syzbot


BUG: MAX_LOCK_DEPTH too low! (5)

Status: upstream: reported C repro on 2024/11/10 09:16
Subsystems: btrfs
[Documentation on labels]
Reported-by: syzbot+c589dd1d06df2d690925@syzkaller.appspotmail.com
First crash: 11d, last: 4d22h
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [btrfs?] BUG: MAX_LOCK_DEPTH too low! (5) 0 (1) 2024/11/10 09:16
Similar bugs (4)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream BUG: MAX_LOCK_DEPTH too low! net 1 2392d 2392d 5/28 fixed on 2018/05/17 10:02
upstream BUG: MAX_LOCK_DEPTH too low! (3) net s390 C done 18 1004d 1013d 22/28 fixed on 2023/02/24 13:50
upstream BUG: MAX_LOCK_DEPTH too low! (2) net C done 5 2319d 2350d 13/28 fixed on 2019/11/11 16:48
upstream BUG: MAX_LOCK_DEPTH too low! (4) bcachefs C error 1364 97d 193d 27/28 fixed on 2024/08/25 15:26

Sample crash report:
 </TASK>
BTRFS error (device loop0): failed to run delayed ref for logical 5365760 num_bytes 4096 type 176 action 2 ref_mod 1: -12
BTRFS error (device loop0 state A): Transaction aborted (error -12)
BTRFS: error (device loop0 state A) in btrfs_run_delayed_refs:2215: errno=-12 Out of memory
BTRFS info (device loop0 state EA): forced readonly
BUG: MAX_LOCK_DEPTH too low!
turning off the locking correctness validator.
depth: 48  max: 48!
48 locks held by syz-executor281/5311:
 #0: ffff8880346b4420 (sb_writers#10){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2931 [inline]
 #0: ffff8880346b4420 (sb_writers#10){.+.+}-{0:0}, at: vfs_writev+0x2d1/0xba0 fs/read_write.c:1062
 #1: ffff888045ee1638 (&sb->s_type->i_mutex_key#15){+.+.}-{3:3}, at: inode_trylock include/linux/fs.h:835 [inline]
 #1: ffff888045ee1638 (&sb->s_type->i_mutex_key#15){+.+.}-{3:3}, at: btrfs_inode_lock+0x87/0xe0 fs/btrfs/inode.c:357
 #2: ffff888043cebe18 (btrfs-tree-01){++++}-{3:3}, at: btrfs_try_tree_read_lock+0x1c/0x240 fs/btrfs/locking.c:157
 #3: ffff888043cebe18 (btrfs-tree-01){++++}-{3:3}, at: btrfs_try_tree_read_lock+0x1c/0x240 fs/btrfs/locking.c:157
 #4: ffff888043cebe18 (btrfs-tree-01){++++}-{3:3}, at: btrfs_try_tree_read_lock+0x1c/0x240 fs/btrfs/locking.c:157
 #5: ffff888043cebe18 (btrfs-tree-01){++++}-{3:3}, at: btrfs_try_tree_read_lock+0x1c/0x240 fs/btrfs/locking.c:157
 #6: ffff888043cebe18 (btrfs-tree-01){++++}-{3:3}, at: btrfs_try_tree_read_lock+0x1c/0x240 fs/btrfs/locking.c:157
 #7: ffff888043cebe18 (btrfs-tree-01){++++}-{3:3}, at: btrfs_try_tree_read_lock+0x1c/0x240 fs/btrfs/locking.c:157
 #8: ffff888043cebe18 (btrfs-tree-01){++++}-{3:3}, at: btrfs_try_tree_read_lock+0x1c/0x240 fs/btrfs/locking.c:157
 #9: ffff888043cebe18 (btrfs-tree-01){++++}-{3:3}, at: btrfs_try_tree_read_lock+0x1c/0x240 fs/btrfs/locking.c:157
 #10: ffff888043cebe18 (btrfs-tree-01){++++}-{3:3}, at: btrfs_try_tree_read_lock+0x1c/0x240 fs/btrfs/locking.c:157
 #11: ffff888043cebe18 (btrfs-tree-01){++++}-{3:3}, at: btrfs_try_tree_read_lock+0x1c/0x240 fs/btrfs/locking.c:157
 #12: ffff888043cebe18 (btrfs-tree-01){++++}-{3:3}, at: btrfs_try_tree_read_lock+0x1c/0x240 fs/btrfs/locking.c:157
 #13: ffff888043cebe18 (btrfs-tree-01){++++}-{3:3}, at: btrfs_try_tree_read_lock+0x1c/0x240 fs/btrfs/locking.c:157
 #14: ffff888043cebe18 (btrfs-tree-01){++++}-{3:3}, at: btrfs_try_tree_read_lock+0x1c/0x240 fs/btrfs/locking.c:157
