====================================================== WARNING: possible circular locking dependency detected 6.13.0-rc3-syzkaller-00062-gc061cf420ded #0 Not tainted ------------------------------------------------------ syz.5.2161/14239 is trying to acquire lock: ffff88807ca1ae80 (&sb->s_type->i_mutex_key#23){++++}-{4:4}, at: inode_lock include/linux/fs.h:818 [inline] ffff88807ca1ae80 (&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: ffff888143714ee8 (&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] __bread_slow fs/buffer.c:1264 [inline] __bread_gfp+0x189/0x340 fs/buffer.c:1488 sb_bread include/linux/buffer_head.h:346 [inline] fat12_ent_bread+0x141/0x410 fs/fat/fatent.c:77 fat_ent_read_block fs/fat/fatent.c:445 [inline] fat_alloc_clusters+0x58b/0xf80 fs/fat/fatent.c:493 fat_alloc_new_dir+0x107/0xc30 fs/fat/dir.c:1156 vfat_mkdir+0x151/0x350 fs/fat/namei_vfat.c:859 vfs_mkdir+0x580/0x860 fs/namei.c:4311 do_mkdirat+0x301/0x3a0 fs/namei.c:4334 __do_sys_mkdirat fs/namei.c:4349 [inline] __se_sys_mkdirat fs/namei.c:4347 [inline] __x64_sys_mkdirat+0x83/0xb0 fs/namei.c:4347 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->fat_lock){+.+.}-{4:4}: __mutex_lock_common kernel/locking/mutex.c:585 [inline] __mutex_lock+0x19b/0xa60 kernel/locking/mutex.c:735 lock_fat fs/fat/fatent.c:281 [inline] fat_alloc_clusters+0x1b9/0xf80 fs/fat/fatent.c:477 fat_add_cluster+0x79/0x100 fs/fat/inode.c:107 __fat_get_block fs/fat/inode.c:154 [inline] fat_get_block+0x38e/0xaf0 fs/fat/inode.c:189 __block_write_begin_int+0x4fe/0x16e0 fs/buffer.c:2116 block_write_begin+0x9a/0x1d0 fs/buffer.c:2226 cont_write_begin+0x61d/0x950 fs/buffer.c:2577 fat_write_begin+0x66/0x150 fs/fat/inode.c:228 cont_expand_zero fs/buffer.c:2504 [inline] cont_write_begin+0x351/0x950 fs/buffer.c:2567 fat_write_begin+0x66/0x150 fs/fat/inode.c:228 generic_cont_expand_simple+0x124/0x210 fs/buffer.c:2468 fat_cont_expand+0x66/0x230 fs/fat/file.c:223 fat_setattr+0xbaa/0xff0 fs/fat/file.c:513 notify_change+0x6a9/0x1230 fs/attr.c:552 do_truncate+0x15c/0x220 fs/open.c:65 do_ftruncate+0x5d9/0x720 fs/open.c:181 do_sys_ftruncate+0x61/0xb0 fs/open.c:196 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->fat_lock --> &q->q_usage_counter(io)#26 Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&q->q_usage_counter(io)#26); lock(&sbi->fat_lock); lock(&q->q_usage_counter(io)#26); lock(&sb->s_type->i_mutex_key#23); *** DEADLOCK *** 3 locks held by syz.5.2161/14239: #0: ffff888025446b60 (&lo->lo_mutex){+.+.}-{4:4}, at: loop_set_status+0x2a/0x700 drivers/block/loop.c:1251 #1: ffff888143714ee8 (&q->q_usage_counter(io)#26){++++}-{0:0}, at: loop_set_status+0x1d9/0x700 drivers/block/loop.c:1267 #2: ffff888143714f20 (&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: 14239 Comm: syz.5.2161 Not tainted 6.13.0-rc3-syzkaller-00062-gc061cf420ded #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: 0033:0x7f3e06985d29 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:00007f3e077fd038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f3e06b75fa0 RCX: 00007f3e06985d29 RDX: 0000000020000480 RSI: 0000000000004c02 RDI: 0000000000000004 RBP: 00007f3e06a01a20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f3e06b75fa0 R15: 00007ffe91830208