Extracting prog: 4m41.914143903s
Minimizing prog: 18m16.549488274s
Simplifying prog options: 0s
Extracting C: 7m18.509295444s
Simplifying C: 25m29.553038058s
extracting reproducer from 1 programs
testing a last program of every proc
single: executing 1 programs separately with timeout 6m0s
testing program (duration=6m0s, {Threaded:true Repeat:true RepeatTimes:0 Procs:5 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): openat$nullb-fallocate
detailed listing:
executing program 0:
r0 = openat$nullb(0xffffffffffffff9c, &(0x7f0000000080), 0x10b502, 0x0)
fallocate(r0, 0x11, 0x600, 0x1800000007c000)
program crashed: INFO: task hung in blkdev_fallocate
single: successfully extracted reproducer
found reproducer with 2 syscalls
minimizing guilty program
testing program (duration=6m0s, {Threaded:true Repeat:true RepeatTimes:0 Procs:5 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): openat$nullb
detailed listing:
executing program 0:
openat$nullb(0xffffffffffffff9c, &(0x7f0000000080), 0x10b502, 0x0)
program did not crash
testing program (duration=6m0s, {Threaded:true Repeat:true RepeatTimes:0 Procs:5 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): fallocate
detailed listing:
executing program 0:
fallocate(0xffffffffffffffff, 0x11, 0x600, 0x1800000007c000)
program did not crash
testing program (duration=6m0s, {Threaded:true Repeat:true RepeatTimes:0 Procs:5 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): openat$nullb-fallocate
detailed listing:
executing program 0:
r0 = openat$nullb(0xffffffffffffff9c, 0x0, 0x10b502, 0x0)
fallocate(r0, 0x11, 0x600, 0x1800000007c000)
program did not crash
extracting C reproducer
testing compiled C program (duration=6m0s, {Threaded:true Repeat:true RepeatTimes:0 Procs:5 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): openat$nullb-fallocate
VM was preempted during C execution: failed to run command in VM: instance is preempted, retrying
testing compiled C program (duration=6m0s, {Threaded:true Repeat:true RepeatTimes:0 Procs:5 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): openat$nullb-fallocate
program crashed: INFO: task hung in blkdev_fallocate
simplifying C reproducer
testing compiled C program (duration=6m0s, {Threaded:false Repeat:true RepeatTimes:0 Procs:5 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): openat$nullb-fallocate
program crashed: INFO: task hung in blkdev_fallocate
testing compiled C program (duration=6m0s, {Threaded:false Repeat:true RepeatTimes:0 Procs:1 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): openat$nullb-fallocate
program crashed: no output from test machine
a never seen crash title: no output from test machine, ignore
testing compiled C program (duration=6m0s, {Threaded:false Repeat:true RepeatTimes:0 Procs:5 Slowdown:1 Sandbox: SandboxArg:0 Leak:false NetInjection:false NetDevices:false NetReset:false Cgroups:false BinfmtMisc:false CloseFDs:false KCSAN:false DevlinkPCI:false NicVF:false USB:false VhciInjection:false Wifi:false IEEE802154:true Sysctl:true Swap:false UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): openat$nullb-fallocate
program crashed: INFO: task hung in blkdev_fallocate
