Extracting prog: 7m55.897033917s
Minimizing prog: 37m31.347477821s
Simplifying prog options: 8m21.492142061s
Extracting C: 4m8.40638182s
Simplifying C: 0s


extracting reproducer from 1 programs
testing a last program of every proc
single: executing 1 programs separately with timeout 30s
testing program (duration=30s, {Threaded:true Repeat:true RepeatTimes:0 Procs:6 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}}): socket-bpf$BPF_BTF_LOAD-ioctl$sock_SIOCBRDELBR
detailed listing:
executing program 0:
r0 = socket(0xa, 0x3, 0x4)
bpf$BPF_BTF_LOAD(0x12, &(0x7f0000000280)={&(0x7f0000000000)={{0xeb9f, 0x1, 0x0, 0x18, 0x0, 0x1c, 0x1c, 0x2, [@int={0x0, 0x0, 0x0, 0x1, 0x5}, @union={0x0, 0x0, 0x0, 0x9}]}}, 0x0, 0x36}, 0x20)
ioctl$sock_SIOCBRDELBR(r0, 0x89a2, &(0x7f0000000000)='bridge0\x00')

program did not crash
single: failed to extract reproducer
single: executing 1 programs separately with timeout 1m40s
testing program (duration=1m40s, {Threaded:true Repeat:true RepeatTimes:0 Procs:6 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}}): socket-bpf$BPF_BTF_LOAD-ioctl$sock_SIOCBRDELBR
detailed listing:
executing program 0:
r0 = socket(0xa, 0x3, 0x4)
bpf$BPF_BTF_LOAD(0x12, &(0x7f0000000280)={&(0x7f0000000000)={{0xeb9f, 0x1, 0x0, 0x18, 0x0, 0x1c, 0x1c, 0x2, [@int={0x0, 0x0, 0x0, 0x1, 0x5}, @union={0x0, 0x0, 0x0, 0x9}]}}, 0x0, 0x36}, 0x20)
ioctl$sock_SIOCBRDELBR(r0, 0x89a2, &(0x7f0000000000)='bridge0\x00')

program did not crash
single: failed to extract reproducer
single: executing 1 programs separately with timeout 6m0s
testing program (duration=6m0s, {Threaded:true Repeat:true RepeatTimes:0 Procs:6 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}}): socket-bpf$BPF_BTF_LOAD-ioctl$sock_SIOCBRDELBR
detailed listing:
executing program 0:
r0 = socket(0xa, 0x3, 0x4)
bpf$BPF_BTF_LOAD(0x12, &(0x7f0000000280)={&(0x7f0000000000)={{0xeb9f, 0x1, 0x0, 0x18, 0x0, 0x1c, 0x1c, 0x2, [@int={0x0, 0x0, 0x0, 0x1, 0x5}, @union={0x0, 0x0, 0x0, 0x9}]}}, 0x0, 0x36}, 0x20)
ioctl$sock_SIOCBRDELBR(r0, 0x89a2, &(0x7f0000000000)='bridge0\x00')

program crashed: INFO: task hung in rtnl_newlink
single: successfully extracted reproducer
found reproducer with 3 syscalls
minimizing guilty program
testing program (duration=6m5.844574449s, {Threaded:true Repeat:true RepeatTimes:0 Procs:6 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}}): socket-bpf$BPF_BTF_LOAD
detailed listing:
executing program 0:
socket(0xa, 0x3, 0x4)
bpf$BPF_BTF_LOAD(0x12, &(0x7f0000000280)={&(0x7f0000000000)={{0xeb9f, 0x1, 0x0, 0x18, 0x0, 0x1c, 0x1c, 0x2, [@int={0x0, 0x0, 0x0, 0x1, 0x5}, @union={0x0, 0x0, 0x0, 0x9}]}}, 0x0, 0x36}, 0x20)

program did not crash
testing program (duration=6m5.844574449s, {Threaded:true Repeat:true RepeatTimes:0 Procs:6 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}}): socket-ioctl$sock_SIOCBRDELBR
detailed listing:
executing program 0:
r0 = socket(0xa, 0x3, 0x4)
ioctl$sock_SIOCBRDELBR(r0, 0x89a2, &(0x7f0000000000)='bridge0\x00')

program did not crash
testing program (duration=6m5.844574449s, {Threaded:true Repeat:true RepeatTimes:0 Procs:6 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}}): bpf$BPF_BTF_LOAD-ioctl$sock_SIOCBRDELBR
detailed listing:
executing program 0:
bpf$BPF_BTF_LOAD(0x12, &(0x7f0000000280)={&(0x7f0000000000)={{0xeb9f, 0x1, 0x0, 0x18, 0x0, 0x1c, 0x1c, 0x2, [@int={0x0, 0x0, 0x0, 0x1, 0x5}, @union={0x0, 0x0, 0x0, 0x9}]}}, 0x0, 0x36}, 0x20)
ioctl$sock_SIOCBRDELBR(0xffffffffffffffff, 0x89a2, &(0x7f0000000000)='bridge0\x00')

