loop0: detected capacity change from 0 to 2048 UDF-fs: error (device loop0): udf_read_tagged: read failed, block=2362, location=2362 UDF-fs: error (device loop0): udf_read_tagged: tag checksum failed, block 99: 0x27 != 0x4d UDF-fs: error (device loop0): udf_read_tagged: tag checksum failed, block 160: 0xd2 != 0xd4 UDF-fs: INFO Mounting volume 'LinuxUDF', timestamp 2022/11/22 14:59 (1000) ============================================ WARNING: possible recursive locking detected 6.15.0-rc3-syzkaller-00001-g9d7a0577c9db #0 Not tainted -------------------------------------------- syz.0.0/5322 is trying to acquire lock: ffff888043edcd28 (&sbi->s_alloc_mutex){+.+.}-{4:4}, at: udf_table_free_blocks fs/udf/balloc.c:375 [inline] ffff888043edcd28 (&sbi->s_alloc_mutex){+.+.}-{4:4}, at: udf_free_blocks+0xa28/0x22b0 fs/udf/balloc.c:677 but task is already holding lock: ffff888043edcd28 (&sbi->s_alloc_mutex){+.+.}-{4:4}, at: udf_table_prealloc_blocks fs/udf/balloc.c:516 [inline] ffff888043edcd28 (&sbi->s_alloc_mutex){+.+.}-{4:4}, at: udf_prealloc_blocks+0x864/0x1470 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 5 locks held by syz.0.0/5322: #0: ffff888040506fe0 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_trylock include/linux/mmap_lock.h:203 [inline] #0: ffff888040506fe0 (&mm->mmap_lock){++++}-{4:4}, at: get_mmap_lock_carefully mm/memory.c:6346 [inline] #0: ffff888040506fe0 (&mm->mmap_lock){++++}-{4:4}, at: lock_mm_and_find_vma+0x32/0x2f0 mm/memory.c:6406 #1: ffff888034096518 (sb_pagefaults){.+.+}-{0:0}, at: do_page_mkwrite+0x159/0x340 mm/memory.c:3287 #2: ffff888044371760 (mapping.invalidate_lock#3){++++}-{4:4}, at: filemap_invalidate_lock_shared include/linux/fs.h:922 [inline] #2: ffff888044371760 (mapping.invalidate_lock#3){++++}-{4:4}, at: udf_page_mkwrite+0x27a/0x8d0 fs/udf/file.c:50 #3: ffff8880443713f0 (&ei->i_data_sem#2){++++}-{4:4}, at: udf_map_block+0x3b9/0x55c0 fs/udf/inode.c:439 #4: ffff888043edcd28 (&sbi->s_alloc_mutex){+.+.}-{4:4}, at: udf_table_prealloc_blocks fs/udf/balloc.c:516 [inline] #4: ffff888043edcd28 (&sbi->s_alloc_mutex){+.+.}-{4:4}, at: udf_prealloc_blocks+0x864/0x1470 fs/udf/balloc.c:701 stack backtrace: CPU: 0 UID: 0 PID: 5322 Comm: syz.0.0 Not tainted 6.15.0-rc3-syzkaller-00001-g9d7a0577c9db #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 lib/dump_stack.c:94 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 print_deadlock_bug+0x2be/0x2d0 kernel/locking/lockdep.c:3042 check_deadlock kernel/locking/lockdep.c:3094 [inline] validate_chain+0x928/0x24e0 kernel/locking/lockdep.c:3896 __lock_acquire+0xad5/0xd80 kernel/locking/lockdep.c:5235 lock_acquire+0x116/0x2f0 kernel/locking/lockdep.c:5866 __mutex_lock_common kernel/locking/mutex.c:601 [inline] __mutex_lock+0x1a5/0x10c0 kernel/locking/mutex.c:746 udf_table_free_blocks fs/udf/balloc.c:375 [inline] udf_free_blocks+0xa28/0x22b0 fs/udf/balloc.c:677 udf_delete_aext+0x6f3/0xec0 fs/udf/inode.c:2373 udf_table_prealloc_blocks fs/udf/balloc.c:543 [inline] udf_prealloc_blocks+0xd04/0x1470 fs/udf/balloc.c:701 udf_prealloc_extents fs/udf/inode.c:1053 [inline] inode_getblk fs/udf/inode.c:911 [inline] udf_map_block+0x2827/0x55c0 