syzbot


INFO: task hung in cgroup_can_fork (2)

Status: upstream: reported C repro on 2025/09/11 03:23
Bug presence: origin:upstream
[Documentation on labels]
Reported-by: syzbot+6b5cbd79e0efb0612e59@syzkaller.appspotmail.com
First crash: 128d, last: 5d09h
Bug presence (1)
Date Name Commit Repro Result
2025/09/25 upstream (ToT) bf40f4b87761 C [report] INFO: task hung in exit_mmap
Similar bugs (5)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in cgroup_can_fork (2) cgroups 1 5 483d 563d 0/29 auto-obsoleted due to no activity on 2024/12/20 05:36
linux-6.1 INFO: task hung in cgroup_can_fork 1 1 451d 451d 0/3 auto-obsoleted due to no activity on 2025/01/30 16:24
linux-6.1 INFO: task hung in cgroup_can_fork (2) origin:upstream 1 C inconclusive 12 7d00h 115d 0/3 upstream: reported C repro on 2025/09/23 15:45
linux-5.15 INFO: task hung in cgroup_can_fork 1 1 469d 469d 0/3 auto-obsoleted due to no activity on 2025/01/13 02:23
upstream INFO: task hung in cgroup_can_fork cgroups 1 C error error 6 1466d 1486d 0/29 auto-obsoleted due to no activity on 2023/09/02 21:24
Last patch testing requests (10)
Created Duration User Patch Repo Result
2025/12/30 00:11 18m retest repro linux-5.15.y report log
2025/12/30 00:11 18m retest repro linux-5.15.y report log
2025/12/30 00:11 18m retest repro linux-5.15.y report log
2025/12/30 00:11 18m retest repro linux-5.15.y report log
2025/12/30 00:11 18m retest repro linux-5.15.y report log
2025/12/29 09:03 12m retest repro linux-5.15.y report log
2025/12/29 09:03 16m retest repro linux-5.15.y report log
2025/12/29 09:03 12m retest repro linux-5.15.y report log
2025/12/29 09:03 13m retest repro linux-5.15.y report log
2025/12/29 09:03 12m retest repro linux-5.15.y report log

Sample crash report:
INFO: task kthreadd:2 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kthreadd        state:D stack:26336 pid:    2 ppid:     0 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11bb/0x4390 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 percpu_rwsem_wait+0x2d8/0x310 kernel/locking/percpu-rwsem.c:160
 __percpu_down_read+0xc9/0x100 kernel/locking/percpu-rwsem.c:174
 percpu_down_read include/linux/percpu-rwsem.h:65 [inline]
 cgroup_threadgroup_change_begin include/linux/cgroup-defs.h:724 [inline]
 cgroup_css_set_fork kernel/cgroup/cgroup.c:6225 [inline]
 cgroup_can_fork+0xc94/0xda0 kernel/cgroup/cgroup.c:6343
 copy_process+0x2290/0x3e00 kernel/fork.c:2382
 kernel_clone+0x219/0x930 kernel/fork.c:2679
 kernel_thread+0xc8/0x120 kernel/fork.c:2731
 create_kthread kernel/kthread.c:357 [inline]
 kthreadd+0x520/0x6f0 kernel/kthread.c:703
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
INFO: task kworker/1:1:23 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/1:1     state:D stack:24264 pid:   23 ppid:     2 flags:0x00004000
Workqueue: ipv6_addrconf addrconf_dad_work
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11bb/0x4390 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6537
 __mutex_lock_common+0xc71/0x2390 kernel/locking/mutex.c:669
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
 addrconf_dad_work+0xc4/0x1520 net/ipv6/addrconf.c:4110
 process_one_work+0x863/0x1000 kernel/workqueue.c:2310
 worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
INFO: task kworker/u4:3:155 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:3    state:D stack:22944 pid:  155 ppid:     2 flags:0x00004000
Workqueue: netns cleanup_net
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11bb/0x4390 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6537
 __mutex_lock_common+0xc71/0x2390 kernel/locking/mutex.c:669
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
 fib6_rules_net_exit+0xe/0x50 net/ipv6/fib6_rules.c:506
 ops_exit_list net/core/net_namespace.c:172 [inline]
 cleanup_net+0x6f0/0xb80 net/core/net_namespace.c:635
 process_one_work+0x863/0x1000 kernel/workqueue.c:2310
 worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