 #15: ffff888043cebe18 (btrfs-tree-01){++++}-{3:3}, at: btrfs_try_tree_read_lock+0x1c/0x240 fs/btrfs/locking.c:157
 #16: ffff888043cebe18 (btrfs-tree-01){++++}-{3:3}, at: btrfs_try_tree_read_lock+0x1c/0x240 fs/btrfs/locking.c:157
 #17: ffff888043cebe18 (btrfs-tree-01){++++}-{3:3}, at: btrfs_try_tree_read_lock+0x1c/0x240 fs/btrfs/locking.c:157
 #18: ffff888043cebe18 (btrfs-tree-01){++++}-{3:3}, at: btrfs_try_tree_read_lock+0x1c/0x240 fs/btrfs/locking.c:157
 #19: ffff888043cebe18 (btrfs-tree-01){++++}-{3:3}, at: btrfs_try_tree_read_lock+0x1c/0x240 fs/btrfs/locking.c:157
 #20: ffff888043cebe18 (btrfs-tree-01){++++}-{3:3}, at: btrfs_try_tree_read_lock+0x1c/0x240 fs/btrfs/locking.c:157
 #21: ffff888043cebe18 (btrfs-tree-01){++++}-{3:3}, at: btrfs_try_tree_read_lock+0x1c/0x240 fs/btrfs/locking.c:157
 #22: ffff888043cebe18 (btrfs-tree-01){++++}-{3:3}, at: btrfs_try_tree_read_lock+0x1c/0x240 fs/btrfs/locking.c:157
 #23: ffff888043cebe18 (btrfs-tree-01){++++}-{3:3}, at: btrfs_try_tree_read_lock+0x1c/0x240 fs/btrfs/locking.c:157
 #24: ffff888043cebe18 (btrfs-tree-01){++++}-{3:3}, at: btrfs_try_tree_read_lock+0x1c/0x240 fs/btrfs/locking.c:157
 #25: ffff888043cebe18 (btrfs-tree-01){++++}-{3:3}, at: btrfs_try_tree_read_lock+0x1c/0x240 fs/btrfs/locking.c:157
 #26: ffff888043cebe18 (btrfs-tree-01){++++}-{3:3}, at: btrfs_try_tree_read_lock+0x1c/0x240 fs/btrfs/locking.c:157
 #27: ffff888043cebe18 (btrfs-tree-01){++++}-{3:3}, at: btrfs_try_tree_read_lock+0x1c/0x240 fs/btrfs/locking.c:157
 #28: ffff888043cebe18 (btrfs-tree-01){++++}-{3:3}, at: btrfs_try_tree_read_lock+0x1c/0x240 fs/btrfs/locking.c:157
 #29: ffff888043cebe18 (btrfs-tree-01){++++}-{3:3}, at: btrfs_try_tree_read_lock+0x1c/0x240 fs/btrfs/locking.c:157
 #30: ffff888043cebe18 (btrfs-tree-01){++++}-{3:3}, at: btrfs_try_tree_read_lock+0x1c/0x240 fs/btrfs/locking.c:157
 #31: ffff888043cebe18 (btrfs-tree-01){++++}-{3:3}, at: btrfs_try_tree_read_lock+0x1c/0x240 fs/btrfs/locking.c:157
 #32: ffff888043cebe18 (btrfs-tree-01){++++}-{3:3}, at: btrfs_try_tree_read_lock+0x1c/0x240 fs/btrfs/locking.c:157
 #33: ffff888043cebe18 (btrfs-tree-01){++++}-{3:3}, at: btrfs_try_tree_read_lock+0x1c/0x240 fs/btrfs/locking.c:157
 #34: ffff888043cebe18 (btrfs-tree-01){++++}-{3:3}, at: btrfs_try_tree_read_lock+0x1c/0x240 fs/btrfs/locking.c:157
 #35: ffff888043cebe18 (btrfs-tree-01){++++}-{3:3}, at: btrfs_try_tree_read_lock+0x1c/0x240 fs/btrfs/locking.c:157
 #36: ffff888043cebe18 (btrfs-tree-01){++++}-{3:3}, at: btrfs_try_tree_read_lock+0x1c/0x240 fs/btrfs/locking.c:157
 #37: ffff888043cebe18 (btrfs-tree-01){++++}-{3:3}, at: btrfs_try_tree_read_lock+0x1c/0x240 fs/btrfs/locking.c:157
 #38: ffff888043cebe18 (btrfs-tree-01){++++}-{3:3}, at: btrfs_try_tree_read_lock+0x1c/0x240 fs/btrfs/locking.c:157
 #39: ffff888043cebe18 (btrfs-tree-01){++++}-{3:3}, at: btrfs_try_tree_read_lock+0x1c/0x240 fs/btrfs/locking.c:157
 #40: ffff888043cebe18 (btrfs-tree-01){++++}-{3:3}, at: btrfs_try_tree_read_lock+0x1c/0x240 fs/btrfs/locking.c:157
 #41: ffff888043cebe18 (btrfs-tree-01){++++}-{3:3}, at: btrfs_try_tree_read_lock+0x1c/0x240 fs/btrfs/locking.c:157
 #42: ffff888043cebe18 (btrfs-tree-01){++++}-{3:3}, at: btrfs_try_tree_read_lock+0x1c/0x240 fs/btrfs/locking.c:157
 #43: ffff888043cebe18 (btrfs-tree-01){++++}-{3:3}, at: btrfs_try_tree_read_lock+0x1c/0x240 fs/btrfs/locking.c:157
