INFO: task hung in cangw_pernet_exit (2)

Status: upstream: reported on 2026/04/16 19:03
Reported-by: syzbot+f954b2c9821ea248f90f@syzkaller.appspotmail.com
First crash: 108d, last: 18d
▶ ▼ Similar bugs (6)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.19 INFO: task hung in cangw_pernet_exit 1 1 2206d 2206d 0/1 auto-closed as invalid on 2020/11/15 21:42
upstream INFO: task hung in cangw_pernet_exit net 1 14 2550d 3047d 0/29 closed as invalid on 2019/10/23 07:27
linux-4.19 INFO: task hung in cangw_pernet_exit (2) 1 6 1477d 1712d 0/1 auto-obsoleted due to no activity on 2022/11/15 03:06
upstream INFO: task hung in cangw_pernet_exit (2) can 1 85 1953d 2129d 0/29 auto-closed as invalid on 2021/06/26 13:07
upstream INFO: task hung in cangw_pernet_exit (3) can 1 syz unreliable 290 1679d 1785d 0/29 closed as invalid on 2022/02/08 10:22
linux-5.15 INFO: task hung in cangw_pernet_exit 1 27 760d 803d 0/3 auto-obsoleted due to no activity on 2024/09/11 11:31

Sample crash report:
INFO: task kworker/u4:0:9 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:0    state:D stack:21472 pid:    9 ppid:     2 flags:0x00004000
Workqueue: netns cleanup_net
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11c3/0x4350 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+0xdf5/0x2400 kernel/locking/mutex.c:669
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
 cangw_pernet_exit+0xe/0x20 net/can/gw.c:1279
 ops_exit_list net/core/net_namespace.c:172 [inline]
 cleanup_net+0x703/0xba0 net/core/net_namespace.c:635
 process_one_work+0x867/0xff0 kernel/workqueue.c:2310
 worker_thread+0xad7/0x12a0 kernel/workqueue.c:2457
 kthread+0x42e/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
INFO: task kworker/u4:3:1166 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:21904 pid: 1166 ppid:     2 flags:0x00004000
Workqueue: events_unbound linkwatch_event
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11c3/0x4350 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+0xdf5/0x2400 kernel/locking/mutex.c:669
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
 linkwatch_event+0xa/0x50 net/core/link_watch.c:251
 process_one_work+0x867/0xff0 kernel/workqueue.c:2310
 worker_thread+0xad7/0x12a0 kernel/workqueue.c:2457
 kthread+0x42e/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
INFO: task kworker/1:19:20072 blocked for more than 144 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/1:19    state:D stack:23520 pid:20072 ppid:     2 flags:0x00004000
Workqueue: events nsim_dev_trap_report_work
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11c3/0x4350 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+0xdf5/0x2400 kernel/locking/mutex.c:669
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
 nsim_dev_trap_report_work+0x56/0xab0 drivers/net/netdevsim/dev.c:757
 process_one_work+0x867/0xff0 kernel/workqueue.c:2310
 worker_thread+0xad7/0x12a0 kernel/workqueue.c:2457
 kthread+0x42e/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
INFO: task syz-executor:21949 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:18304 pid:21949 ppid: 21911 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11c3/0x4350 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+0xdf5/0x2400 kernel/locking/mutex.c:669
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
 netdev_run_todo+0x8dd/0xac0 net/core/dev.c:10722
 nsim_destroy+0xb2/0x150 drivers/net/netdevsim/netdev.c:387
 __nsim_dev_port_del+0x155/0x1c0 drivers/net/netdevsim/dev.c:1349
 nsim_dev_port_del_all drivers/net/netdevsim/dev.c:1362 [inline]
 nsim_dev_reload_destroy+0x160/0x230 drivers/net/netdevsim/dev.c:1561
 nsim_dev_remove+0x59/0x120 drivers/net/netdevsim/dev.c:1577
 __device_release_driver drivers/base/dd.c:1247 [inline]
 device_release_driver_internal+0x44c/0x710 drivers/base/dd.c:1282
 bus_remove_device+0x2dd/0x400 drivers/base/bus.c:531
 device_del+0x63f/0xa80 drivers/base/core.c:3615
 device_unregister+0x1c/0xc0 drivers/base/core.c:3660
 nsim_bus_dev_del drivers/net/netdevsim/bus.c:454 [inline]
 del_device_store+0x295/0x3a0 drivers/net/netdevsim/bus.c:354
 kernfs_fop_write_iter+0x3a8/0x500 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+0x748/0xd70 fs/read_write.c:594
 ksys_write+0x153/0x260 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: 0033:0x7f889ca2268e
RSP: 002b:00007ffcc456d598 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000555593703500 RCX: 00007f889ca2268e
RDX: 0000000000000001 RSI: 00007ffcc456d620 RDI: 0000000000000005