INFO: task kworker/1:2:1107 blocked for more than 144 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/1:2     state:D stack:25280 pid: 1107 ppid:     2 flags:0x00004000
Workqueue: events request_firmware_work_func
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11bb/0x4390 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6537
 __mutex_lock_common+0xc71/0x2390 kernel/locking/mutex.c:669
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
 regdb_fw_cb+0x79/0x1b0 net/wireless/reg.c:1053
 request_firmware_work_func+0xfb/0x1b0 drivers/base/firmware_loader/main.c:1129
 process_one_work+0x863/0x1000 kernel/workqueue.c:2310
 worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
INFO: task kworker/0:2:1110 blocked for more than 144 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/0:2     state:D stack:24840 pid: 1110 ppid:     2 flags:0x00004000
Workqueue: ipv6_addrconf addrconf_dad_work
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11bb/0x4390 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6537
 __mutex_lock_common+0xc71/0x2390 kernel/locking/mutex.c:669
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
 addrconf_dad_work+0xc4/0x1520 net/ipv6/addrconf.c:4110
 process_one_work+0x863/0x1000 kernel/workqueue.c:2310
 worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
INFO: task udevd:3560 blocked for more than 144 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:udevd           state:D stack:24264 pid: 3560 ppid:     1 flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11bb/0x4390 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6537
 __mutex_lock_common+0xc71/0x2390 kernel/locking/mutex.c:669
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
 device_lock include/linux/device.h:764 [inline]
 uevent_show+0x17a/0x330 drivers/base/core.c:2408
 dev_attr_show+0x50/0xb0 drivers/base/core.c:2110
 sysfs_kf_seq_show+0x316/0x4c0 fs/sysfs/file.c:61
 seq_read_iter+0x49b/0xd50 fs/seq_file.c:230
 call_read_iter include/linux/fs.h:2167 [inline]
 new_sync_read fs/read_write.c:404 [inline]
 vfs_read+0x725/0xcf0 fs/read_write.c:485
 ksys_read+0x14d/0x250 fs/read_write.c:623
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f6905d13407
RSP: 002b:00007ffe16b82bf0 EFLAGS: 00000202 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007f6905c25880 RCX: 00007f6905d13407
RDX: 0000000000001000 RSI: 000055c986db3730 RDI: 000000000000000c
RBP: 00007f6905e5bff0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 000000000000000a
R13: 00007f6905e5bea0 R14: 0000000000000000 R15: 000055c986d917a0
 </TASK>
INFO: task syz-executor:4300 blocked for more than 144 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:21224 pid: 4300 ppid:  4294 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11bb/0x4390 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6537
 __mutex_lock_common+0xc71/0x2390 kernel/locking/mutex.c:669
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
 nsim_init_netdevsim drivers/net/netdevsim/netdev.c:310 [inline]
 nsim_create+0x2ef/0x3e0 drivers/net/netdevsim/netdev.c:365
 __nsim_dev_port_add+0x5c7/0x980 drivers/net/netdevsim/dev.c:1312
 nsim_dev_port_add_all+0x37/0x100 drivers/net/netdevsim/dev.c:1372
 nsim_dev_probe+0x754/0x9c0 drivers/net/netdevsim/dev.c:1513
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x284/0xc80 drivers/base/dd.c:595
 __driver_probe_device+0x18c/0x330 drivers/base/dd.c:755
 driver_probe_device+0x4f/0x420 drivers/base/dd.c:785
 __device_attach_driver+0x2b0/0x500 drivers/base/dd.c:907
 bus_for_each_drv+0x175/0x200 drivers/base/bus.c:429
 __device_attach+0x29b/0x460 drivers/base/dd.c:979
 bus_probe_device+0xbc/0x1e0 drivers/base/bus.c:489
 device_add+0xa00/0xfb0 drivers/base/core.c:3412
 nsim_bus_dev_new drivers/net/netdevsim/bus.c:435 [inline]
 new_device_store+0x3d8/0x740 drivers/net/netdevsim/bus.c:302
 kernfs_fop_write_iter+0x379/0x4c0 fs/kernfs/file.c:296
