syzbot


INFO: task hung in bdev_open

Status: premoderation: reported on 2025/06/25 03:02
Reported-by: syzbot+b2e21696218aba7196bb@syzkaller.appspotmail.com
First crash: 65d, last: 36d
Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in bdev_open block 1 C error 1386 14h21m 458d 0/29 upstream: reported C repro on 2024/05/28 04:10

Sample crash report:
INFO: task udevd:7721 blocked for more than 122 seconds.
      Not tainted 6.12.30-syzkaller-g15178d63ac5e #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:udevd           state:D stack:0     pid:7721  tgid:7721  ppid:109    flags:0x00000000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5945 [inline]
 __schedule+0x132b/0x1e00 kernel/sched/core.c:7789
 __schedule_loop kernel/sched/core.c:7870 [inline]
 schedule+0xc6/0x240 kernel/sched/core.c:7885
 schedule_preempt_disabled+0x14/0x30 kernel/sched/core.c:7942
 __mutex_lock_common kernel/locking/mutex.c:707 [inline]
 __mutex_lock+0x81e/0x1b50 kernel/locking/mutex.c:803
 __mutex_lock_slowpath+0xe/0x20 kernel/locking/mutex.c:1134
 mutex_lock+0x102/0x1c0 kernel/locking/mutex.c:285
 bdev_open+0xd5/0xd60 block/bdev.c:909
 blkdev_open+0x3d1/0x560 block/fops.c:627
 do_dentry_open+0x97b/0x1510 fs/open.c:960
 vfs_open+0x86/0x230 fs/open.c:1090
 do_open fs/namei.c:3774 [inline]
 path_openat+0x2b6c/0x34b0 fs/namei.c:3933
 do_filp_open+0x1c6/0x3e0 fs/namei.c:3960
 do_sys_openat2+0x12c/0x1c0 fs/open.c:1438
 do_sys_open fs/open.c:1453 [inline]
 __do_sys_openat fs/open.c:1469 [inline]
 __se_sys_openat fs/open.c:1464 [inline]
 __x64_sys_openat+0x13a/0x170 fs/open.c:1464
 x64_sys_call+0xe69/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:258
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x58/0xf0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7f29dc8a7407
RSP: 002b:00007ffc9b2b4b90 EFLAGS: 00000202 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f29dd05e880 RCX: 00007f29dc8a7407
RDX: 00000000000a0800 RSI: 00005644b081c590 RDI: ffffffffffffff9c
RBP: 00005644b05e12c0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 00005644b082c540
R13: 00005644b0826990 R14: 0000000000000000 R15: 00005644b082c540
 </TASK>
INFO: task syz.3.2593:8440 blocked for more than 123 seconds.
      Not tainted 6.12.30-syzkaller-g15178d63ac5e #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.2593      state:D stack:0     pid:8440  tgid:8439  ppid:7507   flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5945 [inline]
 __schedule+0x132b/0x1e00 kernel/sched/core.c:7789
 __schedule_loop kernel/sched/core.c:7870 [inline]
 schedule+0xc6/0x240 kernel/sched/core.c:7885
 io_schedule+0x89/0xe0 kernel/sched/core.c:8697
 folio_wait_bit_common+0x6ae/0x910 mm/filemap.c:1336
 folio_put_wait_locked mm/filemap.c:1500 [inline]
 do_read_cache_folio+0x14d/0x4d0 mm/filemap.c:3880
 read_cache_folio+0x54/0x90 mm/filemap.c:3930
 read_mapping_folio include/linux/pagemap.h:1019 [inline]
 read_part_sector+0xcc/0x250 block/partitions/core.c:716
 msdos_partition+0x118/0x3000 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+0x81c/0x1610 block/partitions/core.c:687
 loop_reread_partitions+0x64/0x110 drivers/block/loop.c:464
 loop_configure+0xfd8/0x1320 drivers/block/loop.c:1071
 lo_ioctl+0x76c/0x20a0 drivers/block/loop.c:-1
 blkdev_ioctl+0x549/0x680 block/ioctl.c:693
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:907 [inline]
