syzbot
possible deadlock in ocfs2_reflink
Status:
upstream: reported on 2026/07/31 10:33
Reported-by: syzbot+4e92af9ecc77271379ce@syzkaller.appspotmail.com
First crash: 5d01h, last: 13h10m
Sample crash report:
loop2: detected capacity change from 0 to 262144
JBD2: Ignoring recovery information on journal
ocfs2: Mounting device (7,2) on (node local, slot 0) with ordered data mode.
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.2.63/4487 is trying to acquire lock:
ffff888062683f60 (&oi->ip_alloc_sem){+.+.}-{3:3}, at: ocfs2_reflink+0x4cb/0x920 fs/ocfs2/refcounttree.c:4304
but task is already holding lock:
ffff888062683ff8 (&oi->ip_xattr_sem){++++}-{3:3}, at: ocfs2_reflink+0x4bc/0x920 fs/ocfs2/refcounttree.c:4303
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #5 (&oi->ip_xattr_sem){++++}-{3:3}:
down_read+0x44/0x2e0 kernel/locking/rwsem.c:1498
ocfs2_init_acl+0x307/0x770 fs/ocfs2/acl.c:365
ocfs2_mknod+0x15de/0x2510 fs/ocfs2/namei.c:410
ocfs2_create+0x192/0x420 fs/ocfs2/namei.c:674
vfs_create+0x2db/0x460 fs/namei.c:3170
do_mknodat+0x49e/0x630 fs/namei.c:4002
__do_sys_mknodat fs/namei.c:4030 [inline]
__se_sys_mknodat fs/namei.c:4027 [inline]
__x64_sys_mknodat+0xa5/0xc0 fs/namei.c:4027
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
-> #4 (&journal->j_trans_barrier){.+.+}-{3:3}:
down_read+0x44/0x2e0 kernel/locking/rwsem.c:1498
ocfs2_start_trans+0x3a6/0x6f0 fs/ocfs2/journal.c:374
ocfs2_block_group_alloc fs/ocfs2/suballoc.c:703 [inline]
ocfs2_reserve_suballoc_bits+0x7a3/0x44b0 fs/ocfs2/suballoc.c:850
ocfs2_reserve_new_metadata_blocks+0x412/0x9a0 fs/ocfs2/suballoc.c:1000
ocfs2_expand_inline_dir fs/ocfs2/dir.c:2838 [inline]
ocfs2_extend_dir+0xd4a/0x4b90 fs/ocfs2/dir.c:3200
ocfs2_prepare_dir_for_insert+0x2efd/0x52b0 fs/ocfs2/dir.c:4321
ocfs2_mknod+0x876/0x2510 fs/ocfs2/namei.c:294
ocfs2_create+0x192/0x420 fs/ocfs2/namei.c:674
vfs_create+0x2db/0x460 fs/namei.c:3170
do_mknodat+0x49e/0x630 fs/namei.c:4002
__do_sys_mknodat fs/namei.c:4030 [inline]
__se_sys_mknodat fs/namei.c:4027 [inline]
__x64_sys_mknodat+0xa5/0xc0 fs/namei.c:4027
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
-> #3 (sb_internal#3){.+.+}-{0:0}:
percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
__sb_start_write include/linux/fs.h:1811 [inline]
sb_start_intwrite include/linux/fs.h:1928 [inline]
ocfs2_start_trans+0x2a7/0x6f0 fs/ocfs2/journal.c:372
ocfs2_block_group_alloc fs/ocfs2/suballoc.c:703 [inline]
ocfs2_reserve_suballoc_bits+0x7a3/0x44b0 fs/ocfs2/suballoc.c:850
ocfs2_reserve_new_metadata_blocks+0x412/0x9a0 fs/ocfs2/suballoc.c:1000
ocfs2_expand_inline_dir fs/ocfs2/dir.c:2838 [inline]
ocfs2_extend_dir+0xd4a/0x4b90 fs/ocfs2/dir.c:3200
ocfs2_prepare_dir_for_insert+0x2efd/0x52b0 fs/ocfs2/dir.c:4321
ocfs2_mknod+0x876/0x2510 fs/ocfs2/namei.c:294
ocfs2_create+0x192/0x420 fs/ocfs2/namei.c:674
vfs_create+0x2db/0x460 fs/namei.c:3170
do_mknodat+0x49e/0x630 fs/namei.c:4002
__do_sys_mknodat fs/namei.c:4030 [inline]
__se_sys_mknodat fs/namei.c:4027 [inline]
__x64_sys_mknodat+0xa5/0xc0 fs/namei.c:4027
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
-> #2 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#3){+.+.}-{3:3}:
down_write+0x38/0x60 kernel/locking/rwsem.c:1551
inode_lock include/linux/fs.h:787 [inline]
ocfs2_reserve_suballoc_bits+0x16d/0x44b0 fs/ocfs2/suballoc.c:804
ocfs2_reserve_cluster_bitmap_bits fs/ocfs2/suballoc.c:1150 [inline]
ocfs2_reserve_clusters_with_limit+0x3b9/0xc10 fs/ocfs2/suballoc.c:1195
ocfs2_block_group_alloc fs/ocfs2/suballoc.c:692 [inline]
ocfs2_reserve_suballoc_bits+0x781/0x44b0 fs/ocfs2/suballoc.c:850
ocfs2_reserve_new_metadata_blocks+0x412/0x9a0 fs/ocfs2/suballoc.c:1000
ocfs2_expand_inline_dir fs/ocfs2/dir.c:2838 [inline]
ocfs2_extend_dir+0xd4a/0x4b90 fs/ocfs2/dir.c:3200
ocfs2_prepare_dir_for_insert+0x2efd/0x52b0 fs/ocfs2/dir.c:4321
ocfs2_mknod+0x876/0x2510 fs/ocfs2/namei.c:294
ocfs2_create+0x192/0x420 fs/ocfs2/namei.c:674
vfs_create+0x2db/0x460 fs/namei.c:3170
do_mknodat+0x49e/0x630 fs/namei.c:4002