testing compiled C program (duration=6m0s, {Threaded:false Repeat:true RepeatTimes:0 Procs:5 Slowdown:1 Sandbox: SandboxArg:0 Leak:false NetInjection:false NetDevices:false NetReset:false Cgroups:false BinfmtMisc:false CloseFDs:false KCSAN:false DevlinkPCI:false NicVF:false USB:false VhciInjection:false Wifi:false IEEE802154:false Sysctl:true Swap:false UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): openat$nullb-fallocate
program crashed: INFO: task hung in blkdev_fallocate
testing compiled C program (duration=6m0s, {Threaded:false Repeat:true RepeatTimes:0 Procs:5 Slowdown:1 Sandbox: SandboxArg:0 Leak:false NetInjection:false NetDevices:false NetReset:false Cgroups:false BinfmtMisc:false CloseFDs:false KCSAN:false DevlinkPCI:false NicVF:false USB:false VhciInjection:false Wifi:false IEEE802154:false Sysctl:true Swap:false UseTmpDir:false HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): openat$nullb-fallocate
program crashed: INFO: task hung in corrupted
a never seen crash title: INFO: task hung in corrupted, ignore
testing compiled C program (duration=6m0s, {Threaded:false Repeat:true RepeatTimes:0 Procs:5 Slowdown:1 Sandbox: SandboxArg:0 Leak:false NetInjection:false NetDevices:false NetReset:false Cgroups:false BinfmtMisc:false CloseFDs:false KCSAN:false DevlinkPCI:false NicVF:false USB:false VhciInjection:false Wifi:false IEEE802154:false Sysctl:true Swap:false UseTmpDir:true HandleSegv:false Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): openat$nullb-fallocate
program crashed: INFO: task hung in blkdev_fallocate
testing compiled C program (duration=6m0s, {Threaded:false Repeat:true RepeatTimes:0 Procs:5 Slowdown:1 Sandbox: SandboxArg:0 Leak:false NetInjection:false NetDevices:false NetReset:false Cgroups:false BinfmtMisc:false CloseFDs:false KCSAN:false DevlinkPCI:false NicVF:false USB:false VhciInjection:false Wifi:false IEEE802154:false Sysctl:false Swap:false UseTmpDir:true HandleSegv:false Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): openat$nullb-fallocate
program crashed: INFO: task hung in blkdev_fallocate
testing program (duration=6m0s, {Threaded:false Repeat:true RepeatTimes:0 Procs:5 Slowdown:1 Sandbox: SandboxArg:0 Leak:false NetInjection:false NetDevices:false NetReset:false Cgroups:false BinfmtMisc:false CloseFDs:false KCSAN:false DevlinkPCI:false NicVF:false USB:false VhciInjection:false Wifi:false IEEE802154:false Sysctl:false Swap:false UseTmpDir:true HandleSegv:false Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): openat$nullb-fallocate
detailed listing:
executing program 0:
r0 = openat$nullb(0xffffffffffffff9c, &(0x7f0000000080), 0x10b502, 0x0)
fallocate(r0, 0x11, 0x600, 0x1800000007c000)
program crashed: INFO: task hung in blkdev_fallocate
validation run: crashed=true
testing program (duration=6m0s, {Threaded:false Repeat:true RepeatTimes:0 Procs:5 Slowdown:1 Sandbox: SandboxArg:0 Leak:false NetInjection:false NetDevices:false NetReset:false Cgroups:false BinfmtMisc:false CloseFDs:false KCSAN:false DevlinkPCI:false NicVF:false USB:false VhciInjection:false Wifi:false IEEE802154:false Sysctl:false Swap:false UseTmpDir:true HandleSegv:false Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): openat$nullb-fallocate
detailed listing:
executing program 0:
r0 = openat$nullb(0xffffffffffffff9c, &(0x7f0000000080), 0x10b502, 0x0)
fallocate(r0, 0x11, 0x600, 0x1800000007c000)
program crashed: INFO: task hung in blkdev_fallocate
validation run: crashed=true
