syzbot


INFO: task hung in blkdev_get_by_dev (4)

Status: upstream: reported on 2025/05/27 06:24
Reported-by: syzbot+5cf071d639967d79b221@syzkaller.appspotmail.com
First crash: 14d, last: 14d
Similar bugs (9)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 INFO: task hung in blkdev_get_by_dev origin:lts-only C done 25 211d 498d 3/3 fixed on 2025/01/02 10:34
linux-5.15 INFO: task hung in blkdev_get_by_dev (2) 1 639d 639d 0/3 auto-obsoleted due to no activity on 2023/12/18 22:46
upstream INFO: task hung in blkdev_get_by_dev (3) block 1 1189d 1189d 0/28 auto-closed as invalid on 2022/05/08 09:47
linux-5.15 INFO: task hung in blkdev_get_by_dev 1 770d 770d 0/3 auto-obsoleted due to no activity on 2023/08/23 09:06
linux-5.15 INFO: task hung in blkdev_get_by_dev (3) 17 274d 495d 0/3 auto-obsoleted due to no activity on 2024/12/17 17:06
upstream INFO: task hung in blkdev_get_by_dev fs 1 1568d 1568d 0/28 auto-closed as invalid on 2021/05/23 22:12
upstream INFO: task hung in blkdev_get_by_dev (4) block 1 1018d 1018d 0/28 auto-obsoleted due to no activity on 2022/11/25 11:03
upstream INFO: task hung in blkdev_get_by_dev (2) block 1727 1220d 1300d 0/28 closed as dup on 2021/11/21 14:02
upstream INFO: task hung in blkdev_get_by_dev (5) block C error error 32 59d 830d 0/28 upstream: reported C repro on 2023/03/02 18:11

Sample crash report:
INFO: task udevd:4167 blocked for more than 143 seconds.
      Not tainted 5.15.184-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:udevd           state:D stack:    0 pid: 4167 ppid:  3643 flags:0x00000004
Call trace:
 __switch_to+0x2f4/0x558 arch/arm64/kernel/process.c:521
 context_switch kernel/sched/core.c:5030 [inline]
 __schedule+0xe00/0x1c0c kernel/sched/core.c:6376
 schedule+0x11c/0x1c8 kernel/sched/core.c:6459
 schedule_preempt_disabled+0x18/0x2c kernel/sched/core.c:6518
 __mutex_lock_common+0xa9c/0x1edc kernel/locking/mutex.c:669
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0xac/0x11c kernel/locking/mutex.c:743
 blkdev_get_by_dev+0x120/0x874 block/bdev.c:820
 blkdev_open+0x108/0x27c block/fops.c:466
 do_dentry_open+0x760/0xebc fs/open.c:826
 vfs_open+0x7c/0x90 fs/open.c:956
 do_open fs/namei.c:3608 [inline]
 path_openat+0x1f80/0x26e4 fs/namei.c:3742
 do_filp_open+0x164/0x330 fs/namei.c:3769
 do_sys_openat2+0x128/0x3d8 fs/open.c:1253
 do_sys_open fs/open.c:1269 [inline]
 __do_sys_openat fs/open.c:1285 [inline]
 __se_sys_openat fs/open.c:1280 [inline]
 __arm64_sys_openat+0x120/0x154 fs/open.c:1280
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
 el0_svc+0x78/0x1e0 arch/arm64/kernel/entry-common.c:608
 el0t_64_sync_handler+0xcc/0xe4 arch/arm64/kernel/entry-common.c:626
 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584
INFO: task syz.0.184:4679 blocked for more than 143 seconds.
      Not tainted 5.15.184-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.184       state:D stack:    0 pid: 4679 ppid:  4029 flags:0x00000009
Call trace:
 __switch_to+0x2f4/0x558 arch/arm64/kernel/process.c:521
 context_switch kernel/sched/core.c:5030 [inline]
 __schedule+0xe00/0x1c0c kernel/sched/core.c:6376
 schedule+0x11c/0x1c8 kernel/sched/core.c:6459
 schedule_preempt_disabled+0x18/0x2c kernel/sched/core.c:6518
 __mutex_lock_common+0xa9c/0x1edc kernel/locking/mutex.c:669
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0xac/0x11c kernel/locking/mutex.c:743
 blkdev_put+0xdc/0x6ac block/bdev.c:915
 blkdev_close+0x74/0xb0 block/fops.c:478
 __fput+0x1c0/0x7f8 fs/file_table.c:311
 ____fput+0x20/0x30 fs/file_table.c:339
 task_work_run+0x12c/0x1e0 kernel/task_work.c:188
 tracehook_notify_resume include/linux/tracehook.h:189 [inline]
 do_notify_resume+0x24b4/0x3128 arch/arm64/kernel/signal.c:949
 prepare_exit_to_user_mode arch/arm64/kernel/entry-common.c:133 [inline]
 exit_to_user_mode arch/arm64/kernel/entry-common.c:138 [inline]
 el0_svc+0xf0/0x1e0 arch/arm64/kernel/entry-common.c:609
 el0t_64_sync_handler+0xcc/0xe4 arch/arm64/kernel/entry-common.c:626
 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584
INFO: task syz.0.184:4680 blocked for more than 143 seconds.
      Not tainted 5.15.184-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.184       state:D stack:    0 pid: 4680 ppid:  4029 flags:0x00000001
Call trace:
 __switch_to+0x2f4/0x558 arch/arm64/kernel/process.c:521
 context_switch kernel/sched/core.c:5030 [inline]
 __schedule+0xe00/0x1c0c kernel/sched/core.c:6376
 schedule+0x11c/0x1c8 kernel/sched/core.c:6459
 io_schedule+0x84/0x160 kernel/sched/core.c:8484
 wait_on_page_bit_common+0x61c/0xa74 mm/filemap.c:1356
 wait_on_page_bit mm/filemap.c:1417 [inline]
 wait_on_page_locked include/linux/pagemap.h:688 [inline]
 wait_on_page_read mm/filemap.c:3437 [inline]
 do_read_cache_page+0x748/0x8f8 mm/filemap.c:3480
 read_cache_page+0x68/0x88 mm/filemap.c:3574
 read_mapping_page include/linux/pagemap.h:515 [inline]
 read_part_sector+0xe8/0x4c4 block/partitions/core.c:731
 adfspart_check_ICS+0xbc/0x560 block/partitions/acorn.c:360
 check_partition block/partitions/core.c:148 [inline]
 blk_add_partitions block/partitions/core.c:616 [inline]
 bdev_disk_changed+0x7fc/0x1378 block/partitions/core.c:702
 blkdev_get_whole+0x2a4/0x344 block/bdev.c:682
 blkdev_get_by_dev+0x224/0x874 block/bdev.c:827
 blkdev_open+0x108/0x27c block/fops.c:466
 do_dentry_open+0x760/0xebc fs/open.c:826
 vfs_open+0x7c/0x90 fs/open.c:956
 do_open fs/namei.c:3608 [inline]
 path_openat+0x1f80/0x26e4 fs/namei.c:3742
 do_filp_open+0x164/0x330 fs/namei.c:3769
 do_sys_openat2+0x128/0x3d8 fs/open.c:1253
 do_sys_open fs/open.c:1269 [inline]
 __do_sys_openat fs/open.c:1285 [inline]
 __se_sys_openat fs/open.c:1280 [inline]
 __arm64_sys_openat+0x120/0x154 fs/open.c:1280
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
 el0_svc+0x78/0x1e0 arch/arm64/kernel/entry-common.c:608
 el0t_64_sync_handler+0xcc/0xe4 arch/arm64/kernel/entry-common.c:626
 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

