possible deadlock in bd_register_pending_holders

Status: auto-obsoleted due to no activity on 2024/01/12 20:03
Reported-by: syzbot+ad62b217aacd3fc375b2@syzkaller.appspotmail.com
First crash: 1175d, last: 1043d
▶ ▼ Similar bugs (4)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream possible deadlock in bd_register_pending_holders block 4 3 1744d 1798d 20/29 fixed on 2021/11/10 00:50
linux-5.15 possible deadlock in bd_register_pending_holders (3) 4 21 12d 417d 0/3 upstream: reported on 2025/06/22 16:07
upstream possible deadlock in bd_register_pending_holders (2) block 4 4 1706d 1723d 0/29 closed as dup on 2021/11/24 22:11
linux-5.15 possible deadlock in bd_register_pending_holders (2) 4 20 518d 850d 0/3 auto-obsoleted due to no activity on 2025/06/20 22:13

Sample crash report:
======================================================
WARNING: possible circular locking dependency detected
5.15.133-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.4/24988 is trying to acquire lock:
ffff88801cbe2918 (&disk->open_mutex){+.+.}-{3:3}, at: bd_register_pending_holders+0x33/0x320 block/holder.c:161

but task is already holding lock:
ffffffff8ceeb468 (major_names_lock){+.+.}-{3:3}, at: blk_request_module+0x2f/0x1a0 block/genhd.c:681

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #8 (major_names_lock){+.+.}-{3:3}:
       lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5622
       __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
       blk_request_module+0x2f/0x1a0 block/genhd.c:681
       blkdev_get_no_open+0x39/0x190 block/bdev.c:740
       blkdev_get_by_dev+0x89/0xa50 block/bdev.c:804
       swsusp_check+0xb1/0x2c0 kernel/power/swap.c:1526
       software_resume+0xc6/0x3c0 kernel/power/hibernate.c:977
       resume_store+0xe3/0x130 kernel/power/hibernate.c:1179
       kernfs_fop_write_iter+0x3a2/0x4f0 fs/kernfs/file.c:296
       call_write_iter include/linux/fs.h:2103 [inline]
       new_sync_write fs/read_write.c:507 [inline]
       vfs_write+0xacf/0xe50 fs/read_write.c:594
       ksys_write+0x1a2/0x2c0 fs/read_write.c:647
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x61/0xcb

-> #7 (system_transition_mutex/1){+.+.}-{3:3}:
       lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5622
       __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
       software_resume+0x7c/0x3c0 kernel/power/hibernate.c:932
       resume_store+0xe3/0x130 kernel/power/hibernate.c:1179
       kernfs_fop_write_iter+0x3a2/0x4f0 fs/kernfs/file.c:296
       call_write_iter include/linux/fs.h:2103 [inline]
       new_sync_write fs/read_write.c:507 [inline]
       vfs_write+0xacf/0xe50 fs/read_write.c:594
       ksys_write+0x1a2/0x2c0 fs/read_write.c:647
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x61/0xcb

-> #6 (&of->mutex){+.+.}-{3:3}:
       lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5622
       __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
       kernfs_seq_start+0x50/0x3b0 fs/kernfs/file.c:112
       seq_read_iter+0x3d0/0xd10 fs/seq_file.c:225
       call_read_iter include/linux/fs.h:2097 [inline]
       new_sync_read fs/read_write.c:404 [inline]
       vfs_read+0xa9f/0xe10 fs/read_write.c:485
       ksys_read+0x1a2/0x2c0 fs/read_write.c:623
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x61/0xcb

-> #5 (&p->lock){+.+.}-{3:3}:
       lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5622
       __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
       seq_read_iter+0xae/0xd10 fs/seq_file.c:182
       proc_reg_read_iter+0x1b7/0x280 fs/proc/inode.c:300
       call_read_iter include/linux/fs.h:2097 [inline]
       generic_file_splice_read+0x4ad/0x790 fs/splice.c:311
       do_splice_to fs/splice.c:796 [inline]
       splice_direct_to_actor+0x448/0xc10 fs/splice.c:870
       do_splice_direct+0x285/0x3d0 fs/splice.c:979
       do_sendfile+0x625/0xff0 fs/read_write.c:1249
       __do_sys_sendfile64 fs/read_write.c:1317 [inline]
       __se_sys_sendfile64+0x178/0x1e0 fs/read_write.c:1303
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x61/0xcb