RBP: 00007f889caf86f2 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007ffcc456d620 R14: 00007f889d818620 R15: 0000000000000003
 </TASK>

Showing all locks held in the system:
4 locks held by kworker/u4:0/9:
 #0: ffff888016dcd938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1
 #1: ffffc90000ce7d00 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285
 #2: ffffffff8d43f210 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x148/0xba0 net/core/net_namespace.c:589
 #3: ffffffff8d44b148 (rtnl_mutex){+.+.}-{3:3}, at: cangw_pernet_exit+0xe/0x20 net/can/gw.c:1279
1 lock held by khungtaskd/27:
 #0: ffffffff8c31ef20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
3 locks held by kworker/u4:3/1166:
 #0: ffff888016c79138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1
 #1: ffffc90004dd7d00 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285
 #2: ffffffff8d44b148 (rtnl_mutex){+.+.}-{3:3}, at: linkwatch_event+0xa/0x50 net/core/link_watch.c:251
1 lock held by jbd2/sda1-8/3521:
 #0: ffffffff8c3afe68 (oom_lock){+.+.}-{3:3}, at: __alloc_pages_may_oom mm/page_alloc.c:4308 [inline]
 #0: ffffffff8c3afe68 (oom_lock){+.+.}-{3:3}, at: __alloc_pages_slowpath+0x1bad/0x2700 mm/page_alloc.c:5177
2 locks held by klogd/3548:
 #0: ffff8880268fad70 (mapping.invalidate_lock){++++}-{3:3}, at: filemap_invalidate_lock_shared include/linux/fs.h:842 [inline]
 #0: ffff8880268fad70 (mapping.invalidate_lock){++++}-{3:3}, at: filemap_fault+0x83f/0x13a0 mm/filemap.c:3096
 #1: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __perform_reclaim mm/page_alloc.c:4654 [inline]
 #1: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_direct_reclaim mm/page_alloc.c:4678 [inline]
 #1: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_slowpath+0x1017/0x2700 mm/page_alloc.c:5128
2 locks held by udevd/3559:
 #0: ffff8880268fad70 (mapping.invalidate_lock){++++}-{3:3}, at: filemap_invalidate_lock_shared include/linux/fs.h:842 [inline]
 #0: ffff8880268fad70 (mapping.invalidate_lock){++++}-{3:3}, at: filemap_fault+0x83f/0x13a0 mm/filemap.c:3096
 #1: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __perform_reclaim mm/page_alloc.c:4654 [inline]
 #1: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_direct_reclaim mm/page_alloc.c:4678 [inline]
 #1: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_slowpath+0x1017/0x2700 mm/page_alloc.c:5128
2 locks held by crond/3926:
 #0: ffff8880268fad70 (mapping.invalidate_lock){++++}-{3:3}, at: filemap_invalidate_lock_shared include/linux/fs.h:842 [inline]
 #0: ffff8880268fad70 (mapping.invalidate_lock){++++}-{3:3}, at: filemap_fault+0x83f/0x13a0 mm/filemap.c:3096
 #1: 
ffffffff8c3debc0
 (fs_reclaim){+.+.}-{0:0}, at: __perform_reclaim mm/page_alloc.c:4654 [inline]
 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_direct_reclaim mm/page_alloc.c:4678 [inline]
 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_slowpath+0x1017/0x2700 mm/page_alloc.c:5128
2 locks held by getty/3938:
 #0: ffff88802c2bc098
 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
 #1: ffffc900021ce2e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x594/0x1a50 drivers/tty/n_tty.c:2158
2 locks held by sshd-session/4173:
 #0: 
ffff8880268fad70 (mapping.invalidate_lock
){++++}-{3:3}
, at: filemap_invalidate_lock_shared include/linux/fs.h:842 [inline]
, at: filemap_fault+0x83f/0x13a0 mm/filemap.c:3096
 #1: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __perform_reclaim mm/page_alloc.c:4654 [inline]
 #1: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_direct_reclaim mm/page_alloc.c:4678 [inline]
 #1: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_slowpath+0x1017/0x2700 mm/page_alloc.c:5128
1 lock held by syz-executor/4174:
 #0: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __perform_reclaim mm/page_alloc.c:4654 [inline]
 #0: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_direct_reclaim mm/page_alloc.c:4678 [inline]
 #0: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_slowpath+0x1017/0x2700 mm/page_alloc.c:5128
2 locks held by syz-executor/12804:
 #0: ffff888073db0590 (mapping.invalidate_lock){++++}-{3:3}, at: filemap_invalidate_lock_shared include/linux/fs.h:842 [inline]
 #0: ffff888073db0590 (mapping.invalidate_lock){++++}-{3:3}, at: filemap_fault+0x83f/0x13a0 mm/filemap.c:3096
 #1: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __perform_reclaim mm/page_alloc.c:4654 [inline]
 #1: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_direct_reclaim mm/page_alloc.c:4678 [inline]
