loop1: detected capacity change from 0 to 8192 ====================================================== WARNING: possible circular locking dependency detected 6.13.0-rc2-syzkaller-00292-ga446e965a188 #0 Not tainted ------------------------------------------------------ syz.1.1315/11481 is trying to acquire lock: ffff88804b86cde8 (&sb->s_type->i_mutex_key#38){++++}-{4:4}, at: inode_lock include/linux/fs.h:818 [inline] ffff88804b86cde8 (&sb->s_type->i_mutex_key#38){++++}-{4:4}, at: __generic_file_fsync+0xb0/0x1f0 fs/libfs.c:1536 but task is already holding lock: ffff8881437c58b0 (&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:3090 __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 vfat_add_entry+0x298d/0x2fe0 fs/fat/namei_vfat.c:677 vfat_create+0x15f/0x2c0 fs/fat/namei_vfat.c:771 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 vfat_lookup+0x123/0x5b0 fs/fat/namei_vfat.c:710 __lookup_slow+0x252/0x460 fs/namei.c:1791 lookup_slow fs/namei.c:1808 [inline] walk_component+0x350/0x5b0 fs/namei.c:2112 lookup_last fs/namei.c:2610 [inline] path_lookupat+0x17f/0x770 fs/namei.c:2634 filename_lookup+0x221/0x5f0 fs/namei.c:2663 filename_removexattr fs/xattr.c:1047 [inline] path_removexattrat+0x1f1/0x5d0 fs/xattr.c:1088 __do_sys_removexattr fs/xattr.c:1100 [inline] __se_sys_removexattr fs/xattr.c:1097 [inline] __x64_sys_removexattr+0x5b/0x80 fs/xattr.c:1097 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#38){++++}-{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#38 --> &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#38); *** DEADLOCK *** 3 locks held by syz.1.1315/11481: #0: ffff888025452360 (&lo->lo_mutex){+.+.}-{4:4}, at: loop_set_status+0x2a/0x700 drivers/block/loop.c:1251 #1: ffff8881437c58b0 (&q->q_usage_counter(io)#26){++++}-{0:0}, at: loop_set_status+0x1d9/0x700 drivers/block/loop.c:1267 #2: ffff8881437c58e8 (&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: 11481 Comm: syz.1.1315 Not tainted 6.13.0-rc2-syzkaller-00292-ga446e965a188 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/25/2024 Call Trace: __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: 0033:0x7f5146585d19 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:00007f51473ed038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f5146775fa0 RCX: 00007f5146585d19 RDX: 0000000020000480 RSI: 0000000000004c02 RDI: 0000000000000004 RBP: 00007f5146601a20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f5146775fa0 R15: 00007ffc4bfa4758