000000000000003b RDI: 00007fe473684000
RBP: 00007fe472811f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fe4729e6038 R14: 00007fe4729e5fa0 R15: 00007fff3a4e1998
</TASK>
BTRFS info (device loop3): last unmount of filesystem ed167579-eb65-4e76-9a50-61ac97e9b59d
---
This report is generated by a bot. It may contain errors.
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If you want to overwrite report's subsystems, reply with:
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If the report is a duplicate of another one, reply with:
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If you want to undo deduplication, reply with:
#syz undup
syzbot found the following issue on:
HEAD commit: 93f3bab4310d Add linux-next specific files for 20251017
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=17f96b04580000
kernel config: https://syzkaller.appspot.com/x/.config?x=408308c229eef498
dashboard link: https://syzkaller.appspot.com/bug?extid=f568e0df818a4f9d0dbb
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/c955a9337646/disk-93f3bab4.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/843962ea5283/vmlinux-93f3bab4.xz
kernel image: https://storage.googleapis.com/syzbot-assets/42360a7c5734/bzImage-93f3bab4.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+f568e0...@syzkaller.appspotmail.com
BTRFS info (device loop3): enabling ssd optimizations
BTRFS info (device loop3): turning on async discard
BTRFS info (device loop3): enabling free space tree
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.3.3420/21516 is trying to acquire lock:
ffff88805a8954d8 (&fs_devs->device_list_mutex){+.+.}-{4:4}, at: write_all_supers+0x13fa/0x47d0 fs/btrfs/disk-io.c:4027
but task is already holding lock:
ffff8880585647c0 (&fs_info->tree_log_mutex){+.+.}-{4:4}, at: btrfs_sync_log+0x1dc7/0x29a0 fs/btrfs/tree-log.c:3552
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #5 (&fs_info->tree_log_mutex){+.+.}-{4:4}:
lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868
__mutex_lock_common kernel/locking/mutex.c:598 [inline]
__mutex_lock+0x187/0x1350 kernel/locking/mutex.c:760
btrfs_sync_log+0x1dc7/0x29a0 fs/btrfs/tree-log.c:3552
btrfs_sync_file+0xcf9/0x1160 fs/btrfs/file.c:1771
generic_write_sync include/linux/fs.h:3046 [inline]
btrfs_do_write_iter+0x689/0x820 fs/btrfs/file.c:1470
do_iter_readv_writev+0x623/0x8c0 fs/read_write.c:-1
vfs_writev+0x31a/0x960 fs/read_write.c:1057
do_pwritev fs/read_write.c:1153 [inline]
__do_sys_pwritev2 fs/read_write.c:1211 [inline]
__se_sys_pwritev2+0x179/0x290 fs/read_write.c:1202
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #4 (btrfs_trans_num_extwriters){++++}-{0:0}:
lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868
join_transaction+0x1a4/0xd70 fs/btrfs/transaction.c:321
start_transaction+0x6b6/0x1620 fs/btrfs/transaction.c:705
btrfs_dirty_inode+0x9f/0x190 fs/btrfs/inode.c:6282
inode_update_time fs/inode.c:2117 [inline]
touch_atime+0x2f9/0x6d0 fs/inode.c:2190
file_accessed include/linux/fs.h:2673 [inline]
filemap_read+0x1002/0x11a0 mm/filemap.c:2826
__kernel_read+0x4cf/0x960 fs/read_write.c:530
integrity_kernel_read+0x89/0xd0 security/integrity/iint.c:28
ima_calc_file_hash_tfm security/integrity/ima/ima_crypto.c:480 [inline]
ima_calc_file_shash security/integrity/ima/ima_crypto.c:511 [inline]
ima_calc_file_hash+0x85e/0x16f0 security/integrity/ima/ima_crypto.c:568
ima_collect_measurement+0x428/0x8f0 security/integrity/ima/ima_api.c:293
process_measurement+0x1121/0x1a40 security/integrity/ima/ima_main.c:405
ima_file_check+0xd7/0x120 security/integrity/ima/ima_main.c:656
