INFO: task hung in bdev_open (2)

Status: premoderation: reported on 2026/05/22 08:47
Reported-by: syzbot+2133e9cef891e1395b06@syzkaller.appspotmail.com
First crash: 76d, last: 2d19h
▶ ▼ Similar bugs (2)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
android-6-12 INFO: task hung in bdev_open 1 28 168d 407d 0/1 auto-obsoleted due to no activity on 2026/05/20 08:04
upstream INFO: task hung in bdev_open prio:low block 1 syz, C error 5900 4h41m 800d 0/29 upstream: reported C repro on 2024/05/28 04:10

Sample crash report:
INFO: task syz-executor:295 blocked for more than 122 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:0     pid:295   tgid:295   ppid:1      flags:0x00000004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:6060 [inline]
 __schedule+0x1496/0x20b0 kernel/sched/core.c:7880
 __schedule_loop kernel/sched/core.c:7957 [inline]
 schedule+0xc5/0x240 kernel/sched/core.c:7972
 schedule_preempt_disabled+0x14/0x30 kernel/sched/core.c:8029
 __mutex_lock_common kernel/locking/mutex.c:707 [inline]
 __mutex_lock+0x902/0x1b90 kernel/locking/mutex.c:806
 __mutex_lock_slowpath+0xe/0x20 kernel/locking/mutex.c:1136
 mutex_lock+0x113/0x1d0 kernel/locking/mutex.c:285
 bdev_open+0xe3/0xd30 block/bdev.c:926
 blkdev_open+0x3d0/0x560 block/fops.c:627
 do_dentry_open+0x97c/0x1510 fs/open.c:960
 vfs_open+0x86/0x240 fs/open.c:1092
 do_open fs/namei.c:3782 [inline]
 path_openat+0x2c49/0x35a0 fs/namei.c:3941
 do_filp_open+0x1f2/0x440 fs/namei.c:3968
 do_sys_openat2+0x134/0x1d0 fs/open.c:1440
 do_sys_open fs/open.c:1455 [inline]
 __do_sys_openat fs/open.c:1471 [inline]
 __se_sys_openat fs/open.c:1466 [inline]
 __x64_sys_openat+0x13a/0x170 fs/open.c:1466
 x64_sys_call+0xe69/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:258
 do_syscall_x64 arch/x86/entry/common.c:47 [inline]
 do_syscall_64+0x57/0xf0 arch/x86/entry/common.c:78
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7ffa9cd59197
RSP: 002b:00007ffdd7aeea80 EFLAGS: 00000202 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 0000555575f3d500 RCX: 00007ffa9cd59197
RDX: 0000000000000002 RSI: 00007ffdd7aeebb0 RDI: ffffffffffffff9c
RBP: 00007ffdd7aeeb5c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000021
R13: 00000000000927c0 R14: 000000000000b539 R15: 00007ffdd7aeebb0
 </TASK>
INFO: task udevd:324 blocked for more than 123 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:udevd           state:D stack:0     pid:324   tgid:324   ppid:110    flags:0x00000000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:6060 [inline]
 __schedule+0x1496/0x20b0 kernel/sched/core.c:7880
 __schedule_loop kernel/sched/core.c:7957 [inline]
 schedule+0xc5/0x240 kernel/sched/core.c:7972
 schedule_preempt_disabled+0x14/0x30 kernel/sched/core.c:8029
 __mutex_lock_common kernel/locking/mutex.c:707 [inline]
 __mutex_lock+0x902/0x1b90 kernel/locking/mutex.c:806
 __mutex_lock_slowpath+0xe/0x20 kernel/locking/mutex.c:1136
 mutex_lock+0x113/0x1d0 kernel/locking/mutex.c:285
 bdev_open+0xe3/0xd30 block/bdev.c:926
 blkdev_open+0x3d0/0x560 block/fops.c:627
 do_dentry_open+0x97c/0x1510 fs/open.c:960
 vfs_open+0x86/0x240 fs/open.c:1092
 do_open fs/namei.c:3782 [inline]
 path_openat+0x2c49/0x35a0 fs/namei.c:3941
 do_filp_open+0x1f2/0x440 fs/namei.c:3968
 do_sys_openat2+0x134/0x1d0 fs/open.c:1440
 do_sys_open fs/open.c:1455 [inline]
 __do_sys_openat fs/open.c:1471 [inline]
 __se_sys_openat fs/open.c:1466 [inline]
 __x64_sys_openat+0x13a/0x170 fs/open.c:1466
 x64_sys_call+0xe69/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:258
 do_syscall_x64 arch/x86/entry/common.c:47 [inline]
 do_syscall_64+0x57/0xf0 arch/x86/entry/common.c:78
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7ff1ff0a7407
RSP: 002b:00007ffe1fa9df60 EFLAGS: 00000202 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007ff1ff748880 RCX: 00007ff1ff0a7407
RDX: 00000000000a0800 RSI: 00005558e4882610 RDI: ffffffffffffff9c
RBP: 00005558e487f2c0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 00005558e4ac5540
