loop8: detected capacity change from 0 to 8192
======================================================
WARNING: possible circular locking dependency detected
6.13.0-rc2-syzkaller-00130-g150b567e0d57 #0 Not tainted
------------------------------------------------------
syz.8.2317/15297 is trying to acquire lock:
ffff888077e6e0c0 (&sb->s_type->i_mutex_key#23){++++}-{4:4}, at: inode_lock include/linux/fs.h:818 [inline]
ffff888077e6e0c0 (&sb->s_type->i_mutex_key#23){++++}-{4:4}, at: __generic_file_fsync+0xb0/0x1f0 fs/libfs.c:1536
but task is already holding lock:
ffff88802593bb58 (&q->q_usage_counter(io)#26){++++}-{0:0}, at: loop_set_status+0x1d9/0x700 drivers/block/loop.c:1267
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #2 (&q->q_usage_counter(io)#26){++++}-{0:0}:
bio_queue_enter block/blk.h:75 [inline]
blk_mq_submit_bio+0x1fb6/0x24c0 block/blk-mq.c:3092
__submit_bio+0x384/0x540 block/blk-core.c:629
__submit_bio_noacct_mq block/blk-core.c:710 [inline]
submit_bio_noacct_nocheck+0x698/0xd70 block/blk-core.c:739
submit_bio_noacct+0x93a/0x1e20 block/blk-core.c:868
submit_bh fs/buffer.c:2819 [inline]
__sync_dirty_buffer+0x173/0x370 fs/buffer.c:2857
fat_add_entries+0x11d2/0x1530 fs/fat/dir.c:1372
msdos_add_entry+0x1f0/0x380 fs/fat/namei_msdos.c:250
msdos_create+0x34c/0x680 fs/fat/namei_msdos.c:289
lookup_open.isra.0+0x1177/0x14c0 fs/namei.c:3649
open_last_lookups fs/namei.c:3748 [inline]
path_openat+0x904/0x2d60 fs/namei.c:3984
do_filp_open+0x20c/0x470 fs/namei.c:4014
do_sys_openat2+0x17a/0x1e0 fs/open.c:1402
do_sys_open fs/open.c:1417 [inline]
__do_sys_openat fs/open.c:1433 [inline]
__se_sys_openat fs/open.c:1428 [inline]
__x64_sys_openat+0x175/0x210 fs/open.c:1428
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #1 (&sbi->s_lock#2){+.+.}-{4:4}:
__mutex_lock_common kernel/locking/mutex.c:585 [inline]
__mutex_lock+0x19b/0xa60 kernel/locking/mutex.c:735
__fat_readdir+0x1b7/0x1a90 fs/fat/dir.c:583
iterate_dir+0x532/0xb40 fs/readdir.c:108
__do_sys_getdents64 fs/readdir.c:403 [inline]
__se_sys_getdents64 fs/readdir.c:389 [inline]
__x64_sys_getdents64+0x148/0x2c0 fs/readdir.c:389
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #0 (&sb->s_type->i_mutex_key#23){++++}-{4:4}:
check_prev_add kernel/locking/lockdep.c:3161 [inline]
check_prevs_add kernel/locking/lockdep.c:3280 [inline]
validate_chain kernel/locking/lockdep.c:3904 [inline]
__lock_acquire+0x249e/0x3c40 kernel/locking/lockdep.c:5226
lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5849
down_write+0x93/0x200 kernel/locking/rwsem.c:1577
inode_lock include/linux/fs.h:818 [inline]
__generic_file_fsync+0xb0/0x1f0 fs/libfs.c:1536
fat_file_fsync+0x70/0x210 fs/fat/file.c:191
vfs_fsync_range fs/sync.c:187 [inline]
vfs_fsync+0x12d/0x1f0 fs/sync.c:201
__loop_update_dio+0x182/0x570 drivers/block/loop.c:204
loop_set_status+0x2a4/0x700 drivers/block/loop.c:1289
loop_set_status_old+0x163/0x1d0 drivers/block/loop.c:1388
lo_ioctl+0x65c/0x18b0 drivers/block/loop.c:1541
blkdev_ioctl+0x279/0x6d0 block/ioctl.c:693
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:906 [inline]
__se_sys_ioctl fs/ioctl.c:892 [inline]
__x64_sys_ioctl+0x193/0x200 fs/ioctl.c:892
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
other info that might help us debug this:
Chain exists of:
&sb->s_type->i_mutex_key#23 --> &sbi->s_lock#2 --> &q->q_usage_counter(io)#26
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&q->q_usage_counter(io)#26);
lock(&sbi->s_lock#2);
lock(&q->q_usage_counter(io)#26);
lock(&sb->s_type->i_mutex_key#23);
*** DEADLOCK ***
3 locks held by syz.8.2317/15297:
#0: ffff88802597eb60 (&lo->lo_mutex){+.+.}-{4:4}, at: loop_set_status+0x2a/0x700 drivers/block/loop.c:1251
#1: ffff88802593bb58 (&q->q_usage_counter(io)#26){++++}-{0:0}, at: loop_set_status+0x1d9/0x700 drivers/block/loop.c:1267
#2: ffff88802593bb90 (&q->q_usage_counter(queue)#10){+.+.}-{0:0}, at: loop_set_status+0x1d9/0x700 drivers/block/loop.c:1267
stack backtrace:
CPU: 0 UID: 0 PID: 15297 Comm: syz.8.2317 Not tainted 6.13.0-rc2-syzkaller-00130-g150b567e0d57 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/25/2024
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
print_circular_bug+0x419/0x5d0 kernel/locking/lockdep.c:2074
check_noncircular+0x31a/0x400 kernel/locking/lockdep.c:2206
check_prev_add kernel/locking/lockdep.c:3161 [inline]
check_prevs_add kernel/locking/lockdep.c:3280 [inline]
validate_chain kernel/locking/lockdep.c:3904 [inline]
__lock_acquire+0x249e/0x3c40 kernel/locking/lockdep.c:5226
lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5849
down_write+0x93/0x200 kernel/locking/rwsem.c:1577
inode_lock include/linux/fs.h:818 [inline]
__generic_file_fsync+0xb0/0x1f0 fs/libfs.c:1536
fat_file_fsync+0x70/0x210 fs/fat/file.c:191
vfs_fsync_range fs/sync.c:187 [inline]
vfs_fsync+0x12d/0x1f0 fs/sync.c:201
__loop_update_dio+0x182/0x570 drivers/block/loop.c:204
loop_set_status+0x2a4/0x700 drivers/block/loop.c:1289
loop_set_status_old+0x163/0x1d0 drivers/block/loop.c:1388
lo_ioctl+0x65c/0x18b0 drivers/block/loop.c:1541
blkdev_ioctl+0x279/0x6d0 block/ioctl.c:693
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:906 [inline]
__se_sys_ioctl fs/ioctl.c:892 [inline]
__x64_sys_ioctl+0x193/0x200 fs/ioctl.c:892
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f94d8185d19
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:00007f94d8f8d038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f94d8375fa0 RCX: 00007f94d8185d19
RDX: 0000000020000480 RSI: 0000000000004c02 RDI: 0000000000000004
RBP: 00007f94d8201a20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f94d8375fa0 R15: 00007ffeaa74fe98
</TASK>