testing program (duration=6m0s, {Threaded:false Repeat:true RepeatTimes:0 Procs:5 Slowdown:1 Sandbox: SandboxArg:0 Leak:false NetInjection:false NetDevices:false NetReset:false Cgroups:false BinfmtMisc:false CloseFDs:false KCSAN:false DevlinkPCI:false NicVF:false USB:false VhciInjection:false Wifi:false IEEE802154:false Sysctl:false Swap:false UseTmpDir:true HandleSegv:false Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): openat$nullb-fallocate
detailed listing:
executing program 0:
r0 = openat$nullb(0xffffffffffffff9c, &(0x7f0000000080), 0x10b502, 0x0)
fallocate(r0, 0x11, 0x600, 0x1800000007c000)
program crashed: INFO: task hung in blkdev_fallocate
validation run: crashed=true
reproducing took 1h5m13.115873731s
repro crashed as (corrupted=false):
INFO: task syz.1.18:5940 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.18 state:D stack:27864 pid:5940 tgid:5940 ppid:5769 task_flags:0x400040 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5504 [inline]
__schedule+0x16dc/0x5500 kernel/sched/core.c:7228
__schedule_loop kernel/sched/core.c:7307 [inline]
rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7603
rt_mutex_slowlock_block kernel/locking/rtmutex.c:1670 [inline]
__rt_mutex_slowlock kernel/locking/rtmutex.c:1747 [inline]
__rt_mutex_slowlock_locked+0x1f84/0x25b0 kernel/locking/rtmutex.c:1787
rt_mutex_slowlock+0xbd/0x170 kernel/locking/rtmutex.c:1827
__rt_mutex_lock kernel/locking/rtmutex.c:1842 [inline]
rwbase_write_lock+0x14c/0x720 kernel/locking/rwbase_rt.c:251
inode_lock include/linux/fs.h:1029 [inline]
blkdev_fallocate+0x263/0x550 block/fops.c:907
vfs_fallocate+0x663/0x7f0 fs/open.c:338
ksys_fallocate fs/open.c:362 [inline]
__do_sys_fallocate fs/open.c:367 [inline]
__se_sys_fallocate fs/open.c:365 [inline]
__x64_sys_fallocate+0xbf/0x110 fs/open.c:365
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ff2f04fce59
RSP: 002b:00007fffc0cd3c58 EFLAGS: 00000246 ORIG_RAX: 000000000000011d
RAX: ffffffffffffffda RBX: 00007ff2f0775fa0 RCX: 00007ff2f04fce59
RDX: 0000000000000600 RSI: 0000000000000011 RDI: 0000000000000003
RBP: 00007ff2f0592d6f R08: 0000000000000000 R09: 0000000000000000
R10: 001800000007c000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ff2f0775fac R14: 00007ff2f0775fa0 R15: 00007ff2f0775fa0
INFO: task syz.3.20:5941 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.20 state:D stack:27864 pid:5941 tgid:5941 ppid:5772 task_flags:0x400040 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5504 [inline]
__schedule+0x16dc/0x5500 kernel/sched/core.c:7228
__schedule_loop kernel/sched/core.c:7307 [inline]
rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7603
rt_mutex_slowlock_block kernel/locking/rtmutex.c:1670 [inline]
__rt_mutex_slowlock kernel/locking/rtmutex.c:1747 [inline]
__rt_mutex_slowlock_locked+0x1f84/0x25b0 kernel/locking/rtmutex.c:1787
rt_mutex_slowlock+0xbd/0x170 kernel/locking/rtmutex.c:1827
__rt_mutex_lock kernel/locking/rtmutex.c:1842 [inline]
rwbase_write_lock+0x14c/0x720 kernel/locking/rwbase_rt.c:251
inode_lock include/linux/fs.h:1029 [inline]
blkdev_fallocate+0x263/0x550 block/fops.c:907
vfs_fallocate+0x663/0x7f0 fs/open.c:338
ksys_fallocate fs/open.c:362 [inline]
__do_sys_fallocate fs/open.c:367 [inline]
__se_sys_fallocate fs/open.c:365 [inline]
__x64_sys_fallocate+0xbf/0x110 fs/open.c:365
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f0d8d9cce59
RSP: 002b:00007ffd3c4ebee8 EFLAGS: 00000246 ORIG_RAX: 000000000000011d