-> #4 (sb_writers#3){.+.+}-{0:0}:
       lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5622
       percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
       __sb_start_write include/linux/fs.h:1742 [inline]
       sb_start_write include/linux/fs.h:1812 [inline]
       file_start_write include/linux/fs.h:2966 [inline]
       lo_write_bvec+0x1a3/0x740 drivers/block/loop.c:315
       lo_write_simple drivers/block/loop.c:338 [inline]
       do_req_filebacked drivers/block/loop.c:656 [inline]
       loop_handle_cmd drivers/block/loop.c:2234 [inline]
       loop_process_work+0x2309/0x2af0 drivers/block/loop.c:2274
       process_one_work+0x8a1/0x10c0 kernel/workqueue.c:2310
       worker_thread+0xaca/0x1280 kernel/workqueue.c:2457
       kthread+0x3f6/0x4f0 kernel/kthread.c:319
       ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298

-> #3 ((work_completion)(&worker->work)){+.+.}-{0:0}:
       lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5622
       process_one_work+0x7f1/0x10c0 kernel/workqueue.c:2286
       worker_thread+0xaca/0x1280 kernel/workqueue.c:2457
       kthread+0x3f6/0x4f0 kernel/kthread.c:319
       ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298

-> #2 ((wq_completion)loop5){+.+.}-{0:0}:
       lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5622
       flush_workqueue+0x170/0x1610 kernel/workqueue.c:2830
       drain_workqueue+0xc5/0x390 kernel/workqueue.c:2995
       destroy_workqueue+0x7b/0xae0 kernel/workqueue.c:4430
       __loop_clr_fd+0x241/0xbe0 drivers/block/loop.c:1383
       blkdev_put_whole block/bdev.c:692 [inline]
       blkdev_put+0x455/0x790 block/bdev.c:954
       btrfs_close_bdev fs/btrfs/volumes.c:1153 [inline]
       btrfs_close_one_device fs/btrfs/volumes.c:1174 [inline]
       close_fs_devices+0x45e/0x8e0 fs/btrfs/volumes.c:1217
       btrfs_close_devices+0xc4/0x5c0 fs/btrfs/volumes.c:1232
       close_ctree+0x731/0x886 fs/btrfs/disk-io.c:4506
       generic_shutdown_super+0x136/0x2c0 fs/super.c:475
       kill_anon_super+0x37/0x60 fs/super.c:1076
       btrfs_kill_super+0x3d/0x50 fs/btrfs/super.c:2391
       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:164
       tracehook_notify_resume include/linux/tracehook.h:189 [inline]
       exit_to_user_mode_loop+0x106/0x130 kernel/entry/common.c:175
       exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:208
       __syscall_exit_to_user_mode_work kernel/entry/common.c:290 [inline]
       syscall_exit_to_user_mode+0x5d/0x250 kernel/entry/common.c:301
       do_syscall_64+0x49/0xb0 arch/x86/entry/common.c:86
       entry_SYSCALL_64_after_hwframe+0x61/0xcb

-> #1 (&lo->lo_mutex){+.+.}-{3:3}:
       lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5622
       __mutex_lock_common+0x1da/0x25a0 kernel/locking/mutex.c:596
       __mutex_lock kernel/locking/mutex.c:729 [inline]
       mutex_lock_killable_nested+0x17/0x20 kernel/locking/mutex.c:758
       lo_open+0x68/0x100 drivers/block/loop.c:2055
       blkdev_get_whole+0x94/0x390 block/bdev.c:669
       blkdev_get_by_dev+0x2bc/0xa50 block/bdev.c:824
       blkdev_open+0x138/0x2d0 block/fops.c:463
       do_dentry_open+0x807/0xfb0 fs/open.c:826
       do_open fs/namei.c:3538 [inline]
       path_openat+0x2702/0x2f20 fs/namei.c:3672
       do_filp_open+0x21c/0x460 fs/namei.c:3699
       do_sys_openat2+0x13b/0x500 fs/open.c:1211
       do_sys_open fs/open.c:1227 [inline]
       __do_sys_openat fs/open.c:1243 [inline]
       __se_sys_openat fs/open.c:1238 [inline]
       __x64_sys_openat+0x243/0x290 fs/open.c:1238
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x61/0xcb