 #1: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_slowpath+0x1017/0x2700 mm/page_alloc.c:5128
2 locks held by syz-executor/14157:
 #0: ffff888073db0590 (mapping.invalidate_lock){++++}-{3:3}, at: filemap_invalidate_lock_shared include/linux/fs.h:842 [inline]
 #0: ffff888073db0590 (mapping.invalidate_lock){++++}-{3:3}, at: filemap_fault+0x83f/0x13a0 mm/filemap.c:3096
 #1: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __perform_reclaim mm/page_alloc.c:4654 [inline]
 #1: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_direct_reclaim mm/page_alloc.c:4678 [inline]
 #1: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_slowpath+0x1017/0x2700 mm/page_alloc.c:5128
3 locks held by kworker/1:15/17572:
 #0: ffff888016c70938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1
 #1: ffffc900032efd00 ((work_completion)(&(&vi->refill)->work)){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285
 #2: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __perform_reclaim mm/page_alloc.c:4654 [inline]
 #2: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_direct_reclaim mm/page_alloc.c:4678 [inline]
 #2: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_slowpath+0x1017/0x2700 mm/page_alloc.c:5128
3 locks held by kworker/1:16/17574:
 #0: ffff888016c70938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1
 #1: ffffc9000340fd00 ((work_completion)(&(&krcp->page_cache_work)->work)){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285
 #2: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __perform_reclaim mm/page_alloc.c:4654 [inline]
 #2: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_direct_reclaim mm/page_alloc.c:4678 [inline]
 #2: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_slowpath+0x1017/0x2700 mm/page_alloc.c:5128
3 locks held by kworker/1:17/17575:
 #0: ffff88802b593538 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1
 #1: ffffc9000343fd00 ((addr_chk_work).work){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285
 #2: ffffffff8d44b148 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_verify_work+0xa/0x20 net/ipv6/addrconf.c:4657
2 locks held by udevd/19366:
 #0: ffff88801d359980 (mapping.invalidate_lock){++++}-{3:3}, at: filemap_invalidate_lock_shared include/linux/fs.h:842 [inline]
 #0: ffff88801d359980 (mapping.invalidate_lock){++++}-{3:3}, at: filemap_fault+0x83f/0x13a0 mm/filemap.c:3096
 #1: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __perform_reclaim mm/page_alloc.c:4654 [inline]
 #1: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_direct_reclaim mm/page_alloc.c:4678 [inline]
 #1: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_slowpath+0x1017/0x2700 mm/page_alloc.c:5128
3 locks held by kworker/1:19/20072:
 #0: ffff888016c70938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1
 #1: ffffc90003a47d00 ((work_completion)(&(&nsim_dev->trap_data->trap_report_dw)->work)){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285
 #2: ffff888061245400 (&nsim_dev->port_list_lock#2){+.+.}-{3:3}, at: nsim_dev_trap_report_work+0x56/0xab0 drivers/net/netdevsim/dev.c:757
2 locks held by syz.3.3645/21612:
 #0: ffff88807410a120 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1744 [inline]
 #0: ffff88807410a120 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_setsockopt+0x7f3/0x1af0 net/packet/af_packet.c:3835
 #1: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __perform_reclaim mm/page_alloc.c:4654 [inline]
 #1: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_direct_reclaim mm/page_alloc.c:4678 [inline]
 #1: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_slowpath+0x1017/0x2700 mm/page_alloc.c:5128
7 locks held by syz-executor/21949:
 #0: ffff88807e850460 (sb_writers#8){.+.+}-{0:0}, at: vfs_write+0x296/0xd70 fs/read_write.c:590
 #1: ffff88807f6f7488 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1dc/0x500 fs/kernfs/file.c:287
 #2: ffff8881482c6660 (kn->active#284){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x1fd/0x500 fs/kernfs/file.c:288
 #3: ffffffff8cd88da8 (nsim_bus_dev_list_lock){+.+.}-{3:3}, at: del_device_store+0xd3/0x3a0 drivers/net/netdevsim/bus.c:344
 #4: ffff888061240178 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:809 [inline]
 #4: ffff888061240178 (&dev->mutex){....}-{3:3}, at: __device_driver_lock drivers/base/dd.c:1064 [inline]
 #4: ffff888061240178 (&dev->mutex){....}-{3:3}, at: device_release_driver_internal+0xa1/0x710 drivers/base/dd.c:1279