RAX: ffffffffffffffda RBX: 00007f0d8dc45fa0 RCX: 00007f0d8d9cce59
RDX: 0000000000000600 RSI: 0000000000000011 RDI: 0000000000000003
RBP: 00007f0d8da62d6f R08: 0000000000000000 R09: 0000000000000000
R10: 001800000007c000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f0d8dc45fac R14: 00007f0d8dc45fa0 R15: 00007f0d8dc45fa0
INFO: task syz.0.17:5942 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.17 state:D stack:27864 pid:5942 tgid:5942 ppid:5761 task_flags:0x400040 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5504 [inline]
__schedule+0x16dc/0x5500 kernel/sched/core.c:7228
__schedule_loop kernel/sched/core.c:7307 [inline]
rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7603
rt_mutex_slowlock_block kernel/locking/rtmutex.c:1670 [inline]
__rt_mutex_slowlock kernel/locking/rtmutex.c:1747 [inline]
__rt_mutex_slowlock_locked+0x1f84/0x25b0 kernel/locking/rtmutex.c:1787
rt_mutex_slowlock+0xbd/0x170 kernel/locking/rtmutex.c:1827
__rt_mutex_lock kernel/locking/rtmutex.c:1842 [inline]
rwbase_write_lock+0x14c/0x720 kernel/locking/rwbase_rt.c:251
inode_lock include/linux/fs.h:1029 [inline]
blkdev_fallocate+0x263/0x550 block/fops.c:907
vfs_fallocate+0x663/0x7f0 fs/open.c:338
ksys_fallocate fs/open.c:362 [inline]
__do_sys_fallocate fs/open.c:367 [inline]
__se_sys_fallocate fs/open.c:365 [inline]
__x64_sys_fallocate+0xbf/0x110 fs/open.c:365
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa5d160ce59
RSP: 002b:00007ffe3583fb28 EFLAGS: 00000246 ORIG_RAX: 000000000000011d
RAX: ffffffffffffffda RBX: 00007fa5d1885fa0 RCX: 00007fa5d160ce59
RDX: 0000000000000600 RSI: 0000000000000011 RDI: 0000000000000003
RBP: 00007fa5d16a2d6f R08: 0000000000000000 R09: 0000000000000000
R10: 001800000007c000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fa5d1885fac R14: 00007fa5d1885fa0 R15: 00007fa5d1885fa0
INFO: task syz.4.21:5944 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.21 state:D stack:27768 pid:5944 tgid:5944 ppid:5775 task_flags:0x400040 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5504 [inline]
__schedule+0x16dc/0x5500 kernel/sched/core.c:7228
__schedule_loop kernel/sched/core.c:7307 [inline]
rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7603
rt_mutex_slowlock_block kernel/locking/rtmutex.c:1670 [inline]
__rt_mutex_slowlock kernel/locking/rtmutex.c:1747 [inline]
__rt_mutex_slowlock_locked+0x1f84/0x25b0 kernel/locking/rtmutex.c:1787
rt_mutex_slowlock+0xbd/0x170 kernel/locking/rtmutex.c:1827
__rt_mutex_lock kernel/locking/rtmutex.c:1842 [inline]
rwbase_write_lock+0x14c/0x720 kernel/locking/rwbase_rt.c:251
inode_lock include/linux/fs.h:1029 [inline]
blkdev_fallocate+0x263/0x550 block/fops.c:907
vfs_fallocate+0x663/0x7f0 fs/open.c:338
ksys_fallocate fs/open.c:362 [inline]
__do_sys_fallocate fs/open.c:367 [inline]
__se_sys_fallocate fs/open.c:365 [inline]
__x64_sys_fallocate+0xbf/0x110 fs/open.c:365
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f78c0f5ce59
RSP: 002b:00007ffc7d020ac8 EFLAGS: 00000246 ORIG_RAX: 000000000000011d
RAX: ffffffffffffffda RBX: 00007f78c11d5fa0 RCX: 00007f78c0f5ce59
RDX: 0000000000000600 RSI: 0000000000000011 RDI: 0000000000000003
RBP: 00007f78c0ff2d6f R08: 0000000000000000 R09: 0000000000000000
R10: 001800000007c000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f78c11d5fac R14: 00007f78c11d5fa0 R15: 00007f78c11d5fa0
INFO: lockdep is turned off.