 #44: ffff888043cebe18 (btrfs-tree-01){++++}-{3:3}, at: btrfs_try_tree_read_lock+0x1c/0x240 fs/btrfs/locking.c:157
 #45: ffff888043cebe18 (btrfs-tree-01){++++}-{3:3}, at: btrfs_try_tree_read_lock+0x1c/0x240 fs/btrfs/locking.c:157
 #46: ffff888043cebe18 (btrfs-tree-01){++++}-{3:3}, at: btrfs_try_tree_read_lock+0x1c/0x240 fs/btrfs/locking.c:157
 #47: ffffffff8e937da0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline]
 #47: ffffffff8e937da0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #47: ffffffff8e937da0 (rcu_read_lock){....}-{1:2}, at: find_extent_buffer_nolock+0x21/0x320 fs/btrfs/extent_io.c:1615
INFO: lockdep is turned off.
CPU: 0 UID: 0 PID: 5311 Comm: syz-executor281 Not tainted 6.12.0-rc6-syzkaller-00077-g2e1b3cc9d7f7 #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
 __lock_acquire+0x10ee/0x2050
 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5825
 rcu_lock_acquire include/linux/rcupdate.h:337 [inline]
 rcu_read_lock include/linux/rcupdate.h:849 [inline]
 find_extent_buffer_nolock+0x3e/0x320 fs/btrfs/extent_io.c:1615
 find_extent_buffer+0x24/0x340 fs/btrfs/extent_io.c:2710
 read_block_for_search+0x348/0x920 fs/btrfs/ctree.c:1540
 btrfs_search_slot+0x120d/0x30d0 fs/btrfs/ctree.c:2200
 btrfs_lookup_file_extent+0x14c/0x210 fs/btrfs/file-item.c:267
 can_nocow_extent+0x1c5/0x940 fs/btrfs/inode.c:7055
 btrfs_check_nocow_lock+0x274/0x400 fs/btrfs/file.c:1106
 btrfs_buffered_write+0x63f/0x1360 fs/btrfs/file.c:1280
 btrfs_do_write_iter+0x279/0x760 fs/btrfs/file.c:1508
 do_iter_readv_writev+0x600/0x880
 vfs_writev+0x376/0xba0 fs/read_write.c:1064
 do_pwritev fs/read_write.c:1165 [inline]
 __do_sys_pwritev2 fs/read_write.c:1224 [inline]
 __se_sys_pwritev2+0x1ca/0x2d0 fs/read_write.c:1215
 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: 0033:0x7effcb021b49
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 d1 1a 00 00 90 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffcc8a399f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000148
RAX: ffffffffffffffda RBX: 00007ffcc8a39a30 RCX: 00007effcb021b49
RDX: 0000000000000001 RSI: 00000000200001c0 RDI: 0000000000000005
RBP: 0000000000000001 R08: 0000000000000009 R09: 0000000000000008
R10: 0000000000000002 R11: 0000000000000246 R12: 00007ffcc8a39a60
R13: 00007ffcc8a39b40 R14: 431bde82d7b634db R15: 00007effcb06301d
 </TASK>

Crashes (5):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/11/06 11:05 upstream 2e1b3cc9d7f7 3a465482 .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] [mounted in repro] ci-snapshot-upstream-root BUG: MAX_LOCK_DEPTH too low!
2024/11/06 10:24 upstream 2e1b3cc9d7f7 3a465482 .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] [mounted in repro] ci-snapshot-upstream-root BUG: MAX_LOCK_DEPTH too low!
2024/11/06 09:44 upstream 2e1b3cc9d7f7 3a465482 .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] [mounted in repro] ci-snapshot-upstream-root BUG: MAX_LOCK_DEPTH too low!
2024/11/13 03:20 upstream 3022e9d00ebe 62026c85 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root BUG: MAX_LOCK_DEPTH too low!
2024/11/06 09:04 upstream 2e1b3cc9d7f7 3a465482 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root BUG: MAX_LOCK_DEPTH too low!
* Struck through repros no longer work on HEAD.