============================================ WARNING: possible recursive locking detected syzkaller #0 Not tainted -------------------------------------------- syz.3.5432/25287 is trying to acquire lock: ffff8880564d3d28 (&sbi->s_alloc_mutex){+.+.}-{3:3}, at: udf_table_free_blocks fs/udf/balloc.c:392 [inline] ffff8880564d3d28 (&sbi->s_alloc_mutex){+.+.}-{3:3}, at: udf_free_blocks+0x9a6/0x17e0 fs/udf/balloc.c:694 but task is already holding lock: ffff8880564d3d28 (&sbi->s_alloc_mutex){+.+.}-{3:3}, at: udf_table_new_block fs/udf/balloc.c:598 [inline] ffff8880564d3d28 (&sbi->s_alloc_mutex){+.+.}-{3:3}, at: udf_new_block+0xe29/0x1a00 fs/udf/balloc.c:742 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&sbi->s_alloc_mutex); lock(&sbi->s_alloc_mutex); *** DEADLOCK *** May be due to missing lock nesting notation 4 locks held by syz.3.5432/25287: #0: ffff888052540418 (sb_writers#28){.+.+}-{0:0}, at: do_sendfile+0x506/0xe80 fs/read_write.c:1253 #1: ffff88805d7c15f0 (&sb->s_type->i_mutex_key#32){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:804 [inline] #1: ffff88805d7c15f0 (&sb->s_type->i_mutex_key#32){+.+.}-{3:3}, at: udf_file_write_iter+0x77/0x6a0 fs/udf/file.c:95 #2: ffff88805d7c1408 (&ei->i_data_sem#2){++++}-{3:3}, at: udf_map_block+0x29f/0x40c0 fs/udf/inode.c:443 #3: ffff8880564d3d28 (&sbi->s_alloc_mutex){+.+.}-{3:3}, at: udf_table_new_block fs/udf/balloc.c:598 [inline] #3: ffff8880564d3d28 (&sbi->s_alloc_mutex){+.+.}-{3:3}, at: udf_new_block+0xe29/0x1a00 fs/udf/balloc.c:742 stack backtrace: CPU: 0 PID: 25287 Comm: syz.3.5432 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 Call Trace: dump_stack_lvl+0x18c/0x250 lib/dump_stack.c:106 check_deadlock kernel/locking/lockdep.c:3062 [inline] validate_chain kernel/locking/lockdep.c:3856 [inline] __lock_acquire+0x6809/0x7d80 kernel/locking/lockdep.c:5137 lock_acquire+0x19e/0x420 kernel/locking/lockdep.c:5754 __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x135/0xc80 kernel/locking/mutex.c:747 udf_table_free_blocks fs/udf/balloc.c:392 [inline] udf_free_blocks+0x9a6/0x17e0 fs/udf/balloc.c:694 udf_delete_aext+0x4f6/0xbf0 fs/udf/inode.c:2376 udf_table_new_block fs/udf/balloc.c:662 [inline] udf_new_block+0x127b/0x1a00 fs/udf/balloc.c:742 inode_getblk fs/udf/inode.c:899 [inline] udf_map_block+0x127b/0x40c0 fs/udf/inode.c:451 __udf_get_block+0x53/0x250 fs/udf/inode.c:465 __block_write_begin_int+0x571/0x1b00 fs/buffer.c:2124 __block_write_begin fs/buffer.c:2173 [inline] block_write_begin+0x9a/0x1e0 fs/buffer.c:2234 udf_write_begin+0x1c0/0x430 fs/udf/inode.c:261 generic_perform_write+0x2fe/0x5c0 mm/filemap.c:4036 __generic_file_write_iter+0x1ac/0x230 mm/filemap.c:4128 udf_file_write_iter+0x2f0/0x6a0 fs/udf/file.c:111 do_iter_readv_writev fs/read_write.c:-1 [inline] do_iter_write+0x747/0xc50 fs/read_write.c:860 iter_file_splice_write+0x6b6/0xcf0 fs/splice.c:736 do_splice_from fs/splice.c:933 [inline] direct_splice_actor+0xe8/0x130 fs/splice.c:1142 splice_direct_to_actor+0x30b/0x8e0 fs/splice.c:1088 do_splice_direct+0x1d5/0x2f0 fs/splice.c:1194 do_sendfile+0x52b/0xe80 fs/read_write.c:1254 __do_sys_sendfile64 fs/read_write.c:1322 [inline] __se_sys_sendfile64+0x145/0x1a0 fs/read_write.c:1308 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fe6b019de59 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fe6b0ff9028 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 00007fe6b0425fa0 RCX: 00007fe6b019de59 RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000004 RBP: 00007fe6b0233e6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000800000009 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fe6b0426038 R14: 00007fe6b0425fa0 R15: 00007ffcd41a3018