R13: 00005558e4aba8b0 R14: 0000000000000000 R15: 00005558e4ac5540
 </TASK>
INFO: task syz.2.121:782 blocked for more than 123 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.121       state:D stack:0     pid:782   tgid:781   ppid:296    flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:6060 [inline]
 __schedule+0x1496/0x20b0 kernel/sched/core.c:7880
 __schedule_loop kernel/sched/core.c:7957 [inline]
 schedule+0xc5/0x240 kernel/sched/core.c:7972
 io_schedule+0x88/0xe0 kernel/sched/core.c:8786
 folio_wait_bit_common+0x6a4/0x940 mm/filemap.c:1356
 folio_put_wait_locked mm/filemap.c:1520 [inline]
 do_read_cache_folio+0x17c/0x610 mm/filemap.c:4060
 read_cache_folio+0x54/0x90 mm/filemap.c:4110
 read_mapping_folio include/linux/pagemap.h:1021 [inline]
 read_part_sector+0xcc/0x250 block/partitions/core.c:716
 msdos_partition+0x111/0x3000 block/partitions/msdos.c:592
 check_partition block/partitions/core.c:138 [inline]
 blk_add_partitions block/partitions/core.c:583 [inline]
 bdev_disk_changed+0x823/0x15d0 block/partitions/core.c:687
 loop_reread_partitions+0x64/0x110 drivers/block/loop.c:467
 loop_configure+0x106f/0x13a0 drivers/block/loop.c:1078
 lo_ioctl+0xa78/0x2010 drivers/block/loop.c:1520
 blkdev_ioctl+0x54b/0x690 block/ioctl.c:699
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:907 [inline]
 __se_sys_ioctl+0x132/0x1b0 fs/ioctl.c:893
 __x64_sys_ioctl+0x7f/0xa0 fs/ioctl.c:893
 x64_sys_call+0x1878/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:17
 do_syscall_x64 arch/x86/entry/common.c:47 [inline]
 do_syscall_64+0x57/0xf0 arch/x86/entry/common.c:78
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7f54bfd9e019
RSP: 002b:00007f54c0c13028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f54c0025fa0 RCX: 00007f54bfd9e019
RDX: 0000200000000080 RSI: 0000000000004c0a RDI: 0000000000000003
RBP: 00007f54bfe3500c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f54c0026038 R14: 00007f54c0025fa0 R15: 00007fff8e1d83f8
 </TASK>
INFO: task syz.2.121:785 blocked for more than 124 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.121       state:D stack:0     pid:785   tgid:781   ppid:296    flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:6060 [inline]
 __schedule+0x1496/0x20b0 kernel/sched/core.c:7880
 __schedule_loop kernel/sched/core.c:7957 [inline]
 schedule+0xc5/0x240 kernel/sched/core.c:7972
 blk_mq_freeze_queue_wait+0xf3/0x180 block/blk-mq.c:210
 blk_freeze_queue+0xc7/0x100 block/blk-mq.c:237
 blk_mq_freeze_queue+0x19/0x30 block/blk-mq.c:246
 loop_set_status+0x1fd/0x700 drivers/block/loop.c:1232
 loop_set_status64 drivers/block/loop.c:1363 [inline]
 lo_ioctl+0xc03/0x2010 drivers/block/loop.c:1536
 blkdev_ioctl+0x54b/0x690 block/ioctl.c:699
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:907 [inline]
 __se_sys_ioctl+0x132/0x1b0 fs/ioctl.c:893
 __x64_sys_ioctl+0x7f/0xa0 fs/ioctl.c:893
 x64_sys_call+0x1878/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:17
 do_syscall_x64 arch/x86/entry/common.c:47 [inline]
 do_syscall_64+0x57/0xf0 arch/x86/entry/common.c:78
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7f54bfd9e019
RSP: 002b:00007f54c0bf2028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f54c0026090 RCX: 00007f54bfd9e019
RDX: 0000200000000280 RSI: 0000000000004c04 RDI: 0000000000000003
RBP: 00007f54bfe3500c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f54c0026128 R14: 00007f54c0026090 R15: 00007fff8e1d83f8
 </TASK>
INFO: task syz.0.139:831 blocked for more than 124 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.139       state:D stack:0     pid:831   tgid:830   ppid:293    flags:0x00000004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:6060 [inline]
 __schedule+0x1496/0x20b0 kernel/sched/core.c:7880
 __schedule_loop kernel/sched/core.c:7957 [inline]
 schedule+0xc5/0x240 kernel/sched/core.c:7972
 schedule_preempt_disabled+0x14/0x30 kernel/sched/core.c:8029
 __mutex_lock_common kernel/locking/mutex.c:707 [inline]
 __mutex_lock+0x902/0x1b90 kernel/locking/mutex.c:806
 __mutex_lock_slowpath+0xe/0x20 kernel/locking/mutex.c:1136
 mutex_lock+0x113/0x1d0 kernel/locking/mutex.c:285
