===================================== WARNING: bad unlock balance detected! 6.15.0-rc2-syzkaller-00042-g1a1d569a75f3-dirty #0 Not tainted ------------------------------------- syz.0.17/6157 is trying to release lock (&sbi->s_alloc_mutex) at: [] udf_free_blocks+0x25e/0x23b0 fs/udf/balloc.c:678 but there are no more locks to release! other info that might help us debug this: 3 locks held by syz.0.17/6157: #0: ffff88806ddbc420 (sb_writers#12){.+.+}-{0:0}, at: direct_splice_actor+0x49/0x220 fs/splice.c:1157 #1: ffff88805f0795c0 (&sb->s_type->i_mutex_key#21){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:867 [inline] #1: ffff88805f0795c0 (&sb->s_type->i_mutex_key#21){+.+.}-{4:4}, at: udf_file_write_iter+0x6d/0x6c0 fs/udf/file.c:95 #2: ffff88805f0793f0 (&ei->i_data_sem#2){++++}-{4:4}, at: udf_map_block+0x3b9/0x53f0 fs/udf/inode.c:439 stack backtrace: CPU: 1 UID: 0 PID: 6157 Comm: syz.0.17 Not tainted 6.15.0-rc2-syzkaller-00042-g1a1d569a75f3-dirty #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 print_unlock_imbalance_bug+0x185/0x1a0 kernel/locking/lockdep.c:5296 __lock_release kernel/locking/lockdep.c:5535 [inline] lock_release+0x1ed/0x3e0 kernel/locking/lockdep.c:5887 __mutex_unlock_slowpath+0xee/0x800 kernel/locking/mutex.c:907 udf_free_blocks+0x25e/0x23b0 fs/udf/balloc.c:678 udf_merge_extents fs/udf/inode.c:1143 [inline] inode_getblk fs/udf/inode.c:914 [inline] udf_map_block+0x3061/0x53f0 fs/udf/inode.c:447 __udf_get_block+0x128/0x410 fs/udf/inode.c:461 __block_write_begin_int+0x693/0x1930 fs/buffer.c:2116 block_write_begin+0x8f/0x120 fs/buffer.c:2227 udf_write_begin+0xfc/0x250 fs/udf/inode.c:256 generic_perform_write+0x32b/0xa10 mm/filemap.c:4102 udf_file_write_iter+0x2e7/0x6c0 fs/udf/file.c:111 iter_file_splice_write+0xbe1/0x1530 fs/splice.c:738 do_splice_from fs/splice.c:935 [inline] direct_splice_actor+0x11d/0x220 fs/splice.c:1158 splice_direct_to_actor+0x597/0xc90 fs/splice.c:1102 do_splice_direct_actor fs/splice.c:1201 [inline] do_splice_direct+0x281/0x3d0 fs/splice.c:1227 do_sendfile+0x582/0x8c0 fs/read_write.c:1368 __do_sys_sendfile64 fs/read_write.c:1429 [inline] __se_sys_sendfile64+0x17e/0x1e0 fs/read_write.c:1415 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fedc3385d29 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:00007fedc41b4038 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 00007fedc3576080 RCX: 00007fedc3385d29 RDX: 0000000000000000 RSI: 0000000000000006 RDI: 0000000000000005 RBP: 00007fedc3401aa8 R08: 0000000000000000 R09: 0000000000000000 R10: 0001000000201005 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fedc3576080 R15: 00007ffc4f30ca78