syzbot

 sign-in | mailing list | source | docs
🐞 Open [833]
🐞 Fixed [87]
🐞 Invalid [1218]
⬇ Missing Backports [132]
≡ Crashes
Kernel Health Bugs/Month Bug Lifetimes Fuzzing
💬 Send us feedback

possible deadlock in ocfs2_remove_btree_range

Status: auto-obsoleted due to no activity on 2024/12/24 02:14
Reported-by: syzbot+30074851a5c3ae81f5de@syzkaller.appspotmail.com
First crash: 513d, last: 513d
▶ ▼ Similar bugs (4)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream possible deadlock in ocfs2_remove_btree_range (2) ocfs2 4 1 97d 93d 0/29 upstream: reported on 2025/11/09 02:45
linux-6.1 possible deadlock in ocfs2_remove_btree_range 4 6 5h38m 11d 0/3 upstream: reported on 2026/01/29 20:10
linux-5.15 possible deadlock in ocfs2_remove_btree_range (2) 4 1 2d05h 2d05h 0/3 upstream: reported on 2026/02/08 13:36
upstream possible deadlock in ocfs2_remove_btree_range ocfs2 4 2 443d 470d 0/29 auto-obsoleted due to no activity on 2025/03/03 19:57

Sample crash report:
======================================================
WARNING: possible circular locking dependency detected
5.15.167-syzkaller #0 Not tainted
------------------------------------------------------
syz.1.340/5274 is trying to acquire lock:
ffff888061a15108 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#6){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:789 [inline]
ffff888061a15108 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#6){+.+.}-{3:3}, at: ocfs2_remove_btree_range+0x733/0x18a0 fs/ocfs2/alloc.c:5735

but task is already holding lock:
ffff888061a16a20 (&oi->ip_alloc_sem){++++}-{3:3}, at: ocfs2_truncate_file+0x345/0x14f0 fs/ocfs2/file.c:467

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #6 (&oi->ip_alloc_sem){++++}-{3:3}:
       lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
       down_write+0x38/0x60 kernel/locking/rwsem.c:1551
       ocfs2_page_mkwrite+0x301/0xbd0 fs/ocfs2/mmap.c:142
       do_page_mkwrite+0x1a9/0x440 mm/memory.c:2892
       wp_page_shared+0x179/0x690 mm/memory.c:3229
       handle_pte_fault mm/memory.c:4638 [inline]
       __handle_mm_fault mm/memory.c:4755 [inline]
       handle_mm_fault+0x2a3d/0x5960 mm/memory.c:4853
       do_user_addr_fault arch/x86/mm/fault.c:1357 [inline]
       handle_page_fault arch/x86/mm/fault.c:1445 [inline]
       exc_page_fault+0x271/0x700 arch/x86/mm/fault.c:1501
       asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:568

-> #5 (sb_pagefaults#2){.+.+}-{0:0}:
       lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
       percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
       __sb_start_write include/linux/fs.h:1811 [inline]
       sb_start_pagefault include/linux/fs.h:1910 [inline]
       ocfs2_page_mkwrite+0x1d9/0xbd0 fs/ocfs2/mmap.c:122
       do_page_mkwrite+0x1a9/0x440 mm/memory.c:2892
       wp_page_shared+0x179/0x690 mm/memory.c:3229
       handle_pte_fault mm/memory.c:4638 [inline]
       __handle_mm_fault mm/memory.c:4755 [inline]
       handle_mm_fault+0x2a3d/0x5960 mm/memory.c:4853
       do_user_addr_fault arch/x86/mm/fault.c:1357 [inline]
       handle_page_fault arch/x86/mm/fault.c:1445 [inline]
       exc_page_fault+0x271/0x700 arch/x86/mm/fault.c:1501
       asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:568

-> #4 (&mm->mmap_lock){++++}-{3:3}:
       lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
       internal_get_user_pages_fast+0x212/0x2810 mm/gup.c:2895
       iov_iter_get_pages+0x25a/0x570 lib/iov_iter.c:1544
       __bio_iov_iter_get_pages block/bio.c:1136 [inline]
       bio_iov_iter_get_pages+0x477/0x18e0 block/bio.c:1195
       iomap_dio_bio_iter+0xab9/0x1540 fs/iomap/direct-io.c:321
       __iomap_dio_rw+0xf9f/0x1f40 fs/iomap/direct-io.c:586
       iomap_dio_rw+0x38/0x80 fs/iomap/direct-io.c:672
       ext4_dio_write_iter fs/ext4/file.c:570 [inline]
       ext4_file_write_iter+0x1779/0x1990 fs/ext4/file.c:681
       do_iter_readv_writev+0x594/0x7a0
       do_iter_write+0x1e6/0x760 fs/read_write.c:855
       vfs_writev fs/read_write.c:928 [inline]
       do_pwritev+0x219/0x360 fs/read_write.c:1025
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x66/0xd0