 bdev_open+0xe3/0xd30 block/bdev.c:926
 blkdev_open+0x3d0/0x560 block/fops.c:627
 do_dentry_open+0x97c/0x1510 fs/open.c:960
 vfs_open+0x86/0x240 fs/open.c:1092
 do_open fs/namei.c:3782 [inline]
 path_openat+0x2c49/0x35a0 fs/namei.c:3941
 do_filp_open+0x1f2/0x440 fs/namei.c:3968
 do_sys_openat2+0x134/0x1d0 fs/open.c:1440
 do_sys_open fs/open.c:1455 [inline]
 __do_sys_openat fs/open.c:1471 [inline]
 __se_sys_openat fs/open.c:1466 [inline]
 __x64_sys_openat+0x13a/0x170 fs/open.c:1466
 x64_sys_call+0xe69/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:258
 do_syscall_x64 arch/x86/entry/common.c:47 [inline]
 do_syscall_64+0x57/0xf0 arch/x86/entry/common.c:78
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7f5708d5e84e
RSP: 002b:00007f5709c96b28 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f5709c976c0 RCX: 00007f5708d5e84e
RDX: 00000000361c2817 RSI: 00007f5709c96c00 RDI: ffffffffffffff9c
RBP: 00007f5709c96c00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: cccccccccccccccd
R13: 00007f5709026038 R14: 00007f5709025fa0 R15: 00007ffd2ee7abb8
 </TASK>
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 37 Comm: khungtaskd Not tainted syzkaller #0 7f3b23dcf55806c758f3cdeb9210fc77c27c120f
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
 <TASK>
 __dump_stack+0x21/0x30 lib/dump_stack.c:94
 dump_stack_lvl+0x140/0x1c0 lib/dump_stack.c:120
 dump_stack+0x19/0x20 lib/dump_stack.c:129
 nmi_cpu_backtrace+0x2ba/0x2d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x142/0x2c0 lib/nmi_backtrace.c:62
 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:41
 trigger_all_cpu_backtrace include/linux/nmi.h:158 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:267 [inline]
 watchdog+0xe45/0xf90 kernel/hung_task.c:423
 kthread+0x2c7/0x360 kernel/kthread.c:389
 ret_from_fork+0x67/0xa0 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted syzkaller #0 7f3b23dcf55806c758f3cdeb9210fc77c27c120f
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:116
Code: cc cc cc cc cc cc cc b8 48 b7 61 d3 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 23 29 43 00 55 48 89 e5 fb f4 <5d> c3 cc cc cc cc cc cc cc cc cc cc cc b8 00 00 00 00 90 90 90 90
RSP: 0018:ffffffff87407da0 EFLAGS: 000002c2
RAX: ffff8881f6e00000 RBX: ffffffff874156c0 RCX: ffffffff85a434fd
RDX: 0000000000000001 RSI: 0000000000000004 RDI: 00000000000f71e4
RBP: ffffffff87407da0 R08: ffff8881f6e395eb R09: 1ffff1103edc72bd
R10: dffffc0000000000 R11: ffffed103edc72be R12: 0000000000000000
R13: 1ffffffff0e82ad8 R14: dffffc0000000000 R15: ffffffff87ecbee8
FS:  0000000000000000(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f66bc1ef2f8 CR3: 000000010c7ce000 CR4: 00000000003526b0
Call Trace:
 <TASK>
 arch_safe_halt arch/x86/include/asm/paravirt.h:-1 [inline]
 default_idle+0x17/0x30 arch/x86/kernel/process.c:754
 arch_cpu_idle+0xd/0x20 arch/x86/kernel/process.c:791
 default_idle_call+0x3e/0x80 kernel/sched/idle.c:117
 cpuidle_idle_call kernel/sched/idle.c:193 [inline]
 do_idle+0x1df/0x570 kernel/sched/idle.c:346
 cpu_startup_entry+0x47/0x60 kernel/sched/idle.c:445
 rest_init+0x10b/0x130 init/main.c:760
 start_kernel+0x462/0x4bb init/main.c:1242
 x86_64_start_reservations+0x2e/0x30 arch/x86/kernel/head64.c:507
 x86_64_start_kernel+0x6a/0x7b arch/x86/kernel/head64.c:488
 common_startup_64+0x13b/0x157
 </TASK>

Crashes (4):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/03 22:06 android16-6.12 5098494bc7f3 6b7c9f71 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in bdev_open
2026/08/03 21:46 android16-6.12 5098494bc7f3 6b7c9f71 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in bdev_open
2026/08/02 19:19 android16-6.12 1a138e24e292 e611ffe1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in bdev_open
2026/05/22 08:46 android16-6.12 9d40b257ba08 70ae9b03 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in bdev_open
* Struck through repros no longer work on HEAD.