syzbot


possible deadlock in ocfs2_write_begin_nolock

Status: upstream: reported on 2024/10/27 04:30
Reported-by: syzbot+1782a3a587bc53dc10cf@syzkaller.appspotmail.com
First crash: 37d, last: 26d
Similar bugs (2)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream possible deadlock in ocfs2_write_begin_nolock ocfs2 C 75 1d13h 82d 0/28 upstream: reported C repro on 2024/09/12 09:35
linux-6.1 possible deadlock in ocfs2_write_begin_nolock 9 7d01h 53d 0/3 upstream: reported on 2024/10/11 23:44

Sample crash report:
======================================================
WARNING: possible circular locking dependency detected
5.15.169-syzkaller #0 Not tainted
------------------------------------------------------
syz.8.3444/22574 is trying to acquire lock:
ffff88806409c650 (sb_internal#3){.+.+}-{0:0}, at: ocfs2_write_begin_inline fs/ocfs2/aops.c:1482 [inline]
ffff88806409c650 (sb_internal#3){.+.+}-{0:0}, at: ocfs2_try_to_write_inline_data fs/ocfs2/aops.c:1585 [inline]
ffff88806409c650 (sb_internal#3){.+.+}-{0:0}, at: ocfs2_write_begin_nolock+0x2242/0x4d20 fs/ocfs2/aops.c:1671

but task is already holding lock:
ffff8880747e3f60 (&ocfs2_file_ip_alloc_sem_key){++++}-{3:3}, at: ocfs2_write_begin+0x1cb/0x390 fs/ocfs2/aops.c:1903

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #4 (&ocfs2_file_ip_alloc_sem_key){++++}-{3:3}:
       lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
       down_write+0x38/0x60 kernel/locking/rwsem.c:1551
       ocfs2_try_remove_refcount_tree+0xb2/0x330 fs/ocfs2/refcounttree.c:932
       ocfs2_xattr_set+0xa4b/0x1930 fs/ocfs2/xattr.c:3674
       ocfs2_set_acl+0x4cb/0x570 fs/ocfs2/acl.c:254
       ocfs2_iop_set_acl+0x252/0x3c0 fs/ocfs2/acl.c:285
       set_posix_acl fs/posix_acl.c:947 [inline]
       posix_acl_xattr_set+0x33b/0x3a0 fs/posix_acl.c:966
       __vfs_removexattr+0x3ce/0x410 fs/xattr.c:470
       __vfs_removexattr_locked+0x1fe/0x410 fs/xattr.c:505
       vfs_removexattr+0xff/0x2a0 fs/xattr.c:527
       removexattr fs/xattr.c:857 [inline]
       path_removexattr+0x22a/0x320 fs/xattr.c:871
       __do_sys_lremovexattr fs/xattr.c:891 [inline]
       __se_sys_lremovexattr fs/xattr.c:888 [inline]
       __x64_sys_lremovexattr+0x59/0x70 fs/xattr.c:888
       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 (&oi->ip_xattr_sem){++++}-{3:3}:
       lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
       down_read+0x45/0x2e0 kernel/locking/rwsem.c:1498
       ocfs2_init_acl+0x398/0x930 fs/ocfs2/acl.c:365
       ocfs2_mknod+0x1e8f/0x2cd0 fs/ocfs2/namei.c:408
       ocfs2_create+0x194/0x430 fs/ocfs2/namei.c:672
       lookup_open fs/namei.c:3462 [inline]
       open_last_lookups fs/namei.c:3532 [inline]
       path_openat+0x130a/0x2f20 fs/namei.c:3739
       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_open fs/open.c:1277 [inline]
       __se_sys_open fs/open.c:1273 [inline]
       __x64_sys_open+0x221/0x270 fs/open.c:1273
       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 (jbd2_handle){++++}-{0:0}:
       lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
       start_this_handle+0x12e1/0x1570 fs/jbd2/transaction.c:464
       jbd2__journal_start+0x2d1/0x5c0 fs/jbd2/transaction.c:521
       jbd2_journal_start+0x25/0x30 fs/jbd2/transaction.c:560
       ocfs2_start_trans+0x3c2/0x6f0 fs/ocfs2/journal.c:354
       ocfs2_shutdown_local_alloc+0x214/0xa90 fs/ocfs2/localalloc.c:416
       ocfs2_dismount_volume+0x1db/0x8b0 fs/ocfs2/super.c:1882
       generic_shutdown_super+0x130/0x310 fs/super.c:475
       kill_block_super+0x7a/0xe0 fs/super.c:1427
       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