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 37 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Call Trace:
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline]
__sys_info lib/sys_info.c:157 [inline]
sys_info+0x135/0x170 lib/sys_info.c:165
check_hung_uninterruptible_tasks kernel/hung_task.c:353 [inline]
watchdog+0xfd7/0x1030 kernel/hung_task.c:561
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 17 Comm: pr/legacy Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:preempt_latency_start kernel/sched/core.c:5959 [inline]
RIP: 0010:preempt_count_add+0xb9/0x190 kernel/sched/core.c:5982
Code: 0d 00 85 c0 74 09 31 db 31 ff e8 52 af 0d 00 65 4c 8b 35 a2 af b5 10 49 81 c6 e8 15 00 00 4c 89 f0 48 c1 e8 03 42 80 3c 38 00 <74> 08 4c 89 f7 e8 bd ac 98 00 49 89 1e 5b 41 5e 41 5f e9 10 6c 88
RSP: 0018:ffffc900001679e8 EFLAGS: 00000246
RAX: 1ffff1100395ae5d RBX: ffffffff8b169a35 RCX: ffffffff99544500
RDX: 000000000000009e RSI: ffffffff8b877e00 RDI: ffffffff8b169a35
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffffff8b1699d0 R12: 1ffffffff331f9aa
R13: 00000000ffffffff R14: ffff88801cad72e8 R15: dffffc0000000000
FS: 0000000000000000(0000) GS:ffff888126390000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055887a3afde0 CR3: 00000000341d6000 CR4: 00000000003526f0
Call Trace:
delay_tsc+0x65/0xc0 arch/x86/lib/delay.c:79
udelay include/asm-generic/delay.h:62 [inline]
wait_for_lsr+0x14d/0x300 drivers/tty/serial/8250/8250_port.c:1979
serial8250_fifo_wait_for_lsr_thre drivers/tty/serial/8250/8250_port.c:3210 [inline]
serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3275 [inline]
serial8250_console_write+0x1232/0x1bd0 drivers/tty/serial/8250/8250_port.c:3360
console_emit_next_record kernel/printk/printk.c:3163 [inline]
console_flush_one_record+0x642/0xb50 kernel/printk/printk.c:3269
legacy_kthread_func+0x1b6/0x250 kernel/printk/printk.c:3712
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
final repro crashed as (corrupted=false):
INFO: task syz.1.18:5940 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.18 state:D stack:27864 pid:5940 tgid:5940 ppid:5769 task_flags:0x400040 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5504 [inline]
__schedule+0x16dc/0x5500 kernel/sched/core.c:7228
__schedule_loop kernel/sched/core.c:7307 [inline]
rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7603
rt_mutex_slowlock_block kernel/locking/rtmutex.c:1670 [inline]
__rt_mutex_slowlock kernel/locking/rtmutex.c:1747 [inline]
__rt_mutex_slowlock_locked+0x1f84/0x25b0 kernel/locking/rtmutex.c:1787
rt_mutex_slowlock+0xbd/0x170 kernel/locking/rtmutex.c:1827
__rt_mutex_lock kernel/locking/rtmutex.c:1842 [inline]
rwbase_write_lock+0x14c/0x720 kernel/locking/rwbase_rt.c:251
inode_lock include/linux/fs.h:1029 [inline]
blkdev_fallocate+0x263/0x550 block/fops.c:907
vfs_fallocate+0x663/0x7f0 fs/open.c:338
ksys_fallocate fs/open.c:362 [inline]
__do_sys_fallocate fs/open.c:367 [inline]
__se_sys_fallocate fs/open.c:365 [inline]
__x64_sys_fallocate+0xbf/0x110 fs/open.c:365
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ff2f04fce59
RSP: 002b:00007fffc0cd3c58 EFLAGS: 00000246 ORIG_RAX: 000000000000011d
RAX: ffffffffffffffda RBX: 00007ff2f0775fa0 RCX: 00007ff2f04fce59
RDX: 0000000000000600 RSI: 0000000000000011 RDI: 0000000000000003