program did not crash
testing program (duration=6m5.844574449s, {Threaded:true Repeat:true RepeatTimes:0 Procs:6 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}}): socket-bpf$BPF_BTF_LOAD-ioctl$sock_SIOCBRDELBR
detailed listing:
executing program 0:
r0 = socket(0xa, 0x3, 0x4)
bpf$BPF_BTF_LOAD(0x12, 0x0, 0x0)
ioctl$sock_SIOCBRDELBR(r0, 0x89a2, &(0x7f0000000000)='bridge0\x00')

program did not crash
testing program (duration=6m5.844574449s, {Threaded:true Repeat:true RepeatTimes:0 Procs:6 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}}): socket-bpf$BPF_BTF_LOAD-ioctl$sock_SIOCBRDELBR
detailed listing:
executing program 0:
r0 = socket(0xa, 0x3, 0x4)
bpf$BPF_BTF_LOAD(0x12, &(0x7f0000000280)={0x0, 0x0}, 0x28)
ioctl$sock_SIOCBRDELBR(r0, 0x89a2, &(0x7f0000000000)='bridge0\x00')

program did not crash
testing program (duration=6m5.844574449s, {Threaded:true Repeat:true RepeatTimes:0 Procs:6 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}}): socket-bpf$BPF_BTF_LOAD-ioctl$sock_SIOCBRDELBR
detailed listing:
executing program 0:
r0 = socket(0xa, 0x3, 0x4)
bpf$BPF_BTF_LOAD(0x12, &(0x7f0000000280)={&(0x7f0000000000)={{0xeb9f, 0x1, 0x0, 0x18, 0x0, 0x1c, 0x1c, 0x2, [@int={0x0, 0x0, 0x0, 0x1, 0x5}, @union={0x0, 0x0, 0x0, 0x9}]}}, 0x0, 0x36}, 0x20)
ioctl$sock_SIOCBRDELBR(r0, 0x89a2, 0x0)

program did not crash
extracting C reproducer
testing compiled C program (duration=6m5.844574449s, {Threaded:true Repeat:true RepeatTimes:0 Procs:6 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}}): socket-bpf$BPF_BTF_LOAD-ioctl$sock_SIOCBRDELBR
program crashed: INFO: task hung in addrconf_dad_work
a never seen crash title: INFO: task hung in addrconf_dad_work, ignore
simplifying guilty program options
testing program (duration=6m5.844574449s, {Threaded:false Repeat:true RepeatTimes:0 Procs:6 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}}): socket-bpf$BPF_BTF_LOAD-ioctl$sock_SIOCBRDELBR
detailed listing:
executing program 0:
r0 = socket(0xa, 0x3, 0x4)
bpf$BPF_BTF_LOAD(0x12, &(0x7f0000000280)={&(0x7f0000000000)={{0xeb9f, 0x1, 0x0, 0x18, 0x0, 0x1c, 0x1c, 0x2, [@int={0x0, 0x0, 0x0, 0x1, 0x5}, @union={0x0, 0x0, 0x0, 0x9}]}}, 0x0, 0x36}, 0x20)
ioctl$sock_SIOCBRDELBR(r0, 0x89a2, &(0x7f0000000000)='bridge0\x00')

program crashed: INFO: task hung in devinet_ioctl
a never seen crash title: INFO: task hung in devinet_ioctl, ignore
testing program (duration=6m5.844574449s, {Threaded:true 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}}): socket-bpf$BPF_BTF_LOAD-ioctl$sock_SIOCBRDELBR
detailed listing:
executing program 0:
r0 = socket(0xa, 0x3, 0x4)
bpf$BPF_BTF_LOAD(0x12, &(0x7f0000000280)={&(0x7f0000000000)={{0xeb9f, 0x1, 0x0, 0x18, 0x0, 0x1c, 0x1c, 0x2, [@int={0x0, 0x0, 0x0, 0x1, 0x5}, @union={0x0, 0x0, 0x0, 0x9}]}}, 0x0, 0x36}, 0x20)
ioctl$sock_SIOCBRDELBR(r0, 0x89a2, &(0x7f0000000000)='bridge0\x00')

program crashed: INFO: task hung in inet6_rtm_newaddr
a never seen crash title: INFO: task hung in inet6_rtm_newaddr, ignore
testing program (duration=6m5.844574449s, {Threaded:true Repeat:true RepeatTimes:0 Procs:6 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}}): socket-bpf$BPF_BTF_LOAD-ioctl$sock_SIOCBRDELBR
detailed listing:
executing program 0:
r0 = socket(0xa, 0x3, 0x4)
bpf$BPF_BTF_LOAD(0x12, &(0x7f0000000280)={&(0x7f0000000000)={{0xeb9f, 0x1, 0x0, 0x18, 0x0, 0x1c, 0x1c, 0x2, [@int={0x0, 0x0, 0x0, 0x1, 0x5}, @union={0x0, 0x0, 0x0, 0x9}]}}, 0x0, 0x36}, 0x20)
ioctl$sock_SIOCBRDELBR(r0, 0x89a2, &(0x7f0000000000)='bridge0\x00')

