INFO: task hung in bdev_open (2)

Status: premoderation: reported C repro on 2026/05/22 08:47
Reported-by: syzbot+2133e9cef891e1395b06@syzkaller.appspotmail.com
First crash: 112d, last: 1d06h
▶ ▼ 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 204d 443d 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 6238 3h43m 836d 0/29 upstream: reported C repro on 2024/05/28 04:10

Sample crash report:
INFO: task udevd:318 blocked for more than 122 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:udevd           state:D stack:0     pid:318   tgid:318   ppid:110    flags:0x00000000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:6063 [inline]
 __schedule+0x1496/0x20b0 kernel/sched/core.c:7883
 __schedule_loop kernel/sched/core.c:7960 [inline]
 schedule+0xc5/0x240 kernel/sched/core.c:7975
 schedule_preempt_disabled+0x14/0x30 kernel/sched/core.c:8032
 __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:954
 vfs_open+0x86/0x240 fs/open.c:1086
 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:1434
 do_sys_open fs/open.c:1449 [inline]
 __do_sys_openat fs/open.c:1465 [inline]
 __se_sys_openat fs/open.c:1460 [inline]
 __x64_sys_openat+0x13a/0x170 fs/open.c:1460
 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: 0033:0x7f94944a7407
RSP: 002b:00007fffe9387fc0 EFLAGS: 00000202 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f9494bad880 RCX: 00007f94944a7407
RDX: 00000000000a0800 RSI: 00005592f066bb40 RDI: ffffffffffffff9c
RBP: 00005592f04212c0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 00005592f0753090
R13: 00005592f06620f0 R14: 0000000000000000 R15: 00005592f0753090
 </TASK>
INFO: task syz.2.17:383 blocked for more than 123 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.17        state:D stack:0     pid:383   tgid:383   ppid:379    flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:6063 [inline]
 __schedule+0x1496/0x20b0 kernel/sched/core.c:7883
 __schedule_loop kernel/sched/core.c:7960 [inline]
 schedule+0xc5/0x240 kernel/sched/core.c:7975
 io_schedule+0x85/0x150 kernel/sched/core.c:8790
 folio_wait_bit_common+0x6a4/0x940 mm/filemap.c:1379
 folio_put_wait_locked mm/filemap.c:1543 [inline]
 do_read_cache_folio+0x150/0x960 mm/filemap.c:4090
 read_cache_folio+0x54/0x90 mm/filemap.c:4140
 read_mapping_folio include/linux/pagemap.h:1029 [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:906 [inline]
 __se_sys_ioctl+0x126/0x1b0 fs/ioctl.c:892
 __x64_sys_ioctl+0x7f/0xa0 fs/ioctl.c:892
 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: 0033:0x7f803cd9e159
RSP: 002b:00007ffdebdbe978 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f803d025fa0 RCX: 00007f803cd9e159
RDX: 0000200000000080 RSI: 0000000000004c0a RDI: 0000000000000005
RBP: 00007f803ce3503b R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f803d025fac R14: 00007f803d025fa0 R15: 00007f803d025fa0
 </TASK>
INFO: task syz-executor:386 blocked for more than 123 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:386   tgid:386   ppid:1      flags:0x00000004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:6063 [inline]
 __schedule+0x1496/0x20b0 kernel/sched/core.c:7883
 __schedule_loop kernel/sched/core.c:7960 [inline]
 schedule+0xc5/0x240 kernel/sched/core.c:7975
 schedule_preempt_disabled+0x14/0x30 kernel/sched/core.c:8032
 __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:954
 vfs_open+0x86/0x240 fs/open.c:1086
 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:1434
 do_sys_open fs/open.c:1449 [inline]
 __do_sys_openat fs/open.c:1465 [inline]
 __se_sys_openat fs/open.c:1460 [inline]
 __x64_sys_openat+0x13a/0x170 fs/open.c:1460
 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: 0033:0x7fa6299592d7
RSP: 002b:00007ffe1cfc5ae0 EFLAGS: 00000202 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 0000555591bb3500 RCX: 00007fa6299592d7
RDX: 0000000000000002 RSI: 00007ffe1cfc5c10 RDI: ffffffffffffff9c
RBP: 0000000000000003 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000
R13: 00007fa629bec3e0 R14: 0000000000000003 R15: 00007ffe1cfc5c10
 </TASK>
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 37 Comm: khungtaskd Not tainted syzkaller #0 854a78f96d1de0e57c2b3161b903feab84b64500
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+0x2c4/0x360 kernel/kthread.c:389
 ret_from_fork+0x64/0xa0 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 854a78f96d1de0e57c2b3161b903feab84b64500
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 4f eb e0 55 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 03 68 42 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: ffffffff85a4f4fd
RDX: 0000000000000001 RSI: 0000000000000004 RDI: 000000000007bbcc
RBP: ffffffff87407da0 R08: ffff8881f6e395eb R09: 1ffff1103edc72bd
R10: dffffc0000000000 R11: ffffed103edc72be R12: 0000000000000000
R13: 1ffffffff0e82ad8 R14: dffffc0000000000 R15: ffffffff87ecdda8
FS:  0000000000000000(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055557ebfe918 CR3: 0000000107fd2000 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+0x2fc/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 (7):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/09/09 16:48 android16-6.12 d768b2f486b5 8387c273 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in bdev_open
2026/09/10 16:29 android16-6.12 89698cd757af 1fe56c0a .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in bdev_open
2026/09/09 13:44 android16-6.12 d768b2f486b5 8387c273 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in bdev_open
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.