__do_sys_mknodat fs/namei.c:4030 [inline]
__se_sys_mknodat fs/namei.c:4027 [inline]
__x64_sys_mknodat+0xa5/0xc0 fs/namei.c:4027
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
-> #1 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#2){+.+.}-{3:3}:
down_write+0x38/0x60 kernel/locking/rwsem.c:1551
inode_lock include/linux/fs.h:787 [inline]
ocfs2_reserve_suballoc_bits+0x16d/0x44b0 fs/ocfs2/suballoc.c:804
ocfs2_reserve_new_metadata_blocks+0x412/0x9a0 fs/ocfs2/suballoc.c:1000
ocfs2_reserve_new_metadata fs/ocfs2/suballoc.c:1043 [inline]
ocfs2_lock_allocators+0x28f/0x5f0 fs/ocfs2/suballoc.c:2690
ocfs2_extend_allocation+0x3fe/0x1830 fs/ocfs2/file.c:588
ocfs2_allocate_unwritten_extents+0x311/0x830 fs/ocfs2/file.c:1499
__ocfs2_change_file_space+0x7dc/0xf60 fs/ocfs2/file.c:2026
ocfs2_fallocate+0x1ee/0x240 fs/ocfs2/file.c:2141
vfs_fallocate+0x57e/0x6f0 fs/open.c:308
ksys_fallocate fs/open.c:331 [inline]
__do_sys_fallocate fs/open.c:339 [inline]
__se_sys_fallocate fs/open.c:337 [inline]
__x64_sys_fallocate+0xbd/0x100 fs/open.c:337
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
-> #0 (&oi->ip_alloc_sem){+.+.}-{3:3}:
check_prev_add kernel/locking/lockdep.c:3053 [inline]
check_prevs_add kernel/locking/lockdep.c:3172 [inline]
validate_chain kernel/locking/lockdep.c:3788 [inline]
__lock_acquire+0x2c66/0x7b50 kernel/locking/lockdep.c:5012
lock_acquire+0x19e/0x400 kernel/locking/lockdep.c:5623
down_write+0x38/0x60 kernel/locking/rwsem.c:1551
ocfs2_reflink+0x4cb/0x920 fs/ocfs2/refcounttree.c:4304
ocfs2_vfs_reflink+0x333/0x450 fs/ocfs2/refcounttree.c:4431
ocfs2_reflink_ioctl+0x39c/0x440 fs/ocfs2/refcounttree.c:4471
ocfs2_ioctl+0x586/0x7a0 fs/ocfs2/ioctl.c:913
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:874 [inline]
__se_sys_ioctl+0xfa/0x170 fs/ioctl.c:860
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
other info that might help us debug this:
Chain exists of:
&oi->ip_alloc_sem --> &journal->j_trans_barrier --> &oi->ip_xattr_sem
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&oi->ip_xattr_sem);
lock(&journal->j_trans_barrier);
lock(&oi->ip_xattr_sem);
lock(&oi->ip_alloc_sem);
*** DEADLOCK ***
4 locks held by syz.2.63/4487:
#0: ffff88801f100460 (sb_writers#17){.+.+}-{0:0}, at: mnt_want_write+0x3d/0x90 fs/namespace.c:386
#1: ffff888062683488 (&sb->s_type->i_mutex_key#23/1){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:822 [inline]
#1: ffff888062683488 (&sb->s_type->i_mutex_key#23/1){+.+.}-{3:3}, at: filename_create+0x20b/0x450 fs/namei.c:3843
#2: ffff8880626842c8 (&sb->s_type->i_mutex_key#23){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:787 [inline]
#2: ffff8880626842c8 (&sb->s_type->i_mutex_key#23){+.+.}-{3:3}, at: ocfs2_vfs_reflink+0x2f3/0x450 fs/ocfs2/refcounttree.c:4428
#3: ffff888062683ff8 (&oi->ip_xattr_sem){++++}-{3:3}, at: ocfs2_reflink+0x4bc/0x920 fs/ocfs2/refcounttree.c:4303
stack backtrace:
CPU: 1 PID: 4487 Comm: syz.2.63 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
<TASK>
dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
check_noncircular+0x296/0x330 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 kernel/locking/lockdep.c:3788 [inline]
__lock_acquire+0x2c66/0x7b50 kernel/locking/lockdep.c:5012
lock_acquire+0x19e/0x400 kernel/locking/lockdep.c:5623
down_write+0x38/0x60 kernel/locking/rwsem.c:1551
ocfs2_reflink+0x4cb/0x920 fs/ocfs2/refcounttree.c:4304
ocfs2_vfs_reflink+0x333/0x450 fs/ocfs2/refcounttree.c:4431
ocfs2_reflink_ioctl+0x39c/0x440 fs/ocfs2/refcounttree.c:4471
ocfs2_ioctl+0x586/0x7a0 fs/ocfs2/ioctl.c:913
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:874 [inline]
__se_sys_ioctl+0xfa/0x170 fs/ioctl.c:860
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f233291a019
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f2330b72028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f2332ba1fa0 RCX: 00007f233291a019
RDX: 0000200000000200 RSI: 0000000040186f04 RDI: 0000000000000004
RBP: 00007f23329b100c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f2332ba2038 R14: 00007f2332ba1fa0 R15: 00007ffd04e663d8
</TASK>
Struck through repros no longer work on HEAD.