RBP: 00007ff2f0592d6f R08: 0000000000000000 R09: 0000000000000000
R10: 001800000007c000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ff2f0775fac R14: 00007ff2f0775fa0 R15: 00007ff2f0775fa0
INFO: task syz.3.20:5941 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.20 state:D stack:27864 pid:5941 tgid:5941 ppid:5772 task_flags:0x400040 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5504 [inline]
__schedule+0x16dc/0x5500 kernel/sched/core.c:7228
__schedule_loop kernel/sched/core.c:7307 [inline]
rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7603
rt_mutex_slowlock_block kernel/locking/rtmutex.c:1670 [inline]
__rt_mutex_slowlock kernel/locking/rtmutex.c:1747 [inline]
__rt_mutex_slowlock_locked+0x1f84/0x25b0 kernel/locking/rtmutex.c:1787
rt_mutex_slowlock+0xbd/0x170 kernel/locking/rtmutex.c:1827
__rt_mutex_lock kernel/locking/rtmutex.c:1842 [inline]
rwbase_write_lock+0x14c/0x720 kernel/locking/rwbase_rt.c:251
inode_lock include/linux/fs.h:1029 [inline]
blkdev_fallocate+0x263/0x550 block/fops.c:907
vfs_fallocate+0x663/0x7f0 fs/open.c:338
ksys_fallocate fs/open.c:362 [inline]
__do_sys_fallocate fs/open.c:367 [inline]
__se_sys_fallocate fs/open.c:365 [inline]
__x64_sys_fallocate+0xbf/0x110 fs/open.c:365
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f0d8d9cce59
RSP: 002b:00007ffd3c4ebee8 EFLAGS: 00000246 ORIG_RAX: 000000000000011d
RAX: ffffffffffffffda RBX: 00007f0d8dc45fa0 RCX: 00007f0d8d9cce59
RDX: 0000000000000600 RSI: 0000000000000011 RDI: 0000000000000003
RBP: 00007f0d8da62d6f R08: 0000000000000000 R09: 0000000000000000
R10: 001800000007c000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f0d8dc45fac R14: 00007f0d8dc45fa0 R15: 00007f0d8dc45fa0
INFO: task syz.0.17:5942 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.17 state:D stack:27864 pid:5942 tgid:5942 ppid:5761 task_flags:0x400040 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5504 [inline]
__schedule+0x16dc/0x5500 kernel/sched/core.c:7228
__schedule_loop kernel/sched/core.c:7307 [inline]
rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7603
rt_mutex_slowlock_block kernel/locking/rtmutex.c:1670 [inline]
__rt_mutex_slowlock kernel/locking/rtmutex.c:1747 [inline]
__rt_mutex_slowlock_locked+0x1f84/0x25b0 kernel/locking/rtmutex.c:1787
rt_mutex_slowlock+0xbd/0x170 kernel/locking/rtmutex.c:1827
__rt_mutex_lock kernel/locking/rtmutex.c:1842 [inline]
rwbase_write_lock+0x14c/0x720 kernel/locking/rwbase_rt.c:251
inode_lock include/linux/fs.h:1029 [inline]
blkdev_fallocate+0x263/0x550 block/fops.c:907
vfs_fallocate+0x663/0x7f0 fs/open.c:338
ksys_fallocate fs/open.c:362 [inline]
__do_sys_fallocate fs/open.c:367 [inline]
__se_sys_fallocate fs/open.c:365 [inline]
__x64_sys_fallocate+0xbf/0x110 fs/open.c:365
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa5d160ce59
RSP: 002b:00007ffe3583fb28 EFLAGS: 00000246 ORIG_RAX: 000000000000011d
RAX: ffffffffffffffda RBX: 00007fa5d1885fa0 RCX: 00007fa5d160ce59
RDX: 0000000000000600 RSI: 0000000000000011 RDI: 0000000000000003
RBP: 00007fa5d16a2d6f R08: 0000000000000000 R09: 0000000000000000
R10: 001800000007c000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fa5d1885fac R14: 00007fa5d1885fa0 R15: 00007fa5d1885fa0
INFO: task syz.4.21:5944 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.21 state:D stack:27768 pid:5944 tgid:5944 ppid:5775 task_flags:0x400040 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5504 [inline]