-> #3 (&sb->s_type->i_mutex_key#9){++++}-{3:3}:
       lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
       down_read+0x45/0x2e0 kernel/locking/rwsem.c:1498
       inode_lock_shared include/linux/fs.h:799 [inline]
       ext4_bmap+0x4b/0x410 fs/ext4/inode.c:3163
       bmap+0xa1/0xd0 fs/inode.c:1791
       jbd2_journal_bmap fs/jbd2/journal.c:981 [inline]
       __jbd2_journal_erase fs/jbd2/journal.c:1796 [inline]
       jbd2_journal_flush+0x7a2/0xc90 fs/jbd2/journal.c:2502
       ext4_ioctl_checkpoint fs/ext4/ioctl.c:849 [inline]
       __ext4_ioctl fs/ext4/ioctl.c:1267 [inline]
       ext4_ioctl+0x3249/0x5b80 fs/ext4/ioctl.c:1276
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:874 [inline]
       __se_sys_ioctl+0xf1/0x160 fs/ioctl.c:860
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x66/0xd0

-> #2 (&journal->j_checkpoint_mutex){+.+.}-{3:3}:
       lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
       __mutex_lock_common+0x1da/0x25a0 kernel/locking/mutex.c:596
       mutex_lock_io_nested+0x45/0x60 kernel/locking/mutex.c:777
       jbd2_journal_flush+0x290/0xc90 fs/jbd2/journal.c:2474
       ext4_ioctl_checkpoint fs/ext4/ioctl.c:849 [inline]
       __ext4_ioctl fs/ext4/ioctl.c:1267 [inline]
       ext4_ioctl+0x3249/0x5b80 fs/ext4/ioctl.c:1276
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:874 [inline]
       __se_sys_ioctl+0xf1/0x160 fs/ioctl.c:860
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x66/0xd0

-> #1 (&journal->j_barrier){+.+.}-{3:3}:
       lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
       __mutex_lock_common+0x1da/0x25a0 kernel/locking/mutex.c:596
       __mutex_lock kernel/locking/mutex.c:729 [inline]
       mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
       jbd2_journal_lock_updates+0x2aa/0x370 fs/jbd2/transaction.c:905
       __ocfs2_flush_truncate_log+0x2e7/0x11c0 fs/ocfs2/alloc.c:6020
       ocfs2_flush_truncate_log+0x4b/0x60 fs/ocfs2/alloc.c:6067
       ocfs2_sync_fs+0x121/0x380 fs/ocfs2/super.c:403
       sync_filesystem+0x1bc/0x220 fs/sync.c:66
       generic_shutdown_super+0x6e/0x2c0 fs/super.c:448
       kill_block_super+0x7a/0xe0 fs/super.c:1425
       deactivate_locked_super+0xa0/0x110 fs/super.c:335
       cleanup_mnt+0x44e/0x500 fs/namespace.c:1143
       task_work_run+0x129/0x1a0 kernel/task_work.c:188
       tracehook_notify_resume include/linux/tracehook.h:189 [inline]
       exit_to_user_mode_loop+0x106/0x130 kernel/entry/common.c:181
       exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:214
       __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
       syscall_exit_to_user_mode+0x5d/0x240 kernel/entry/common.c:307
       do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:86
       entry_SYSCALL_64_after_hwframe+0x66/0xd0

