============================================ WARNING: possible recursive locking detected syzkaller #0 Not tainted -------------------------------------------- syz.0.0/5322 is trying to acquire lock: ffff88801182b528 (&sbi->s_alloc_mutex){+.+.}-{4:4}, at: udf_table_free_blocks fs/udf/balloc.c:375 [inline] ffff88801182b528 (&sbi->s_alloc_mutex){+.+.}-{4:4}, at: udf_free_blocks+0x9e2/0x17f0 fs/udf/balloc.c:677 but task is already holding lock: ffff88801182b528 (&sbi->s_alloc_mutex){+.+.}-{4:4}, at: udf_table_prealloc_blocks fs/udf/balloc.c:516 [inline] ffff88801182b528 (&sbi->s_alloc_mutex){+.+.}-{4:4}, at: udf_prealloc_blocks+0x8d0/0x10b0 fs/udf/balloc.c:701 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.0.0/5322: #0: ffff888034a6e420 (sb_writers#12){.+.+}-{0:0}, at: vfs_coredump+0x1db5/0x2a60 fs/coredump.c:1170 #1: ffff888043315be0 (&sb->s_type->i_mutex_key#20){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:980 [inline] #1: ffff888043315be0 (&sb->s_type->i_mutex_key#20){+.+.}-{4:4}, at: udf_file_write_iter+0x6e/0x6c0 fs/udf/file.c:95 #2: ffff888043315a10 (&ei->i_data_sem#2){++++}-{4:4}, at: udf_map_block+0x283/0x45f0 fs/udf/inode.c:446 #3: ffff88801182b528 (&sbi->s_alloc_mutex){+.+.}-{4:4}, at: udf_table_prealloc_blocks fs/udf/balloc.c:516 [inline] #3: ffff88801182b528 (&sbi->s_alloc_mutex){+.+.}-{4:4}, at: udf_prealloc_blocks+0x8d0/0x10b0 fs/udf/balloc.c:701 stack backtrace: CPU: 0 UID: 0 PID: 5322 Comm: syz.0.0 Not tainted syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 Call Trace: dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 print_deadlock_bug+0x28b/0x2a0 kernel/locking/lockdep.c:3041 check_deadlock kernel/locking/lockdep.c:3093 [inline] validate_chain+0x1a3f/0x2140 kernel/locking/lockdep.c:3895 __lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5237 lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 __mutex_lock_common kernel/locking/mutex.c:598 [inline] __mutex_lock+0x187/0x1350 kernel/locking/mutex.c:760 udf_table_free_blocks fs/udf/balloc.c:375 [inline] udf_free_blocks+0x9e2/0x17f0 fs/udf/balloc.c:677 udf_delete_aext+0x4df/0xbc0 fs/udf/inode.c:2383 udf_table_prealloc_blocks fs/udf/balloc.c:543 [inline] udf_prealloc_blocks+0xb7e/0x10b0 fs/udf/balloc.c:701 udf_prealloc_extents fs/udf/inode.c:1060 [inline] inode_getblk fs/udf/inode.c:918 [inline] udf_map_block+0x1f70/0x45f0 fs/udf/inode.c:454 __udf_get_block+0x52/0x250 fs/udf/inode.c:468 __block_write_begin_int+0x6b5/0x1900 fs/buffer.c:2145 block_write_begin+0x8a/0x120 fs/buffer.c:2256 udf_write_begin+0x115/0x270 fs/udf/inode.c:262 generic_perform_write+0x2c5/0x900 mm/filemap.c:4242 udf_file_write_iter+0x2d5/0x6c0 fs/udf/file.c:111 __kernel_write_iter+0x428/0x910 fs/read_write.c:619 dump_emit_page fs/coredump.c:1298 [inline] dump_user_range+0x8a0/0xc90 fs/coredump.c:1372 elf_core_dump+0x3369/0x3960 fs/binfmt_elf.c:2111 coredump_write+0x116c/0x1900 fs/coredump.c:1049 vfs_coredump+0x1db5/0x2a60 fs/coredump.c:1170 get_signal+0x1108/0x1340 kernel/signal.c:3019 arch_do_signal_or_restart+0xa0/0x790 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop+0x72/0x130 kernel/entry/common.c:40 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline] do_syscall_64+0x2bd/0xfa0 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f935198efc9 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:00007f93527d5038 EFLAGS: 00000246 ORIG_RAX: 0000000000000148 RAX: ffffffffffffffe5 RBX: 00007f9351be5fa0 RCX: 00007f935198efc9 RDX: 0000000000000001 RSI: 00002000000000c0 RDI: 0000000000000009 RBP: 00007f9351a11f91 R08: 0000000000001800 R09: 0000000000000001 R10: 00000000ffffffff R11: 0000000000000246 R12: 0000000000000000 R13: 00007f9351be6038 R14: 00007f9351be5fa0 R15: 00007fffa236ff08