fs/udf/inode.c:447 __udf_get_block+0x128/0x410 fs/udf/inode.c:461 __block_write_begin_int+0x691/0x1930 fs/buffer.c:2116 udf_page_mkwrite+0x5bf/0x8d0 fs/udf/file.c:65 do_page_mkwrite+0x159/0x340 mm/memory.c:3287 wp_page_shared mm/memory.c:3688 [inline] do_wp_page+0x2b7e/0x5dc0 mm/memory.c:3907 handle_pte_fault+0xfaf/0x61c0 mm/memory.c:6013 __handle_mm_fault mm/memory.c:6140 [inline] handle_mm_fault+0x1129/0x1bf0 mm/memory.c:6309 do_user_addr_fault arch/x86/mm/fault.c:1388 [inline] handle_page_fault arch/x86/mm/fault.c:1480 [inline] exc_page_fault+0x2bb/0x920 arch/x86/mm/fault.c:1538 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623 RIP: 0010:rep_movs_alternative+0x4a/0x90 arch/x86/lib/copy_user_64.S:74 Code: cc cc cc 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 48 8b 06 48 89 07 48 83 c6 08 48 83 c7 08 83 e9 08 74 db 83 f9 08 73 e8 eb c5 a4 c3 cc cc cc cc 48 8b 06 48 89 07 48 8d 47 08 48 83 e0 f8 48 RSP: 0000:ffffc9000d517ac8 EFLAGS: 00050246 RAX: ffffffff85041b01 RBX: 0000200000018040 RCX: 0000000000000040 RDX: 0000000000000000 RSI: ffffc9000d517b60 RDI: 0000200000018000 RBP: ffffc9000d517c10 R08: ffffc9000d517b9f R09: 1ffff92001aa2f73 R10: dffffc0000000000 R11: fffff52001aa2f74 R12: 0000000000000040 R13: 00007ffffffff000 R14: ffffc9000d517b60 R15: 0000200000018000 copy_user_generic arch/x86/include/asm/uaccess_64.h:126 [inline] raw_copy_to_user arch/x86/include/asm/uaccess_64.h:147 [inline] _inline_copy_to_user include/linux/uaccess.h:197 [inline] _copy_to_user+0x8b/0xb0 lib/usercopy.c:26 copy_to_user include/linux/uaccess.h:225 [inline] rng_dev_read+0x3dc/0x720 drivers/char/hw_random/core.c:258 do_loop_readv_writev fs/read_write.c:845 [inline] vfs_readv+0x6be/0xa80 fs/read_write.c:1018 do_preadv fs/read_write.c:1130 [inline] __do_sys_preadv fs/read_write.c:1177 [inline] __se_sys_preadv fs/read_write.c:1172 [inline] __x64_sys_preadv+0x1ba/0x2d0 fs/read_write.c:1172 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xf3/0x210 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f5d4c18e169 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:00007f5d4d0da038 EFLAGS: 00000246 ORIG_RAX: 0000000000000127 RAX: ffffffffffffffda RBX: 00007f5d4c3b5fa0 RCX: 00007f5d4c18e169 RDX: 0000000000000001 RSI: 0000200000000580 RDI: 000000000000000c RBP: 00007f5d4c210a68 R08: 0000000000000000 R09: 0000000000000000 R10: 00000000fffffff8 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f5d4c3b5fa0 R15: 00007ffc3e8fde58 ---------------- Code disassembly (best guess): 0: cc int3 1: cc int3 2: cc int3 3: 66 2e 0f 1f 84 00 00 cs nopw 0x0(%rax,%rax,1) a: 00 00 00 d: 0f 1f 00 nopl (%rax) 10: 48 8b 06 mov (%rsi),%rax 13: 48 89 07 mov %rax,(%rdi) 16: 48 83 c6 08 add $0x8,%rsi 1a: 48 83 c7 08 add $0x8,%rdi 1e: 83 e9 08 sub $0x8,%ecx 21: 74 db je 0xfffffffe 23: 83 f9 08 cmp $0x8,%ecx 26: 73 e8 jae 0x10 28: eb c5 jmp 0xffffffef * 2a: f3 a4 rep movsb %ds:(%rsi),%es:(%rdi) <-- trapping instruction 2c: c3 ret 2d: cc int3 2e: cc int3 2f: cc int3 30: cc int3 31: 48 8b 06 mov (%rsi),%rax 34: 48 89 07 mov %rax,(%rdi) 37: 48 8d 47 08 lea 0x8(%rdi),%rax 3b: 48 83 e0 f8 and $0xfffffffffffffff8,%rax 3f: 48 rex.W