 call_write_iter include/linux/fs.h:2173 [inline]
 new_sync_write fs/read_write.c:507 [inline]
 vfs_write+0x712/0xd00 fs/read_write.c:594
 ksys_write+0x14d/0x250 fs/read_write.c:647
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f2cb26131ff
RSP: 002b:00007ffcfdf99830 EFLAGS: 00000293 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 00007f2cb26131ff
RDX: 0000000000000003 RSI: 00007ffcfdf99880 RDI: 0000000000000005
RBP: 00007f2cb269a2ef R08: 0000000000000000 R09: 00007ffcfdf99687
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000003
R13: 00007ffcfdf99880 R14: 00007f2cb3399620 R15: 0000000000000003
 </TASK>
INFO: task syz-executor:4308 blocked for more than 145 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:21792 pid: 4308 ppid:  4296 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11bb/0x4390 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 rwsem_down_write_slowpath+0xc46/0x11f0 kernel/locking/rwsem.c:1165
 mmap_write_lock include/linux/mmap_lock.h:71 [inline]
 mpol_rebind_mm+0x33/0x2c0 mm/mempolicy.c:381
 cpuset_attach+0x330/0x5f0 kernel/cgroup/cpuset.c:2376
 cgroup_migrate_execute+0x7eb/0x1010 kernel/cgroup/cgroup.c:2597
 cgroup_attach_task+0x562/0x7e0 kernel/cgroup/cgroup.c:2892
 __cgroup1_procs_write+0x2e5/0x3f0 kernel/cgroup/cgroup-v1.c:527
 cgroup_file_write+0x2f7/0x630 kernel/cgroup/cgroup.c:3966
 kernfs_fop_write_iter+0x379/0x4c0 fs/kernfs/file.c:296
 call_write_iter include/linux/fs.h:2173 [inline]
 new_sync_write fs/read_write.c:507 [inline]
 vfs_write+0x712/0xd00 fs/read_write.c:594
 ksys_write+0x14d/0x250 fs/read_write.c:647
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fd63911a1ff
RSP: 002b:00007ffcca21df90 EFLAGS: 00000293 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007fd63911a1ff
RDX: 0000000000000001 RSI: 00007ffcca21dfe0 RDI: 0000000000000003
RBP: 00007ffcca21e550 R08: 0000000000000000 R09: 00007ffcca21dde7
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000001
R13: 00007ffcca21dfe0 R14: 00007ffcca21e510 R15: 00007ffcca21e550
 </TASK>
INFO: task syz-executor:4313 blocked for more than 145 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:21832 pid: 4313 ppid:  4304 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11bb/0x4390 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6537
 __mutex_lock_common+0xc71/0x2390 kernel/locking/mutex.c:669
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
 rtnl_lock net/core/rtnetlink.c:72 [inline]
 rtnetlink_rcv_msg+0x7a5/0xe90 net/core/rtnetlink.c:5681
 netlink_rcv_skb+0x1e0/0x430 net/netlink/af_netlink.c:2507
 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
 netlink_unicast+0x774/0x920 net/netlink/af_netlink.c:1344
 netlink_sendmsg+0x8ab/0xbc0 net/netlink/af_netlink.c:1918
 sock_sendmsg_nosec net/socket.c:706 [inline]
 __sock_sendmsg net/socket.c:718 [inline]
 __sys_sendto+0x423/0x580 net/socket.c:2073
 __do_sys_sendto net/socket.c:2085 [inline]
 __se_sys_sendto net/socket.c:2081 [inline]
 __x64_sys_sendto+0xda/0xf0 net/socket.c:2081
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f923dd655dc
RSP: 002b:00007ffcc260cf40 EFLAGS: 00000293 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007f923eae75c0 RCX: 00007f923dd655dc
RDX: 0000000000000030 RSI: 00007f923eae7610 RDI: 0000000000000006
RBP: 0000000000000000 R08: 00007ffcc260cf94 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000006
R13: 0000000000000000 R14: 00007f923eae7610 R15: 0000000000000000
 </TASK>

Showing all locks held in the system:
1 lock held by kthreadd/2:
 #0: ffffffff8c1421b0 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: copy_process+0x2290/0x3e00 kernel/fork.c:2382
3 locks held by kworker/1:1/23:
 #0: ffff88802b53f538 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
 #1: ffffc90000ddfd00 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
 #2: ffffffff8d232788 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_dad_work+0xc4/0x1520 net/ipv6/addrconf.c:4110