 __se_sys_ioctl+0x135/0x1b0 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:52 [inline]
 do_syscall_64+0x58/0xf0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7fa495f8e9a9
RSP: 002b:00007fa496dcb038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fa4961b5fa0 RCX: 00007fa495f8e9a9
RDX: 0000200000000380 RSI: 0000000000004c0a RDI: 0000000000000003
RBP: 00007fa496010d69 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fa4961b5fa0 R15: 00007ffe1d322dd8
 </TASK>
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 37 Comm: khungtaskd Not tainted 6.12.30-syzkaller-g15178d63ac5e #0 2e49b5e8bba3abd4e44f2eeb6ccfddb4f386a3cf
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
 <TASK>
 __dump_stack+0x21/0x30 lib/dump_stack.c:94
 dump_stack_lvl+0x10c/0x190 lib/dump_stack.c:120
 dump_stack+0x19/0x20 lib/dump_stack.c:129
 nmi_cpu_backtrace+0x2bf/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+0xd8f/0xed0 kernel/hung_task.c:423
 kthread+0x2c7/0x370 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 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Not tainted 6.12.30-syzkaller-g15178d63ac5e #0 2e49b5e8bba3abd4e44f2eeb6ccfddb4f386a3cf
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:pv_native_safe_halt+0x17/0x20 arch/x86/kernel/paravirt.c:106
Code: cc cc cc b8 2f 66 1d fe 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 73 8c 41 00 f3 0f 1e fa 55 48 89 e5 fb f4 <5d> e9 c3 54 02 00 cc cc cc b8 00 00 00 00 90 90 90 90 90 90 90 90
RSP: 0018:ffffc900001a7e00 EFLAGS: 000002c6
RAX: ffff8881f6f00000 RBX: ffff88810366cc00 RCX: ffffffff8585c00e
RDX: 0000000000000001 RSI: 0000000000000004 RDI: 000000000031029c
RBP: ffffc900001a7e00 R08: ffff8881f6f39733 R09: 1ffff1103ede72e6
R10: dffffc0000000000 R11: ffffed103ede72e7 R12: 1ffff110206cd980
R13: 0000000000000001 R14: 0000000000000000 R15: ffffffff87ca7de8
FS:  0000000000000000(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007feff0b82ab8 CR3: 0000000120446000 CR4: 00000000003526b0
Call Trace:
 <TASK>
 arch_safe_halt arch/x86/include/asm/paravirt.h:112 [inline]
 default_idle+0x17/0x30 arch/x86/kernel/process.c:748
 arch_cpu_idle+0xd/0x20 arch/x86/kernel/process.c:785
 default_idle_call+0x3f/0x80 kernel/sched/idle.c:117
 cpuidle_idle_call kernel/sched/idle.c:185 [inline]
 do_idle+0x1a0/0x470 kernel/sched/idle.c:326
 cpu_startup_entry+0x48/0x70 kernel/sched/idle.c:424
 start_secondary+0x12e/0x140 arch/x86/kernel/smpboot.c:314
 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
2025/07/24 08:38 android16-6.12 15178d63ac5e 0c1d6ded .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in bdev_open
2025/07/22 17:52 android16-6.12 88813c11dc64 8e9d1dc1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in bdev_open
2025/07/19 04:38 android16-6.12 2e58e85c038f 7117feec .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in bdev_open
2025/06/25 08:53 android16-6.12 030e00a2d78c 26d77996 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in bdev_open
2025/06/25 05:23 android16-6.12 94ce385c22d5 26d77996 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in bdev_open
2025/06/25 04:54 android16-6.12 94ce385c22d5 26d77996 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in bdev_open
2025/06/25 03:01 android16-6.12 94ce385c22d5 26d77996 .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.