Showing all locks held in the system:
1 lock held by khungtaskd/27:
 #0: ffff8000143211e0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0xc/0x44 include/linux/rcupdate.h:311
2 locks held by kworker/u4:4/378:
 #0: ffff0000c0029138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x678/0x1140 kernel/workqueue.c:2283
 #1: ffff80001f7d7c00 ((reaper_work).work){+.+.}-{0:0}, at: process_one_work+0x6b8/0x1140 kernel/workqueue.c:2285
1 lock held by udevd/3643:
2 locks held by getty/3794:
 #0: ffff0000d357f098 (&tty->ldisc_sem){++++}-{0:0}, at: ldsem_down_read+0x40/0x50 drivers/tty/tty_ldsem.c:340
 #1: ffff80001b7802e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x2f0/0xf6c drivers/tty/n_tty.c:2158
2 locks held by syz-executor/4033:
 #0: ffff0000cbe59d18 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_put+0xdc/0x6ac block/bdev.c:915
 #1: ffff0000cbfa3468 (&lo->lo_mutex){+.+.}-{3:3}, at: __loop_clr_fd+0xa4/0x978 drivers/block/loop.c:1366
3 locks held by syz-executor/4037:
2 locks held by kworker/1:7/4076:
 #0: ffff0000c0020938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x678/0x1140 kernel/workqueue.c:2283
 #1: ffff80001f537c00 ((work_completion)(&pwq->unbound_release_work)){+.+.}-{0:0}, at: process_one_work+0x6b8/0x1140 kernel/workqueue.c:2285
1 lock held by udevd/4167:
 #0: ffff0000cc078518 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0x120/0x874 block/bdev.c:820
1 lock held by udevd/4170:
2 locks held by kworker/1:11/4352:
 #0: ffff0000c0021938 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x678/0x1140 kernel/workqueue.c:2283
 #1: ffff80001f997c00 ((work_completion)(&rew.rew_work)){+.+.}-{0:0}, at: process_one_work+0x6b8/0x1140 kernel/workqueue.c:2285
1 lock held by syz.0.184/4679:
 #0: ffff0000cc078518 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_put+0xdc/0x6ac block/bdev.c:915
1 lock held by syz.0.184/4680:
 #0: ffff0000cc078518 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0x120/0x874 block/bdev.c:820
1 lock held by udevd/5288:
 #0: ffff0000cbe59d18 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0x120/0x874 block/bdev.c:820
1 lock held by syz-executor/8002:
 #0: ffff800014325ca8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:290 [inline]
 #0: ffff800014325ca8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x2f0/0x5e0 kernel/rcu/tree_exp.h:845
1 lock held by syz.4.1559/9278:
 #0: ffff0000d3775d18 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock_killable include/linux/mmap_lock.h:87 [inline]
 #0: ffff0000d3775d18 (&mm->mmap_lock){++++}-{3:3}, at: vm_mmap_pgoff+0x138/0x284 mm/util.c:549

=============================================


Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/05/27 06:29 linux-5.15.y 98f47d0e9b8c 874a1386 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 INFO: task hung in blkdev_get_by_dev
2025/05/27 06:24 linux-5.15.y 98f47d0e9b8c 874a1386 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 INFO: task hung in blkdev_get_by_dev
2025/05/27 06:24 linux-5.15.y 98f47d0e9b8c 874a1386 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 INFO: task hung in blkdev_get_by_dev
* Struck through repros no longer work on HEAD.