1 lock held by khungtaskd/27:
 #0: ffffffff8c11c720 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
4 locks held by kworker/u4:3/155:
 #0: ffff8880169cd938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
 #1: ffffc90002047d00 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
 #2: ffffffff8d226b10 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x132/0xb80 net/core/net_namespace.c:589
 #3: ffffffff8d232788 (rtnl_mutex){+.+.}-{3:3}, at: fib6_rules_net_exit+0xe/0x50 net/ipv6/fib6_rules.c:506
3 locks held by kworker/1:2/1107:
 #0: ffff888016870938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
 #1: ffffc90004527d00 ((work_completion)(&fw_work->work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
 #2: ffffffff8d232788 (rtnl_mutex){+.+.}-{3:3}, at: regdb_fw_cb+0x79/0x1b0 net/wireless/reg.c:1053
3 locks held by kworker/0:2/1110:
 #0: ffff88802b53f538 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
 #1: ffffc90004547d00 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
 #2: ffffffff8d232788 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_dad_work+0xc4/0x1520 net/ipv6/addrconf.c:4110
4 locks held by udevd/3560:
 #0: ffff88807d4c6668 (&p->lock){+.+.}-{3:3}, at: seq_read_iter+0xad/0xd50 fs/seq_file.c:182
 #1: ffff8880794f2c88 (&of->mutex){+.+.}-{3:3}, at: kernfs_seq_start+0x51/0x3c0 fs/kernfs/file.c:112
 #2: ffff888073410660 (kn->active#32){++++}-{0:0}, at: kernfs_seq_start+0x71/0x3c0 fs/kernfs/file.c:113
 #3: ffff888059b81178 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:764 [inline]
 #3: ffff888059b81178 (&dev->mutex){....}-{3:3}, at: uevent_show+0x17a/0x330 drivers/base/core.c:2408
1 lock held by dhcpcd/3853:
 #0: ffffffff8c1421b0 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: copy_process+0x2290/0x3e00 kernel/fork.c:2382
2 locks held by getty/3945:
 #0: ffff88802cab2098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
 #1: ffffc900025e62e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x5ba/0x1a30 drivers/tty/n_tty.c:2158
2 locks held by kworker/u4:5/4249:
1 lock held by syz-executor/4292:
 #0: ffffffff8c1421b0 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: do_exit+0x256/0x20a0 kernel/exit.c:830
2 locks held by syz-executor/4297:
 #0: ffffffff8c1a68b0 (dup_mmap_sem){.+.+}-{0:0}, at: dup_mmap kernel/fork.c:503 [inline]
 #0: ffffffff8c1a68b0 (dup_mmap_sem){.+.+}-{0:0}, at: dup_mm kernel/fork.c:1466 [inline]
 #0: ffffffff8c1a68b0 (dup_mmap_sem){.+.+}-{0:0}, at: copy_mm+0x21f/0x1380 kernel/fork.c:1518
 #1: ffff88802c129d28 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock_killable include/linux/mmap_lock.h:87 [inline]
 #1: ffff88802c129d28 (&mm->mmap_lock){++++}-{3:3}, at: dup_mmap kernel/fork.c:504 [inline]
 #1: ffff88802c129d28 (&mm->mmap_lock){++++}-{3:3}, at: dup_mm kernel/fork.c:1466 [inline]
 #1: ffff88802c129d28 (&mm->mmap_lock){++++}-{3:3}, at: copy_mm+0x238/0x1380 kernel/fork.c:1518
6 locks held by syz-executor/4300:
 #0: ffff88807f2bc460 (sb_writers#8){.+.+}-{0:0}, at: vfs_write+0x28a/0xd00 fs/read_write.c:590
 #1: ffff88807ab80c88 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1e5/0x4c0 fs/kernfs/file.c:287
 #2: ffff888023151008 (kn->active#361){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x208/0x4c0 fs/kernfs/file.c:288
 #3: ffffffff8cb72648 (nsim_bus_dev_list_lock){+.+.}-{3:3}, at: new_device_store+0x13c/0x740 drivers/net/netdevsim/bus.c:295
 #4: ffff888059b81178 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:764 [inline]
 #4: ffff888059b81178 (&dev->mutex){....}-{3:3}, at: __device_attach+0x85/0x460 drivers/base/dd.c:954
 #5: ffffffff8d232788 (rtnl_mutex){+.+.}-{3:3}, at: nsim_init_netdevsim drivers/net/netdevsim/netdev.c:310 [inline]
 #5: ffffffff8d232788 (rtnl_mutex){+.+.}-{3:3}, at: nsim_create+0x2ef/0x3e0 drivers/net/netdevsim/netdev.c:365
4 locks held by syz-executor/4303:
 #0: ffffffff8d28f190 (cb_lock){++++}-{3:3}, at: genl_rcv+0x15/0x40 net/netlink/genetlink.c:802
 #1: ffffffff8d28efe8 (genl_mutex){+.+.}-{3:3}, at: genl_lock net/netlink/genetlink.c:33 [inline]
 #1: ffffffff8d28efe8 (genl_mutex){+.+.}-{3:3}, at: genl_rcv_msg+0x137/0xf40 net/netlink/genetlink.c:790
 #2: ffffffff8d232788 (rtnl_mutex){+.+.}-{3:3}, at: wg_set_device+0xf2/0x1e70 drivers/net/wireguard/netlink.c:504
 #3: ffff888076ec93e8 (&wg->device_update_lock){+.+.}-{3:3}, at: wg_set_device+0x10a/0x1e70 drivers/net/wireguard/netlink.c:505
3 locks held by kworker/1:12/4307:
 #0: ffff888016871938 ((wq_completion)events_power_efficient){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
 #1: ffffc9000314fd00 ((reg_check_chans).work){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
 #2: ffffffff8d232788 (rtnl_mutex){+.+.}-{3:3}, at: reg_check_chans_work+0x81/0xa50 net/wireless/reg.c:2437
7 locks held by syz-executor/4308:
 #0: ffff888076ab0460 (sb_writers#11){.+.+}-{0:0}, at: vfs_write+0x28a/0xd00 fs/read_write.c:590
 #1: ffff888025143488 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1e5/0x4c0 fs/kernfs/file.c:287
 #2: ffffffff8c141fc8 (cgroup_mutex){+.+.}-{3:3}, at: cgroup_kn_lock_live+0xee/0x230 kernel/cgroup/cgroup.c:1662
 #3: ffffffff8bfbae90 (cpu_hotplug_lock){++++}-{0:0}, at: cgroup_attach_lock kernel/cgroup/cgroup.c:2411 [inline]
 #3: ffffffff8bfbae90 (cpu_hotplug_lock){++++}-{0:0}, at: cgroup_procs_write_start+0x17c/0x580 kernel/cgroup/cgroup.c:2921
 #4: ffffffff8c1421b0 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: cgroup_attach_lock kernel/cgroup/cgroup.c:2413 [inline]
 #4: ffffffff8c1421b0 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: cgroup_procs_write_start+0x192/0x580 kernel/cgroup/cgroup.c:2921
 #5: ffffffff8c14fb08 (cpuset_mutex){+.+.}-{3:3}, at: cpuset_attach+0xac/0x5f0 kernel/cgroup/cpuset.c:2348
 #6: ffff88807cfd4e28 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock include/linux/mmap_lock.h:71 [inline]
 #6: ffff88807cfd4e28 (&mm->mmap_lock){++++}-{3:3}, at: mpol_rebind_mm+0x33/0x2c0 mm/mempolicy.c:381
1 lock held by syz-executor/4313:
 #0: ffffffff8d232788 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8d232788 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x7a5/0xe90 net/core/rtnetlink.c:5681

=============================================

NMI backtrace for cpu 0
CPU: 0 PID: 27 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x397/0x3d0 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:212 [inline]
 watchdog+0xe0f/0xe50 kernel/hung_task.c:369
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 3542 Comm: syslogd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:check_preemption_disabled+0x60/0x110 lib/smp_processor_id.c:19
Code: 00 48 3b 4c 24 08 0f 85 c4 00 00 00 48 83 c4 10 5b 41 5e 41 5f 5d c3 48 c7 04 24 00 00 00 00 9c 8f 04 24 f7 04 24 00 02 00 00 <74> cc 65 4c 8b 3d f6 77 60 76 41 f6 47 2f 04 74 0a 41 83 bf 10 04
RSP: 0018:ffffc90002e6f8e0 EFLAGS: 00000046
RAX: 0000000000000001 RBX: ffff88807e280000 RCX: 0000000080000000
RDX: 0000000000000000 RSI: ffffffff8a0b29e0 RDI: ffffffff8a59e800
RBP: 00000000ffffffff R08: dffffc0000000000 R09: ffffc90002e6fc18
R10: fffff520005cdf87 R11: 1ffff920005cdf83 R12: dffffc0000000000
R13: 0000000000000246 R14: ffffffff8c11c780 R15: 00000000ffffffff
FS:  00007f8e3080fc80(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff8a02ab000 CR3: 000000007e5df000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 lockdep_recursion_inc kernel/locking/lockdep.c:431 [inline]
 lock_is_held_type+0x75/0x190 kernel/locking/lockdep.c:5665
 lock_is_held include/linux/lockdep.h:287 [inline]
 ___might_sleep+0xa3/0x600 kernel/sched/core.c:9624
 begin_current_label_crit_section security/apparmor/include/cred.h:164 [inline]
 aa_sk_perm+0x172/0x8f0 security/apparmor/net.c:173
 security_socket_recvmsg+0x75/0xb0 security/security.c:2258
 sock_recvmsg net/socket.c:984 [inline]