security_file_post_open+0xbb/0x290 security/security.c:3199
do_open fs/namei.c:3977 [inline]
path_openat+0x2f26/0x3830 fs/namei.c:4134
do_filp_open+0x1fa/0x410 fs/namei.c:4161
do_sys_openat2+0x121/0x1c0 fs/open.c:1437
do_sys_open fs/open.c:1452 [inline]
__do_sys_openat fs/open.c:1468 [inline]
__se_sys_openat fs/open.c:1463 [inline]
__x64_sys_openat+0x138/0x170 fs/open.c:1463
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #3 (btrfs_trans_num_writers){++++}-{0:0}:
reacquire_held_locks+0x127/0x1d0 kernel/locking/lockdep.c:5385
__lock_release kernel/locking/lockdep.c:5574 [inline]
lock_release+0x1b4/0x3e0 kernel/locking/lockdep.c:5889
percpu_up_read include/linux/percpu-rwsem.h:112 [inline]
__sb_end_write include/linux/fs.h:1911 [inline]
sb_end_intwrite+0x26/0x1c0 include/linux/fs.h:2028
__btrfs_end_transaction+0x248/0x640 fs/btrfs/transaction.c:1076
btrfs_dirty_inode+0x14c/0x190 fs/btrfs/inode.c:6296
inode_update_time fs/inode.c:2117 [inline]
touch_atime+0x2f9/0x6d0 fs/inode.c:2190
file_accessed include/linux/fs.h:2673 [inline]
btrfs_file_mmap_prepare+0x176/0x1f0 fs/btrfs/file.c:2052
vfs_mmap_prepare include/linux/fs.h:2410 [inline]
call_mmap_prepare mm/vma.c:2593 [inline]
__mmap_region mm/vma.c:2671 [inline]
mmap_region+0xb38/0x1c70 mm/vma.c:2764
do_mmap+0xc45/0x10d0 mm/mmap.c:558
vm_mmap_pgoff+0x2a6/0x4d0 mm/util.c:581
ksys_mmap_pgoff+0x51f/0x760 mm/mmap.c:604
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #2 (&mm->mmap_lock){++++}-{4:4}:
lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868
down_read_killable+0x50/0x350 kernel/locking/rwsem.c:1560
mmap_read_lock_killable+0x1d/0x70 include/linux/mmap_lock.h:377
get_mmap_lock_carefully mm/mmap_lock.c:377 [inline]
lock_mm_and_find_vma+0x2a8/0x300 mm/mmap_lock.c:428
do_user_addr_fault+0x331/0x1380 arch/x86/mm/fault.c:1359
handle_page_fault arch/x86/mm/fault.c:1476 [inline]
exc_page_fault+0x82/0x100 arch/x86/mm/fault.c:1532
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618
user_access_begin arch/x86/include/asm/uaccess.h:-1 [inline]
filldir+0x29c/0x6c0 fs/readdir.c:290
dir_emit_dot include/linux/fs.h:3991 [inline]
dir_emit_dots include/linux/fs.h:4002 [inline]
offset_readdir+0x1e6/0x560 fs/libfs.c:569
iterate_dir+0x399/0x570 fs/readdir.c:108
__do_sys_getdents fs/readdir.c:326 [inline]
__se_sys_getdents+0xe4/0x250 fs/readdir.c:312
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #1 (&type->i_mutex_dir_key#5){++++}-{4:4}:
lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868
down_read+0x46/0x2e0 kernel/locking/rwsem.c:1537
inode_lock_shared include/linux/fs.h:995 [inline]
lookup_slow+0x46/0x70 fs/namei.c:1832
walk_component+0x2d2/0x400 fs/namei.c:2151
lookup_last fs/namei.c:2652 [inline]
path_lookupat+0x163/0x430 fs/namei.c:2676
filename_lookup+0x212/0x570 fs/namei.c:2705
kern_path+0x35/0x50 fs/namei.c:2863
is_same_device fs/btrfs/volumes.c:759 [inline]
device_list_add+0xe2a/0x22a0 fs/btrfs/volumes.c:894
btrfs_scan_one_device+0x3ee/0x650 fs/btrfs/volumes.c:1493
btrfs_get_tree_super fs/btrfs/super.c:1865 [inline]
btrfs_get_tree_subvol fs/btrfs/super.c:2088 [inline]
btrfs_get_tree+0x436/0x1810 fs/btrfs/super.c:2122
vfs_get_tree+0x92/0x2b0 fs/super.c:1751
fc_mount fs/namespace.c:1208 [inline]
do_new_mount_fc fs/namespace.c:3651 [inline]
do_new_mount+0x302/0xa10 fs/namespace.c:3727
do_mount fs/namespace.c:4050 [inline]
__do_sys_mount fs/namespace.c:4238 [inline]
__se_sys_mount+0x313/0x410 fs/namespace.c:4215
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #0 (&fs_devs->device_list_mutex){+.+.}-{4:4}:
