syzbot


possible deadlock in ocfs2_lock_refcount_tree

Status: upstream: reported on 2024/09/06 16:20
Subsystems: ocfs2
[Documentation on labels]
Reported-by: syzbot+285cfeaeb4ba53a373aa@syzkaller.appspotmail.com
First crash: 32d, last: 11d
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [ocfs2?] possible deadlock in ocfs2_lock_refcount_tree 0 (1) 2024/09/06 16:20
Similar bugs (1)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 possible deadlock in ocfs2_lock_refcount_tree 3 4d14h 20d 0/3 upstream: reported on 2024/09/14 13:53

Sample crash report:
loop2: detected capacity change from 0 to 32768
ocfs2: Mounting device (7,2) on (node local, slot 0) with ordered data mode.
======================================================
WARNING: possible circular locking dependency detected
6.11.0-syzkaller-08829-gaf9c191ac2a0 #0 Not tainted
------------------------------------------------------
syz.2.47/5602 is trying to acquire lock:
ffff88805c27e898 (&new->rf_sem){+.+.}-{3:3}, at: __ocfs2_lock_refcount_tree fs/ocfs2/refcounttree.c:427 [inline]
ffff88805c27e898 (&new->rf_sem){+.+.}-{3:3}, at: ocfs2_lock_refcount_tree+0x1fe/0xa70 fs/ocfs2/refcounttree.c:462

but task is already holding lock:
ffff88805adda2e0 (&ocfs2_file_ip_alloc_sem_key){++++}-{3:3}, at: ocfs2_truncate_file+0x372/0x1560 fs/ocfs2/file.c:471

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (&ocfs2_file_ip_alloc_sem_key){++++}-{3:3}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5822
       down_read+0xb1/0xa40 kernel/locking/rwsem.c:1526
       ocfs2_read_virt_blocks+0x2ca/0xa50 fs/ocfs2/extent_map.c:976
       ocfs2_read_dir_block fs/ocfs2/dir.c:508 [inline]
       ocfs2_find_entry_el fs/ocfs2/dir.c:715 [inline]
       ocfs2_find_entry+0x43b/0x2780 fs/ocfs2/dir.c:1080
       ocfs2_find_files_on_disk+0xff/0x360 fs/ocfs2/dir.c:1981
       ocfs2_lookup_ino_from_name+0xb1/0x1e0 fs/ocfs2/dir.c:2003
       _ocfs2_get_system_file_inode fs/ocfs2/sysfile.c:136 [inline]
       ocfs2_get_system_file_inode+0x305/0x7b0 fs/ocfs2/sysfile.c:112
       ocfs2_init_global_system_inodes+0x32c/0x730 fs/ocfs2/super.c:457
       ocfs2_initialize_super fs/ocfs2/super.c:2250 [inline]
       ocfs2_fill_super+0x2f47/0x5750 fs/ocfs2/super.c:994
       mount_bdev+0x20c/0x2d0 fs/super.c:1679
       legacy_get_tree+0xf0/0x190 fs/fs_context.c:662
       vfs_get_tree+0x92/0x2b0 fs/super.c:1800
       do_new_mount+0x2be/0xb40 fs/namespace.c:3507
       do_mount fs/namespace.c:3847 [inline]
       __do_sys_mount fs/namespace.c:4055 [inline]
       __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:4032
       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

-> #1 (&osb->system_file_mutex){+.+.}-{3:3}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5822
       __mutex_lock_common kernel/locking/mutex.c:608 [inline]
       __mutex_lock+0x136/0xd70 kernel/locking/mutex.c:752
       ocfs2_get_system_file_inode+0x18f/0x7b0 fs/ocfs2/sysfile.c:101
       ocfs2_reserve_suballoc_bits+0x16f/0x4eb0 fs/ocfs2/suballoc.c:780
       ocfs2_reserve_new_metadata_blocks+0x41c/0x9c0 fs/ocfs2/suballoc.c:982
       ocfs2_add_refcount_flag+0x4a0/0x1150 fs/ocfs2/refcounttree.c:3676
       ocfs2_reflink_remap_extent fs/ocfs2/refcounttree.c:4535 [inline]
       ocfs2_reflink_remap_blocks+0xe58/0x1f30 fs/ocfs2/refcounttree.c:4662
       ocfs2_remap_file_range+0x5fa/0x8d0 fs/ocfs2/file.c:2725
       vfs_copy_file_range+0xc09/0x1510 fs/read_write.c:1615
       __do_sys_copy_file_range fs/read_write.c:1705 [inline]
       __se_sys_copy_file_range+0x3f2/0x5d0 fs/read_write.c:1668
       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