 #5: ffff888061245400 (&nsim_dev->port_list_lock#2){+.+.}-{3:3}, at: nsim_dev_port_del_all drivers/net/netdevsim/dev.c:1359 [inline]
 #5: ffff888061245400 (&nsim_dev->port_list_lock#2){+.+.}-{3:3}, at: nsim_dev_reload_destroy+0x109/0x230 drivers/net/netdevsim/dev.c:1561
 #6: ffffffff8d44b148 (rtnl_mutex){+.+.}-{3:3}, at: netdev_run_todo+0x8dd/0xac0 net/core/dev.c:10722
2 locks held by syz-executor/21956:
 #0: ffffffff8d44b148 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8d44b148 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x7d6/0xf00 net/core/rtnetlink.c:5685
 #1: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __perform_reclaim mm/page_alloc.c:4654 [inline]
 #1: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_direct_reclaim mm/page_alloc.c:4678 [inline]
 #1: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_slowpath+0x1017/0x2700 mm/page_alloc.c:5128
2 locks held by syz.7.3784/22052:
 #0: ffff888073db0f88 (mapping.invalidate_lock){++++}-{3:3}, at: filemap_invalidate_lock_shared include/linux/fs.h:842 [inline]
 #0: ffff888073db0f88 (mapping.invalidate_lock){++++}-{3:3}, at: filemap_fault+0x83f/0x13a0 mm/filemap.c:3096
 #1: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __perform_reclaim mm/page_alloc.c:4654 [inline]
 #1: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_direct_reclaim mm/page_alloc.c:4678 [inline]
 #1: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_slowpath+0x1017/0x2700 mm/page_alloc.c:5128
2 locks held by syz.1.3783/22054:
2 locks held by dhcpcd-run-hook/22056:
 #0: ffff8880268fad70 (mapping.invalidate_lock){++++}-{3:3}, at: filemap_invalidate_lock_shared include/linux/fs.h:842 [inline]
 #0: ffff8880268fad70 (mapping.invalidate_lock){++++}-{3:3}, at: filemap_fault+0x83f/0x13a0 mm/filemap.c:3096
 #1: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __perform_reclaim mm/page_alloc.c:4654 [inline]
 #1: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_direct_reclaim mm/page_alloc.c:4678 [inline]
 #1: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_slowpath+0x1017/0x2700 mm/page_alloc.c:5128

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

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 05/09/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x3a2/0x3d0 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+0xe1b/0xe60 kernel/hung_task.c:369
 kthread+0x42e/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: 144 Comm: kworker/u4:1 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Workqueue: bat_events batadv_nc_worker
RIP: 0010:task_wait_context kernel/locking/lockdep.c:-1 [inline]
RIP: 0010:check_wait_context kernel/locking/lockdep.c:4707 [inline]
RIP: 0010:__lock_acquire+0x880/0x7b50 kernel/locking/lockdep.c:4962
Code: 18 75 2b 48 8b 84 24 b8 00 00 00 42 0f b6 04 00 84 c0 0f 85 2c 63 00 00 48 8b 84 24 88 00 00 00 83 38 00 41 0f 94 c5 45 00 ed <41> 80 c5 02 48 8b 44 24 60 42 0f b6 04 00 84 c0 0f 85 84 60 00 00
RSP: 0000:ffffc9000174f840 EFLAGS: 00000002
RAX: ffff888019b9a894 RBX: ffff888019b9a8a8 RCX: 0000000000000001
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff901e90c0
RBP: ffffc9000174fa70 R08: dffffc0000000000 R09: 1ffffffff203d218
R10: dffffc0000000000 R11: fffffbfff203d219 R12: 0000000000000000
R13: ffff888019b99d02 R14: 0000000000000000 R15: ffffffffffffffff
FS:  0000000000000000(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f28a59a5e4a CR3: 0000000070a84000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 lock_acquire+0x19e/0x400 kernel/locking/lockdep.c:5623
 rcu_lock_acquire+0x2a/0x30 include/linux/rcupdate.h:313
 rcu_read_lock include/linux/rcupdate.h:740 [inline]
 batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:412 [inline]
 batadv_nc_worker+0xc9/0x5c0 net/batman-adv/network-coding.c:723
 process_one_work+0x867/0xff0 kernel/workqueue.c:2310
 worker_thread+0xad7/0x12a0 kernel/workqueue.c:2457
 kthread+0x42e/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>

Crashes (4):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/07/15 20:58 linux-5.15.y c86c4726e7f0 a4ed0f4f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in cangw_pernet_exit
2026/07/07 10:24 linux-5.15.y c86c4726e7f0 8e71ce95 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in cangw_pernet_exit
2026/04/27 00:44 linux-5.15.y b9d57c40a767 9c2d0995 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in cangw_pernet_exit
2026/04/16 19:02 linux-5.15.y 91d48252ad4b 4743f87d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in cangw_pernet_exit
* Struck through repros no longer work on HEAD.