program crashed: INFO: task hung in tun_chr_close
validation run: crashed=true
testing program (duration=6m5.844574449s, {Threaded:true Repeat:true RepeatTimes:0 Procs:6 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}}): socket-bpf$BPF_BTF_LOAD-ioctl$sock_SIOCBRDELBR
detailed listing:
executing program 0:
r0 = socket(0xa, 0x3, 0x4)
bpf$BPF_BTF_LOAD(0x12, &(0x7f0000000280)={&(0x7f0000000000)={{0xeb9f, 0x1, 0x0, 0x18, 0x0, 0x1c, 0x1c, 0x2, [@int={0x0, 0x0, 0x0, 0x1, 0x5}, @union={0x0, 0x0, 0x0, 0x9}]}}, 0x0, 0x36}, 0x20)
ioctl$sock_SIOCBRDELBR(r0, 0x89a2, &(0x7f0000000000)='bridge0\x00')

program crashed: INFO: task hung in inet6_rtm_newaddr
validation run: crashed=true
testing program (duration=6m5.844574449s, {Threaded:true Repeat:true RepeatTimes:0 Procs:6 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}}): socket-bpf$BPF_BTF_LOAD-ioctl$sock_SIOCBRDELBR
detailed listing:
executing program 0:
r0 = socket(0xa, 0x3, 0x4)
bpf$BPF_BTF_LOAD(0x12, &(0x7f0000000280)={&(0x7f0000000000)={{0xeb9f, 0x1, 0x0, 0x18, 0x0, 0x1c, 0x1c, 0x2, [@int={0x0, 0x0, 0x0, 0x1, 0x5}, @union={0x0, 0x0, 0x0, 0x9}]}}, 0x0, 0x36}, 0x20)
ioctl$sock_SIOCBRDELBR(r0, 0x89a2, &(0x7f0000000000)='bridge0\x00')

program crashed: INFO: task hung in addrconf_dad_work
validation run: crashed=true
reproducing took 1h10m59.026256618s
repro crashed as (corrupted=false):
INFO: task kworker/u4:6:1039 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:6    state:D stack:23160 pid:1039  tgid:1039  ppid:2      task_flags:0x4208060 flags:0x00080000
Workqueue: ipv6_addrconf addrconf_dad_work
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5325 [inline]
 __schedule+0x1798/0x4cc0 kernel/sched/core.c:6929
 __schedule_loop kernel/sched/core.c:7011 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:7026
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7083
 __mutex_lock_common kernel/locking/mutex.c:676 [inline]
 __mutex_lock+0x7e6/0x1350 kernel/locking/mutex.c:760
 rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
 addrconf_dad_work+0x112/0x14b0 net/ipv6/addrconf.c:4194
 process_one_work kernel/workqueue.c:3263 [inline]
 process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3346
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
INFO: task kworker/u4:7:1042 blocked for more than 149 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:7    state:D stack:24552 pid:1042  tgid:1042  ppid:2      task_flags:0x4208060 flags:0x00080000
Workqueue: events_unbound linkwatch_event
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5325 [inline]
 __schedule+0x1798/0x4cc0 kernel/sched/core.c:6929
 __schedule_loop kernel/sched/core.c:7011 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:7026
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7083
 __mutex_lock_common kernel/locking/mutex.c:676 [inline]
 __mutex_lock+0x7e6/0x1350 kernel/locking/mutex.c:760
 linkwatch_event+0xe/0x60 net/core/link_watch.c:303
 process_one_work kernel/workqueue.c:3263 [inline]
 process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3346
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158

final repro crashed as (corrupted=false):
INFO: task kworker/u4:6:1039 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:6    state:D stack:23160 pid:1039  tgid:1039  ppid:2      task_flags:0x4208060 flags:0x00080000
Workqueue: ipv6_addrconf addrconf_dad_work
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5325 [inline]
 __schedule+0x1798/0x4cc0 kernel/sched/core.c:6929
 __schedule_loop kernel/sched/core.c:7011 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:7026
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7083
 __mutex_lock_common kernel/locking/mutex.c:676 [inline]
 __mutex_lock+0x7e6/0x1350 kernel/locking/mutex.c:760
 rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
 addrconf_dad_work+0x112/0x14b0 net/ipv6/addrconf.c:4194
 process_one_work kernel/workqueue.c:3263 [inline]
 process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3346
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
INFO: task kworker/u4:7:1042 blocked for more than 149 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:7    state:D stack:24552 pid:1042  tgid:1042  ppid:2      task_flags:0x4208060 flags:0x00080000
Workqueue: events_unbound linkwatch_event
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5325 [inline]
 __schedule+0x1798/0x4cc0 kernel/sched/core.c:6929
 __schedule_loop kernel/sched/core.c:7011 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:7026
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7083
 __mutex_lock_common kernel/locking/mutex.c:676 [inline]
 __mutex_lock+0x7e6/0x1350 kernel/locking/mutex.c:760
 linkwatch_event+0xe/0x60 net/core/link_watch.c:303
 process_one_work kernel/workqueue.c:3263 [inline]
 process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3346
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158