-> #0 (&new->rf_sem){+.+.}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3158 [inline]
       check_prevs_add kernel/locking/lockdep.c:3277 [inline]
       validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3901
       __lock_acquire+0x1384/0x2050 kernel/locking/lockdep.c:5199
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5822
       down_write+0x99/0x220 kernel/locking/rwsem.c:1579
       __ocfs2_lock_refcount_tree fs/ocfs2/refcounttree.c:427 [inline]
       ocfs2_lock_refcount_tree+0x1fe/0xa70 fs/ocfs2/refcounttree.c:462
       ocfs2_commit_truncate+0xc78/0x2560 fs/ocfs2/alloc.c:7345
       ocfs2_truncate_file+0xd0e/0x1560 fs/ocfs2/file.c:509
       ocfs2_setattr+0x1217/0x1f50 fs/ocfs2/file.c:1209
       notify_change+0xbcc/0xe90 fs/attr.c:503
       do_truncate+0x220/0x310 fs/open.c:65
       handle_truncate fs/namei.c:3395 [inline]
       do_open fs/namei.c:3778 [inline]
       path_openat+0x2e1e/0x3590 fs/namei.c:3933
       do_filp_open+0x235/0x490 fs/namei.c:3960
       do_sys_openat2+0x13e/0x1d0 fs/open.c:1415
       do_sys_open fs/open.c:1430 [inline]
       __do_sys_creat fs/open.c:1506 [inline]
       __se_sys_creat fs/open.c:1500 [inline]
       __x64_sys_creat+0x123/0x170 fs/open.c:1500
       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

other info that might help us debug this:

Chain exists of:
  &new->rf_sem --> &osb->system_file_mutex --> &ocfs2_file_ip_alloc_sem_key

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&ocfs2_file_ip_alloc_sem_key);
                               lock(&osb->system_file_mutex);
                               lock(&ocfs2_file_ip_alloc_sem_key);
  lock(&new->rf_sem);

 *** DEADLOCK ***

3 locks held by syz.2.47/5602:
 #0: ffff88805c2cc420 (sb_writers#17){.+.+}-{0:0}, at: mnt_want_write+0x3f/0x90 fs/namespace.c:515
 #1: ffff88805adda640 (&sb->s_type->i_mutex_key#24){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:815 [inline]
 #1: ffff88805adda640 (&sb->s_type->i_mutex_key#24){+.+.}-{3:3}, at: do_truncate+0x20c/0x310 fs/open.c:63
 #2: ffff88805adda2e0 (&ocfs2_file_ip_alloc_sem_key){++++}-{3:3}, at: ocfs2_truncate_file+0x372/0x1560 fs/ocfs2/file.c:471

stack backtrace:
CPU: 0 UID: 0 PID: 5602 Comm: syz.2.47 Not tainted 6.11.0-syzkaller-08829-gaf9c191ac2a0 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 print_circular_bug+0x13a/0x1b0 kernel/locking/lockdep.c:2074
 check_noncircular+0x36a/0x4a0 kernel/locking/lockdep.c:2203
 check_prev_add kernel/locking/lockdep.c:3158 [inline]
 check_prevs_add kernel/locking/lockdep.c:3277 [inline]
 validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3901
 __lock_acquire+0x1384/0x2050 kernel/locking/lockdep.c:5199
 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5822
 down_write+0x99/0x220 kernel/locking/rwsem.c:1579
 __ocfs2_lock_refcount_tree fs/ocfs2/refcounttree.c:427 [inline]
 ocfs2_lock_refcount_tree+0x1fe/0xa70 fs/ocfs2/refcounttree.c:462
 ocfs2_commit_truncate+0xc78/0x2560 fs/ocfs2/alloc.c:7345
 ocfs2_truncate_file+0xd0e/0x1560 fs/ocfs2/file.c:509
 ocfs2_setattr+0x1217/0x1f50 fs/ocfs2/file.c:1209
 notify_change+0xbcc/0xe90 fs/attr.c:503
 do_truncate+0x220/0x310 fs/open.c:65
 handle_truncate fs/namei.c:3395 [inline]
 do_open fs/namei.c:3778 [inline]
 path_openat+0x2e1e/0x3590 fs/namei.c:3933
 do_filp_open+0x235/0x490 fs/namei.c:3960
 do_sys_openat2+0x13e/0x1d0 fs/open.c:1415
 do_sys_open fs/open.c:1430 [inline]
 __do_sys_creat fs/open.c:1506 [inline]
 __se_sys_creat fs/open.c:1500 [inline]
 __x64_sys_creat+0x123/0x170 fs/open.c:1500
 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: 0033:0x7fd55537def9
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:00007fd556233038 EFLAGS: 00000246 ORIG_RAX: 0000000000000055
RAX: ffffffffffffffda RBX: 00007fd555535f80 RCX: 00007fd55537def9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000020000040
RBP: 00007fd5553f0b76 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fd555535f80 R15: 00007ffcce7e97a8
 </TASK>
ocfs2: Unmounting device (7,2) on (node local)

Crashes (5):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/09/23 02:26 upstream af9c191ac2a0 6f888b75 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root possible deadlock in ocfs2_lock_refcount_tree
2024/09/22 06:26 upstream 88264981f208 6f888b75 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root possible deadlock in ocfs2_lock_refcount_tree
2024/09/22 05:20 upstream 88264981f208 6f888b75 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root possible deadlock in ocfs2_lock_refcount_tree
2024/09/14 03:14 upstream e936e7d4a83b 158f4851 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root possible deadlock in ocfs2_lock_refcount_tree
2024/09/02 16:16 upstream 67784a74e258 1eda0d14 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root possible deadlock in ocfs2_lock_refcount_tree
* Struck through repros no longer work on HEAD.