-> #1 (&journal->j_trans_barrier){.+.+}-{3:3}:
       lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
       down_read+0x45/0x2e0 kernel/locking/rwsem.c:1498
       ocfs2_start_trans+0x3b7/0x6f0 fs/ocfs2/journal.c:352
       ocfs2_shutdown_local_alloc+0x214/0xa90 fs/ocfs2/localalloc.c:416
       ocfs2_dismount_volume+0x1db/0x8b0 fs/ocfs2/super.c:1882
       generic_shutdown_super+0x130/0x310 fs/super.c:475
       kill_block_super+0x7a/0xe0 fs/super.c:1427
       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 (sb_internal#3){.+.+}-{0:0}:
       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
       percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
       __sb_start_write include/linux/fs.h:1813 [inline]
       sb_start_intwrite include/linux/fs.h:1930 [inline]
       ocfs2_start_trans+0x2b2/0x6f0 fs/ocfs2/journal.c:350
       ocfs2_write_begin_inline fs/ocfs2/aops.c:1482 [inline]
       ocfs2_try_to_write_inline_data fs/ocfs2/aops.c:1585 [inline]
       ocfs2_write_begin_nolock+0x2242/0x4d20 fs/ocfs2/aops.c:1671
       ocfs2_write_begin+0x1fd/0x390 fs/ocfs2/aops.c:1905
       generic_perform_write+0x2bf/0x5b0 mm/filemap.c:3785
       __generic_file_write_iter+0x243/0x4f0 mm/filemap.c:3912
       ocfs2_file_write_iter+0x17d5/0x1fa0 fs/ocfs2/file.c:2459
       call_write_iter include/linux/fs.h:2174 [inline]
       new_sync_write fs/read_write.c:507 [inline]
       vfs_write+0xacd/0xe50 fs/read_write.c:594
       ksys_pwrite64 fs/read_write.c:701 [inline]
       __do_sys_pwrite64 fs/read_write.c:711 [inline]
       __se_sys_pwrite64 fs/read_write.c:708 [inline]
       __x64_sys_pwrite64+0x1a9/0x230 fs/read_write.c:708
       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:
  sb_internal#3 --> &oi->ip_xattr_sem --> &ocfs2_file_ip_alloc_sem_key

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&ocfs2_file_ip_alloc_sem_key);
                               lock(&oi->ip_xattr_sem);
                               lock(&ocfs2_file_ip_alloc_sem_key);
  lock(sb_internal#3);

 *** DEADLOCK ***

3 locks held by syz.8.3444/22574:
 #0: ffff88806409c460 (sb_writers#24){.+.+}-{0:0}, at: vfs_write+0x29a/0xe50 fs/read_write.c:590
 #1: ffff8880747e42c8 (&sb->s_type->i_mutex_key#29){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:789 [inline]
 #1: ffff8880747e42c8 (&sb->s_type->i_mutex_key#29){+.+.}-{3:3}, at: ocfs2_file_write_iter+0x446/0x1fa0 fs/ocfs2/file.c:2391
 #2: ffff8880747e3f60 (&ocfs2_file_ip_alloc_sem_key){++++}-{3:3}, at: ocfs2_write_begin+0x1cb/0x390 fs/ocfs2/aops.c:1903

stack backtrace:
CPU: 0 PID: 22574 Comm: syz.8.3444 Not tainted 5.15.169-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
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
 percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
 __sb_start_write include/linux/fs.h:1813 [inline]
 sb_start_intwrite include/linux/fs.h:1930 [inline]
 ocfs2_start_trans+0x2b2/0x6f0 fs/ocfs2/journal.c:350
 ocfs2_write_begin_inline fs/ocfs2/aops.c:1482 [inline]
 ocfs2_try_to_write_inline_data fs/ocfs2/aops.c:1585 [inline]
 ocfs2_write_begin_nolock+0x2242/0x4d20 fs/ocfs2/aops.c:1671
 ocfs2_write_begin+0x1fd/0x390 fs/ocfs2/aops.c:1905
 generic_perform_write+0x2bf/0x5b0 mm/filemap.c:3785
 __generic_file_write_iter+0x243/0x4f0 mm/filemap.c:3912
 ocfs2_file_write_iter+0x17d5/0x1fa0 fs/ocfs2/file.c:2459
 call_write_iter include/linux/fs.h:2174 [inline]
 new_sync_write fs/read_write.c:507 [inline]
 vfs_write+0xacd/0xe50 fs/read_write.c:594
 ksys_pwrite64 fs/read_write.c:701 [inline]
 __do_sys_pwrite64 fs/read_write.c:711 [inline]
 __se_sys_pwrite64 fs/read_write.c:708 [inline]
 __x64_sys_pwrite64+0x1a9/0x230 fs/read_write.c:708
 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: 0033:0x7f4ce1442719
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:00007f4cdf899038 EFLAGS: 00000246 ORIG_RAX: 0000000000000012
RAX: ffffffffffffffda RBX: 00007f4ce15fa058 RCX: 00007f4ce1442719
RDX: 0000000000000001 RSI: 0000000020000280 RDI: 0000000000000004
RBP: 00007f4ce14b532e R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000001 R14: 00007f4ce15fa058 R15: 00007fff2449ffd8
 </TASK>

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/10/27 04:29 linux-5.15.y 74cdd62cb470 65e8686b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in ocfs2_write_begin_nolock
2024/11/07 09:35 linux-5.15.y 72244eab0dad df3dc63b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 possible deadlock in ocfs2_write_begin_nolock
* Struck through repros no longer work on HEAD.