-> #0 (&disk->open_mutex){+.+.}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3053 [inline]
       check_prevs_add kernel/locking/lockdep.c:3172 [inline]
       validate_chain+0x1646/0x58b0 kernel/locking/lockdep.c:3787
       __lock_acquire+0x1295/0x1ff0 kernel/locking/lockdep.c:5011
       lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5622
       __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
       bd_register_pending_holders+0x33/0x320 block/holder.c:161
       device_add_disk+0x526/0xc50 block/genhd.c:484
       add_disk include/linux/genhd.h:203 [inline]
       brd_alloc+0x4e6/0x720 drivers/block/brd.c:425
       blk_request_module+0x181/0x1a0 block/genhd.c:684
       blkdev_get_no_open+0x39/0x190 block/bdev.c:740
       blkdev_get_by_dev+0x89/0xa50 block/bdev.c:804
       swsusp_check+0xb1/0x2c0 kernel/power/swap.c:1526
       software_resume+0xc6/0x3c0 kernel/power/hibernate.c:977
       resume_store+0xe3/0x130 kernel/power/hibernate.c:1179
       kernfs_fop_write_iter+0x3a2/0x4f0 fs/kernfs/file.c:296
       call_write_iter include/linux/fs.h:2103 [inline]
       new_sync_write fs/read_write.c:507 [inline]
       vfs_write+0xacf/0xe50 fs/read_write.c:594
       ksys_write+0x1a2/0x2c0 fs/read_write.c:647
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x61/0xcb

other info that might help us debug this:

Chain exists of:
  &disk->open_mutex --> system_transition_mutex/1 --> major_names_lock

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(major_names_lock);
                               lock(system_transition_mutex/1);
                               lock(major_names_lock);
  lock(&disk->open_mutex);

 *** DEADLOCK ***

6 locks held by syz-executor.4/24988:
 #0: ffff88808203eff0 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2cb/0x380 fs/file.c:1088
 #1: ffff88807f4f6460 (sb_writers#8){.+.+}-{0:0}, at: vfs_write+0x29a/0xe50 fs/read_write.c:590
 #2: ffff888075d9c888 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1e7/0x4f0 fs/kernfs/file.c:287
 #3: ffff8881407bfbd0 (kn->active#748){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x20b/0x4f0 fs/kernfs/file.c:288
 #4: ffffffff8c7d7bc8 (system_transition_mutex/1){+.+.}-{3:3}, at: software_resume+0x7c/0x3c0 kernel/power/hibernate.c:932
 #5: ffffffff8ceeb468 (major_names_lock){+.+.}-{3:3}, at: blk_request_module+0x2f/0x1a0 block/genhd.c:681

stack backtrace:
CPU: 0 PID: 24988 Comm: syz-executor.4 Not tainted 5.15.133-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/06/2023
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2cb 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+0x1646/0x58b0 kernel/locking/lockdep.c:3787
 __lock_acquire+0x1295/0x1ff0 kernel/locking/lockdep.c:5011
 lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5622
 __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
 bd_register_pending_holders+0x33/0x320 block/holder.c:161
 device_add_disk+0x526/0xc50 block/genhd.c:484
 add_disk include/linux/genhd.h:203 [inline]
 brd_alloc+0x4e6/0x720 drivers/block/brd.c:425
 blk_request_module+0x181/0x1a0 block/genhd.c:684
 blkdev_get_no_open+0x39/0x190 block/bdev.c:740
 blkdev_get_by_dev+0x89/0xa50 block/bdev.c:804
 swsusp_check+0xb1/0x2c0 kernel/power/swap.c:1526
 software_resume+0xc6/0x3c0 kernel/power/hibernate.c:977
 resume_store+0xe3/0x130 kernel/power/hibernate.c:1179
 kernfs_fop_write_iter+0x3a2/0x4f0 fs/kernfs/file.c:296
 call_write_iter include/linux/fs.h:2103 [inline]
 new_sync_write fs/read_write.c:507 [inline]
 vfs_write+0xacf/0xe50 fs/read_write.c:594
 ksys_write+0x1a2/0x2c0 fs/read_write.c:647
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7feda0e81ae9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fed9f4030c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007feda0fa0f80 RCX: 00007feda0e81ae9
RDX: 0000000000000012 RSI: 0000000020000040 RDI: 0000000000000005
RBP: 00007feda0ecd47a R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007feda0fa0f80 R15: 00007fff57980778
 </TASK>
PM: Image not found (code -22)

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2023/10/04 20:02 linux-5.15.y b911329317b4 b7d7ff54 .config console log report info ci2-linux-5-15-kasan possible deadlock in bd_register_pending_holders
2023/06/29 16:59 linux-5.15.y 4af60700a60c 134ddc02 .config console log report info ci2-linux-5-15-kasan possible deadlock in bd_register_pending_holders
2023/05/26 14:19 linux-5.15.y 1fe619a7d252 b40ef614 .config console log report info ci2-linux-5-15-kasan possible deadlock in bd_register_pending_holders
* Struck through repros no longer work on HEAD.