 sock_read_iter+0x226/0x340 net/socket.c:1067
 call_read_iter include/linux/fs.h:2167 [inline]
 new_sync_read fs/read_write.c:404 [inline]
 vfs_read+0x725/0xcf0 fs/read_write.c:485
 ksys_read+0x14d/0x250 fs/read_write.c:623
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f8e3095f407
Code: 48 89 fa 4c 89 df e8 38 aa 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff
RSP: 002b:00007ffde8091600 EFLAGS: 00000202 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007f8e3080fc80 RCX: 00007f8e3095f407
RDX: 00000000000000ff RSI: 000056018a363950 RDI: 0000000000000000
RBP: 000056018a363910 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 000056018a3639a1
R13: 0000000000000000 R14: 000056018a363950 R15: 000056016fa8dd98
 </TASK>

Crashes (58):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/01/12 05:28 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in cgroup_can_fork
2025/12/06 12:00 linux-5.15.y cc5ec8769306 d6526ea3 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: task hung in cgroup_can_fork
2025/11/10 01:29 linux-5.15.y cc5ec8769306 4e1406b4 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in cgroup_can_fork
2025/10/27 02:00 linux-5.15.y ac56c046adf4 c0460fcd .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: task hung in cgroup_can_fork
2025/10/24 07:53 linux-5.15.y ac56c046adf4 c0460fcd .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: task hung in cgroup_can_fork
2025/10/09 21:06 linux-5.15.y 29e53a5b1c4f 7e2882b3 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in cgroup_can_fork
2025/10/09 07:48 linux-5.15.y 29e53a5b1c4f 7e2882b3 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in cgroup_can_fork
2025/10/09 02:39 linux-5.15.y 29e53a5b1c4f 7e2882b3 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in cgroup_can_fork
2025/10/05 02:03 linux-5.15.y 29e53a5b1c4f 49379ee0 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: task hung in cgroup_can_fork
2025/10/03 11:53 linux-5.15.y 29e53a5b1c4f 49379ee0 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: task hung in cgroup_can_fork
2025/09/24 03:51 linux-5.15.y 43bb85222e53 e667a34f .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: task hung in cgroup_can_fork
2026/01/10 14:08 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: task hung in cgroup_can_fork
2025/11/24 05:32 linux-5.15.y cc5ec8769306 4fb8ef37 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: task hung in cgroup_can_fork
2025/11/23 14:49 linux-5.15.y cc5ec8769306 4fb8ef37 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in cgroup_can_fork
2025/11/23 09:37 linux-5.15.y cc5ec8769306 4fb8ef37 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: task hung in cgroup_can_fork
2025/11/10 05:41 linux-5.15.y cc5ec8769306 4e1406b4 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: task hung in cgroup_can_fork
2025/10/10 10:00 linux-5.15.y 29e53a5b1c4f ff1712fe .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: task hung in cgroup_can_fork
2025/10/04 16:39 linux-5.15.y 29e53a5b1c4f 49379ee0 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: task hung in cgroup_can_fork
2025/09/23 15:26 linux-5.15.y 43bb85222e53 0ac7291c .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: task hung in cgroup_can_fork
2026/01/05 10:07 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in cgroup_can_fork
2025/12/14 19:26 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in cgroup_can_fork
2025/12/07 04:21 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in cgroup_can_fork
2025/11/21 07:06 linux-5.15.y cc5ec8769306 280ea308 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: task hung in cgroup_can_fork
2025/11/18 12:51 linux-5.15.y cc5ec8769306 ef766cd7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: task hung in cgroup_can_fork
2025/11/17 17:05 linux-5.15.y cc5ec8769306 ef766cd7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in cgroup_can_fork
