syzbot


possible deadlock in udf_free_blocks

Status: upstream: reported on 2024/11/04 17:57
Subsystems: udf
[Documentation on labels]
Reported-by: syzbot+d472c32c5dd4cd2fb5c5@syzkaller.appspotmail.com
First crash: 20d, last: 1d02h
Discussions (2)
Title Replies (including bot) Last reply
[syzbot] Monthly udf report (Nov 2024) 0 (1) 2024/11/18 10:47
[syzbot] [udf?] possible deadlock in udf_free_blocks 0 (1) 2024/11/04 17:57

Sample crash report:
loop0: detected capacity change from 0 to 2048
UDF-fs: INFO Mounting volume 'LiuxUDF', timestamp 2022/11/22 14:59 (1000)
=======================================================
WARNING: The mand mount option has been deprecated and
         and is ignored by this kernel. Remove the mand
         option from the mount to silence this warning.
=======================================================
IPVS: persistence engine module ip_vs_pe_si not found
============================================
WARNING: possible recursive locking detected
6.12.0-syzkaller-00971-g158f238aa69d #0 Not tainted
--------------------------------------------
syz.0.0/5327 is trying to acquire lock:
ffff88803f762128 (&sbi->s_alloc_mutex){+.+.}-{3:3}, at: udf_table_free_blocks fs/udf/balloc.c:375 [inline]
ffff88803f762128 (&sbi->s_alloc_mutex){+.+.}-{3:3}, at: udf_free_blocks+0x9ff/0x2270 fs/udf/balloc.c:677

but task is already holding lock:
ffff88803f762128 (&sbi->s_alloc_mutex){+.+.}-{3:3}, at: udf_table_new_block fs/udf/balloc.c:581 [inline]
ffff88803f762128 (&sbi->s_alloc_mutex){+.+.}-{3:3}, at: udf_new_block+0xf81/0x21c0 fs/udf/balloc.c:725

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.0.0/5327:
 #0: ffff88801210a420 (sb_writers#11){.+.+}-{0:0}, at: direct_splice_actor+0x49/0x220 fs/splice.c:1163
 #1: ffff888043f74f60 (&sb->s_type->i_mutex_key#19){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:818 [inline]
 #1: ffff888043f74f60 (&sb->s_type->i_mutex_key#19){+.+.}-{3:3}, at: udf_file_write_iter+0x6f/0x660 fs/udf/file.c:95
 #2: ffff888043f74d90 (&ei->i_data_sem#2){++++}-{3:3}, at: udf_map_block+0x3b7/0x5340 fs/udf/inode.c:439
 #3: ffff88803f762128 (&sbi->s_alloc_mutex){+.+.}-{3:3}, at: udf_table_new_block fs/udf/balloc.c:581 [inline]
 #3: ffff88803f762128 (&sbi->s_alloc_mutex){+.+.}-{3:3}, at: udf_new_block+0xf81/0x21c0 fs/udf/balloc.c:725

stack backtrace:
CPU: 0 UID: 0 PID: 5327 Comm: syz.0.0 Not tainted 6.12.0-syzkaller-00971-g158f238aa69d #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 print_deadlock_bug+0x483/0x620 kernel/locking/lockdep.c:3037
 check_deadlock kernel/locking/lockdep.c:3089 [inline]
 validate_chain+0x15e2/0x5920 kernel/locking/lockdep.c:3891
 __lock_acquire+0x1384/0x2050 kernel/locking/lockdep.c:5202
 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5825
 __mutex_lock_common kernel/locking/mutex.c:608 [inline]
 __mutex_lock+0x136/0xd70 kernel/locking/mutex.c:752
 udf_table_free_blocks fs/udf/balloc.c:375 [inline]
 udf_free_blocks+0x9ff/0x2270 fs/udf/balloc.c:677
 udf_delete_aext+0x70a/0xed0 fs/udf/inode.c:2372
 udf_table_new_block fs/udf/balloc.c:645 [inline]
 udf_new_block+0x18ba/0x21c0 fs/udf/balloc.c:725
 inode_getblk fs/udf/inode.c:894 [inline]
 udf_map_block+0x1c9a/0x5340 fs/udf/inode.c:447
 __udf_get_block+0x126/0x410 fs/udf/inode.c:461
 __block_write_begin_int+0x50c/0x1a70 fs/buffer.c:2122
 block_write_begin+0x8f/0x120 fs/buffer.c:2232
 udf_write_begin+0x104/0x350 fs/udf/inode.c:256
 generic_perform_write+0x344/0x6d0 mm/filemap.c:4056
 __generic_file_write_iter+0x1b5/0x230 mm/filemap.c:4154
 udf_file_write_iter+0x2fc/0x660 fs/udf/file.c:111
 iter_file_splice_write+0xbfa/0x1510 fs/splice.c:743
 do_splice_from fs/splice.c:941 [inline]
 direct_splice_actor+0x11b/0x220 fs/splice.c:1164
 splice_direct_to_actor+0x586/0xc80 fs/splice.c:1108
 do_splice_direct_actor fs/splice.c:1207 [inline]
 do_splice_direct+0x289/0x3e0 fs/splice.c:1233
 do_sendfile+0x564/0x8a0 fs/read_write.c:1363
 __do_sys_sendfile64 fs/read_write.c:1424 [inline]
 __se_sys_sendfile64+0x17c/0x1e0 fs/read_write.c:1410
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f87eef7e759
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:00007f87efcd4038 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00007f87ef135f80 RCX: 00007f87eef7e759
RDX: 0000000000000000 RSI: 0000000000000006 RDI: 0000000000000006
RBP: 00007f87eeff175e R08: 0000000000000000 R09: 0000000000000000
R10: 0000000800000009 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f87ef135f80 R15: 00007ffd9fcf3528
 </TASK>

Crashes (5):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/11/20 04:16 upstream 158f238aa69d 7d02db5a .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root possible deadlock in udf_free_blocks
2024/11/19 08:36 upstream 9fb2cfa4635a 571351cb .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root possible deadlock in udf_free_blocks
2024/11/14 10:54 upstream 0a9b9d17f3a7 a8c99394 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root possible deadlock in udf_free_blocks
2024/11/13 06:41 upstream 3022e9d00ebe 62026c85 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root possible deadlock in udf_free_blocks
2024/10/31 17:50 upstream 0fc810ae3ae1 96eb609f .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root possible deadlock in udf_free_blocks
* Struck through repros no longer work on HEAD.