__schedule+0x16dc/0x5500 kernel/sched/core.c:7228
__schedule_loop kernel/sched/core.c:7307 [inline]
rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7603
rt_mutex_slowlock_block kernel/locking/rtmutex.c:1670 [inline]
__rt_mutex_slowlock kernel/locking/rtmutex.c:1747 [inline]
__rt_mutex_slowlock_locked+0x1f84/0x25b0 kernel/locking/rtmutex.c:1787
rt_mutex_slowlock+0xbd/0x170 kernel/locking/rtmutex.c:1827
__rt_mutex_lock kernel/locking/rtmutex.c:1842 [inline]
rwbase_write_lock+0x14c/0x720 kernel/locking/rwbase_rt.c:251
inode_lock include/linux/fs.h:1029 [inline]
blkdev_fallocate+0x263/0x550 block/fops.c:907
vfs_fallocate+0x663/0x7f0 fs/open.c:338
ksys_fallocate fs/open.c:362 [inline]
__do_sys_fallocate fs/open.c:367 [inline]
__se_sys_fallocate fs/open.c:365 [inline]
__x64_sys_fallocate+0xbf/0x110 fs/open.c:365
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f78c0f5ce59
RSP: 002b:00007ffc7d020ac8 EFLAGS: 00000246 ORIG_RAX: 000000000000011d
RAX: ffffffffffffffda RBX: 00007f78c11d5fa0 RCX: 00007f78c0f5ce59
RDX: 0000000000000600 RSI: 0000000000000011 RDI: 0000000000000003
RBP: 00007f78c0ff2d6f R08: 0000000000000000 R09: 0000000000000000
R10: 001800000007c000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f78c11d5fac R14: 00007f78c11d5fa0 R15: 00007f78c11d5fa0
INFO: lockdep is turned off.
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 37 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Call Trace:
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline]
__sys_info lib/sys_info.c:157 [inline]
sys_info+0x135/0x170 lib/sys_info.c:165
check_hung_uninterruptible_tasks kernel/hung_task.c:353 [inline]
watchdog+0xfd7/0x1030 kernel/hung_task.c:561
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 17 Comm: pr/legacy Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:preempt_latency_start kernel/sched/core.c:5959 [inline]
RIP: 0010:preempt_count_add+0xb9/0x190 kernel/sched/core.c:5982
Code: 0d 00 85 c0 74 09 31 db 31 ff e8 52 af 0d 00 65 4c 8b 35 a2 af b5 10 49 81 c6 e8 15 00 00 4c 89 f0 48 c1 e8 03 42 80 3c 38 00 <74> 08 4c 89 f7 e8 bd ac 98 00 49 89 1e 5b 41 5e 41 5f e9 10 6c 88
RSP: 0018:ffffc900001679e8 EFLAGS: 00000246
RAX: 1ffff1100395ae5d RBX: ffffffff8b169a35 RCX: ffffffff99544500
RDX: 000000000000009e RSI: ffffffff8b877e00 RDI: ffffffff8b169a35
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffffff8b1699d0 R12: 1ffffffff331f9aa
R13: 00000000ffffffff R14: ffff88801cad72e8 R15: dffffc0000000000
FS: 0000000000000000(0000) GS:ffff888126390000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055887a3afde0 CR3: 00000000341d6000 CR4: 00000000003526f0
Call Trace:
delay_tsc+0x65/0xc0 arch/x86/lib/delay.c:79
udelay include/asm-generic/delay.h:62 [inline]
wait_for_lsr+0x14d/0x300 drivers/tty/serial/8250/8250_port.c:1979
serial8250_fifo_wait_for_lsr_thre drivers/tty/serial/8250/8250_port.c:3210 [inline]
serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3275 [inline]
serial8250_console_write+0x1232/0x1bd0 drivers/tty/serial/8250/8250_port.c:3360
console_emit_next_record kernel/printk/printk.c:3163 [inline]
console_flush_one_record+0x642/0xb50 kernel/printk/printk.c:3269
legacy_kthread_func+0x1b6/0x250 kernel/printk/printk.c:3712
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245