2025/11/15 17:16 linux-5.15.y cc5ec8769306 f7988ea4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in cgroup_can_fork
2025/11/11 23:09 linux-5.15.y cc5ec8769306 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in cgroup_can_fork
2025/11/06 06:35 linux-5.15.y cc5ec8769306 a6c9c731 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: task hung in cgroup_can_fork
2025/11/03 20:40 linux-5.15.y cc5ec8769306 686bf657 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: task hung in cgroup_can_fork
2025/10/31 01:17 linux-5.15.y cc5ec8769306 2c50b6a9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: task hung in cgroup_can_fork
2025/10/30 22:17 linux-5.15.y cc5ec8769306 2c50b6a9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in cgroup_can_fork
2025/10/30 22:11 linux-5.15.y cc5ec8769306 2c50b6a9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in cgroup_can_fork
2025/10/21 03:08 linux-5.15.y ac56c046adf4 9832ed61 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: task hung in cgroup_can_fork
2025/10/21 03:03 linux-5.15.y ac56c046adf4 9832ed61 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: task hung in cgroup_can_fork
2025/10/20 15:01 linux-5.15.y ac56c046adf4 d422939c .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: task hung in cgroup_can_fork
2025/10/19 15:56 linux-5.15.y ac56c046adf4 1c8c8cd8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: task hung in cgroup_can_fork
2025/10/17 22:16 linux-5.15.y 29e53a5b1c4f 1c8c8cd8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: task hung in cgroup_can_fork
2025/10/15 21:27 linux-5.15.y 29e53a5b1c4f 19568248 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in cgroup_can_fork
2025/10/13 18:29 linux-5.15.y 29e53a5b1c4f b6605ba8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in cgroup_can_fork
2025/10/11 15:26 linux-5.15.y 29e53a5b1c4f ff1712fe .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: task hung in cgroup_can_fork
2025/10/11 10:43 linux-5.15.y 29e53a5b1c4f ff1712fe .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: task hung in cgroup_can_fork
2025/10/11 09:39 linux-5.15.y 29e53a5b1c4f ff1712fe .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: task hung in cgroup_can_fork
2025/10/09 00:31 linux-5.15.y 29e53a5b1c4f 7e2882b3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: task hung in cgroup_can_fork
2025/10/08 03:36 linux-5.15.y 29e53a5b1c4f 7e2882b3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: task hung in cgroup_can_fork
2025/10/08 02:33 linux-5.15.y 29e53a5b1c4f 7e2882b3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in cgroup_can_fork
2025/10/07 22:33 linux-5.15.y 29e53a5b1c4f 7e2882b3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: task hung in cgroup_can_fork
2025/10/07 04:28 linux-5.15.y 29e53a5b1c4f 8ef35d49 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in cgroup_can_fork
2025/10/07 00:05 linux-5.15.y 29e53a5b1c4f 8ef35d49 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: task hung in cgroup_can_fork
2025/10/02 18:54 linux-5.15.y 29e53a5b1c4f 49379ee0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in cgroup_can_fork
2025/10/01 15:44 linux-5.15.y 43bb85222e53 a1859138 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in cgroup_can_fork
2025/09/30 00:09 linux-5.15.y 43bb85222e53 86341da6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: task hung in cgroup_can_fork
2025/09/24 10:11 linux-5.15.y 43bb85222e53 0abd0691 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in cgroup_can_fork
2025/09/23 22:07 linux-5.15.y 43bb85222e53 e667a34f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in cgroup_can_fork
2025/09/23 04:50 linux-5.15.y 43bb85222e53 0ac7291c .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in cgroup_can_fork
2025/09/11 03:22 linux-5.15.y de9476bb4f1b fdeaa69b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: task hung in cgroup_can_fork
* Struck through repros no longer work on HEAD.