check_prev_add kernel/locking/lockdep.c:3165 [inline]
check_prevs_add kernel/locking/lockdep.c:3284 [inline]
validate_chain+0xb9b/0x2140 kernel/locking/lockdep.c:3908
__lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5237
lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868
__mutex_lock_common kernel/locking/mutex.c:598 [inline]
__mutex_lock+0x187/0x1350 kernel/locking/mutex.c:760
write_all_supers+0x13fa/0x47d0 fs/btrfs/disk-io.c:4027
btrfs_sync_log+0x1e95/0x29a0 fs/btrfs/tree-log.c:3571
btrfs_sync_file+0xcf9/0x1160 fs/btrfs/file.c:1771
generic_write_sync include/linux/fs.h:3046 [inline]
btrfs_do_write_iter+0x689/0x820 fs/btrfs/file.c:1470
aio_write+0x535/0x7a0 fs/aio.c:1634
__io_submit_one fs/aio.c:-1 [inline]
io_submit_one+0x78b/0x1310 fs/aio.c:2053
__do_sys_io_submit fs/aio.c:2112 [inline]
__se_sys_io_submit+0x185/0x2f0 fs/aio.c:2082
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
other info that might help us debug this:
Chain exists of:
&fs_devs->device_list_mutex --> btrfs_trans_num_extwriters --> &fs_info->tree_log_mutex
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&fs_info->tree_log_mutex);
lock(btrfs_trans_num_extwriters);
lock(&fs_info->tree_log_mutex);
lock(&fs_devs->device_list_mutex);
*** DEADLOCK ***
4 locks held by syz.3.3420/21516:
#0: ffff8880491ea610 (sb_internal#5){.+.+}-{0:0}, at: btrfs_sync_file+0xbf5/0x1160 fs/btrfs/file.c:1726
#1: ffff888058566538 (btrfs_trans_num_writers){++++}-{0:0}, at: join_transaction+0x41b/0xd70 fs/btrfs/transaction.c:296
#2: ffff888058566560 (btrfs_trans_num_extwriters){++++}-{0:0}, at: join_transaction+0x41b/0xd70 fs/btrfs/transaction.c:296
#3: ffff8880585647c0 (&fs_info->tree_log_mutex){+.+.}-{4:4}, at: btrfs_sync_log+0x1dc7/0x29a0 fs/btrfs/tree-log.c:3552
stack backtrace:
CPU: 1 UID: 0 PID: 21516 Comm: syz.3.3420 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Call Trace:
<TASK>
dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
print_circular_bug+0x2ee/0x310 kernel/locking/lockdep.c:2043
check_noncircular+0x134/0x160 kernel/locking/lockdep.c:2175
check_prev_add kernel/locking/lockdep.c:3165 [inline]
check_prevs_add kernel/locking/lockdep.c:3284 [inline]
validate_chain+0xb9b/0x2140 kernel/locking/lockdep.c:3908
__lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5237
lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868
__mutex_lock_common kernel/locking/mutex.c:598 [inline]
__mutex_lock+0x187/0x1350 kernel/locking/mutex.c:760
write_all_supers+0x13fa/0x47d0 fs/btrfs/disk-io.c:4027
btrfs_sync_log+0x1e95/0x29a0 fs/btrfs/tree-log.c:3571
btrfs_sync_file+0xcf9/0x1160 fs/btrfs/file.c:1771
generic_write_sync include/linux/fs.h:3046 [inline]
btrfs_do_write_iter+0x689/0x820 fs/btrfs/file.c:1470
aio_write+0x535/0x7a0 fs/aio.c:1634
__io_submit_one fs/aio.c:-1 [inline]
io_submit_one+0x78b/0x1310 fs/aio.c:2053
__do_sys_io_submit fs/aio.c:2112 [inline]
__se_sys_io_submit+0x185/0x2f0 fs/aio.c:2082
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe47278efc9
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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fe4736ad038 EFLAGS: 00000246 ORIG_RAX: 00000000000000d1
RAX: ffffffffffffffda RBX: 00007fe4729e5fa0 RCX: 00007fe47278efc9
RDX: 0000200000000540 RSI: 000000000000003b RDI: 00007fe473684000
RBP: 00007fe472811f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fe4729e6038 R14: 00007fe4729e5fa0 R15: 00007fff3a4e1998
</TASK>
BTRFS info (device loop3): last unmount of filesystem ed167579-eb65-4e76-9a50-61ac97e9b59d
---
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