-> #0 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#6){+.+.}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3053 [inline]
       check_prevs_add kernel/locking/lockdep.c:3172 [inline]
       validate_chain+0x1649/0x5930 kernel/locking/lockdep.c:3788
       __lock_acquire+0x1295/0x1ff0 kernel/locking/lockdep.c:5012
       lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
       down_write+0x38/0x60 kernel/locking/rwsem.c:1551
       inode_lock include/linux/fs.h:789 [inline]
       ocfs2_remove_btree_range+0x733/0x18a0 fs/ocfs2/alloc.c:5735
       ocfs2_commit_truncate+0xcb3/0x2530 fs/ocfs2/alloc.c:7339
       ocfs2_truncate_file+0xd3d/0x14f0 fs/ocfs2/file.c:505
       ocfs2_setattr+0x165e/0x1c70 fs/ocfs2/file.c:1212
       notify_change+0xc6d/0xf50 fs/attr.c:505
       do_truncate+0x21c/0x300 fs/open.c:65
       handle_truncate fs/namei.c:3265 [inline]
       do_open fs/namei.c:3612 [inline]
       path_openat+0x28a3/0x2f20 fs/namei.c:3742
       do_filp_open+0x21c/0x460 fs/namei.c:3769
       do_sys_openat2+0x13b/0x4f0 fs/open.c:1253
       do_sys_open fs/open.c:1269 [inline]
       __do_sys_creat fs/open.c:1343 [inline]
       __se_sys_creat fs/open.c:1337 [inline]
       __x64_sys_creat+0x11f/0x160 fs/open.c:1337
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x66/0xd0

other info that might help us debug this:

Chain exists of:
  &ocfs2_sysfile_lock_key[args->fi_sysfile_type]#6 --> sb_pagefaults#2 --> &oi->ip_alloc_sem

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&oi->ip_alloc_sem);
                               lock(sb_pagefaults#2);
                               lock(&oi->ip_alloc_sem);
  lock(&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#6);

 *** DEADLOCK ***

3 locks held by syz.1.340/5274:
 #0: ffff88802221c460 (sb_writers#26){.+.+}-{0:0}, at: mnt_want_write+0x3b/0x80 fs/namespace.c:377
 #1: ffff888061a16d88 (&sb->s_type->i_mutex_key#35){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:789 [inline]
 #1: ffff888061a16d88 (&sb->s_type->i_mutex_key#35){+.+.}-{3:3}, at: do_truncate+0x208/0x300 fs/open.c:63
 #2: ffff888061a16a20 (&oi->ip_alloc_sem){++++}-{3:3}, at: ocfs2_truncate_file+0x345/0x14f0 fs/ocfs2/file.c:467

stack backtrace:
CPU: 1 PID: 5274 Comm: syz.1.340 Not tainted 5.15.167-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2d0 lib/dump_stack.c:106
 check_noncircular+0x2f8/0x3b0 kernel/locking/lockdep.c:2133
 check_prev_add kernel/locking/lockdep.c:3053 [inline]
 check_prevs_add kernel/locking/lockdep.c:3172 [inline]
 validate_chain+0x1649/0x5930 kernel/locking/lockdep.c:3788
 __lock_acquire+0x1295/0x1ff0 kernel/locking/lockdep.c:5012
 lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
 down_write+0x38/0x60 kernel/locking/rwsem.c:1551
 inode_lock include/linux/fs.h:789 [inline]
 ocfs2_remove_btree_range+0x733/0x18a0 fs/ocfs2/alloc.c:5735
 ocfs2_commit_truncate+0xcb3/0x2530 fs/ocfs2/alloc.c:7339
 ocfs2_truncate_file+0xd3d/0x14f0 fs/ocfs2/file.c:505
 ocfs2_setattr+0x165e/0x1c70 fs/ocfs2/file.c:1212
 notify_change+0xc6d/0xf50 fs/attr.c:505
 do_truncate+0x21c/0x300 fs/open.c:65
 handle_truncate fs/namei.c:3265 [inline]
 do_open fs/namei.c:3612 [inline]
 path_openat+0x28a3/0x2f20 fs/namei.c:3742
 do_filp_open+0x21c/0x460 fs/namei.c:3769
 do_sys_openat2+0x13b/0x4f0 fs/open.c:1253
 do_sys_open fs/open.c:1269 [inline]
 __do_sys_creat fs/open.c:1343 [inline]
 __se_sys_creat fs/open.c:1337 [inline]
 __x64_sys_creat+0x11f/0x160 fs/open.c:1337
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fc0bdab4ef9
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:00007fc0bbf0c038 EFLAGS: 00000246 ORIG_RAX: 0000000000000055
RAX: ffffffffffffffda RBX: 00007fc0bdc6d058 RCX: 00007fc0bdab4ef9
RDX: 0000000000000000 RSI: 000000000000000d RDI: 0000000020000240
RBP: 00007fc0bdb27b76 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000001 R14: 00007fc0bdc6d058 R15: 00007ffe04ba13d8
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/09/15 02:13 linux-5.15.y 3a5928702e71 08d8a733 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in ocfs2_remove_btree_range
* Struck through repros no longer work on HEAD.