Subject: [syzbot] [net?] INFO: task hung in cleanup_net (7)

From: syzbot <[email-masked]>
Date: Thu, 11 Jul 2024 15:48:21 -0700

Hello,

syzbot found the following issue on:

HEAD commit:    c6653f49e4fd Merge tag 'powerpc-6.10-4' of git://git.kerne..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=16e85369980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=864caee5f78cab51
dashboard link: https://syzkaller.appspot.com/bug?extid=09e91cb5dd034b2d3ad4
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/883870bfa71b/disk-c6653f49.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/f2d0f532ed6a/vmlinux-c6653f49.xz
kernel image: https://storage.googleapis.com/syzbot-assets/14f12438424f/bzImage-c6653f49.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: [email-masked]

INFO: task kworker/u8:6:1040 blocked for more than 143 seconds.
      Not tainted 6.10.0-rc6-syzkaller-00223-gc6653f49e4fd #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:6    state:D stack:22248 pid:1040  tgid:1040  ppid:2      flags:0x00004000
Workqueue: netns cleanup_net
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5408 [inline]
 __schedule+0x17e8/0x4a20 kernel/sched/core.c:6745
 __schedule_loop kernel/sched/core.c:6822 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6837
 schedule_timeout+0xb0/0x310 kernel/time/timer.c:2557
 do_wait_for_common kernel/sched/completion.c:95 [inline]
 __wait_for_common kernel/sched/completion.c:116 [inline]
 wait_for_common kernel/sched/completion.c:127 [inline]
 wait_for_completion+0x355/0x620 kernel/sched/completion.c:148
 __flush_work+0xaa9/0xd00 kernel/workqueue.c:4227
 flush_all_backlogs net/core/dev.c:6000 [inline]
 unregister_netdevice_many_notify+0x8a0/0x16b0 net/core/dev.c:11201
 cleanup_net+0x75d/0xcc0 net/core/net_namespace.c:635
 process_one_work kernel/workqueue.c:3248 [inline]
 process_scheduled_works+0xa2c/0x1830 kernel/workqueue.c:3329
 worker_thread+0x86d/0xd50 kernel/workqueue.c:3409
 kthread+0x2f0/0x390 kernel/kthread.c:389
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
INFO: task kworker/u8:9:2843 blocked for more than 144 seconds.
      Not tainted 6.10.0-rc6-syzkaller-00223-gc6653f49e4fd #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:9    state:D
 stack:23640 pid:2843  tgid:2843  ppid:2      flags:0x00004000
Workqueue: ipv6_addrconf addrconf_dad_work

Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5408 [inline]
 __schedule+0x17e8/0x4a20 kernel/sched/core.c:6745
 __schedule_loop kernel/sched/core.c:6822 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6837
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6894
 __mutex_lock_common kernel/locking/mutex.c:684 [inline]
 __mutex_lock+0x6a4/0xd70 kernel/locking/mutex.c:752
 addrconf_dad_work+0xd0/0x16f0 net/ipv6/addrconf.c:4193
 process_one_work kernel/workqueue.c:3248 [inline]
 process_scheduled_works+0xa2c/0x1830 kernel/workqueue.c:3329
 worker_thread+0x86d/0xd50 kernel/workqueue.c:3409
 kthread+0x2f0/0x390 kernel/kthread.c:389
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
INFO: task kworker/1:2:2932 blocked for more than 145 seconds.
      Not tainted 6.10.0-rc6-syzkaller-00223-gc6653f49e4fd #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/1:2     state:D stack:25272 pid:2932  tgid:2932  ppid:2      flags:0x00004000
Workqueue: events request_firmware_work_func
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5408 [inline]
 __schedule+0x17e8/0x4a20 kernel/sched/core.c:6745
 __schedule_loop kernel/sched/core.c:6822 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6837
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6894
 __mutex_lock_common kernel/locking/mutex.c:684 [inline]
 __mutex_lock+0x6a4/0xd70 kernel/locking/mutex.c:752
 regdb_fw_cb+0x82/0x1c0 net/wireless/reg.c:1017
 request_firmware_work_func+0x1a4/0x280 drivers/base/firmware_loader/main.c:1167
 process_one_work kernel/workqueue.c:3248 [inline]
 process_scheduled_works+0xa2c/0x1830 kernel/workqueue.c:3329
 worker_thread+0x86d/0xd50 kernel/workqueue.c:3409
 kthread+0x2f0/0x390 kernel/kthread.c:389
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
INFO: task dhcpcd:4760 blocked for more than 146 seconds.
      Not tainted 6.10.0-rc6-syzkaller-00223-gc6653f49e4fd #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:dhcpcd          state:D stack:20384 pid:4760  tgid:4760  ppid:4759   flags:0x00000002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5408 [inline]
 __schedule+0x17e8/0x4a20 kernel/sched/core.c:6745
 __schedule_loop kernel/sched/core.c:6822 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6837
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6894
 __mutex_lock_common kernel/locking/mutex.c:684 [inline]
 __mutex_lock+0x6a4/0xd70 kernel/locking/mutex.c:752
 rtnl_lock net/core/rtnetlink.c:79 [inline]
 rtnetlink_rcv_msg+0x842/0x1180 net/core/rtnetlink.c:6632
 netlink_rcv_skb+0x1e3/0x430 net/netlink/af_netlink.c:2564
 netlink_unicast_kernel net/netlink/af_netlink.c:1335 [inline]
 netlink_unicast+0x7ea/0x980 net/netlink/af_netlink.c:1361
 netlink_sendmsg+0x8db/0xcb0 net/netlink/af_netlink.c:1905
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg+0x221/0x270 net/socket.c:745
 ____sys_sendmsg+0x525/0x7d0 net/socket.c:2585
 ___sys_sendmsg net/socket.c:2639 [inline]
 __sys_sendmsg+0x2b0/0x3a0 net/socket.c:2668
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fbaa016fa4b
RSP: 002b:00007ffecf670818 EFLAGS: 00000246
 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fbaa00976c0 RCX: 00007fbaa016fa4b
RDX: 0000000000000000 RSI: 00007ffecf6849c8 RDI: 0000000000000010
RBP: 0000000000000010 R08: 0000000000000000 R09: 00007ffecf6849c8
R10: 0000000000000000 R11: 0000000000000246 R12: ffffffffffffffff
R13: 00007ffecf6849c8 R14: 0000000000000030 R15: 0000000000000001
 </TASK>
INFO: task kworker/1:4:5146 blocked for more than 147 seconds.
      Not tainted 6.10.0-rc6-syzkaller-00223-gc6653f49e4fd #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/1:4     state:D
 stack:24872 pid:5146  tgid:5146  ppid:2      flags:0x00004000
Workqueue: events linkwatch_event

Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5408 [inline]
 __schedule+0x17e8/0x4a20 kernel/sched/core.c:6745
 __schedule_loop kernel/sched/core.c:6822 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6837
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6894
 __mutex_lock_common kernel/locking/mutex.c:684 [inline]
 __mutex_lock+0x6a4/0xd70 kernel/locking/mutex.c:752
 linkwatch_event+0xe/0x60 net/core/link_watch.c:276
 process_one_work kernel/workqueue.c:3248 [inline]
 process_scheduled_works+0xa2c/0x1830 kernel/workqueue.c:3329
 worker_thread+0x86d/0xd50 kernel/workqueue.c:3409
 kthread+0x2f0/0x390 kernel/kthread.c:389
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
INFO: task udevd:5147 blocked for more than 148 seconds.
      Not tainted 6.10.0-rc6-syzkaller-00223-gc6653f49e4fd #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:udevd           state:D
 stack:24864 pid:5147  tgid:5147  ppid:4546   flags:0x00000002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5408 [inline]
 __schedule+0x17e8/0x4a20 kernel/sched/core.c:6745
 __schedule_loop kernel/sched/core.c:6822 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6837
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6894
 __mutex_lock_common kernel/locking/mutex.c:684 [inline]
 __mutex_lock+0x6a4/0xd70 kernel/locking/mutex.c:752
 device_lock include/linux/device.h:1009 [inline]
 uevent_show+0x17d/0x340 drivers/base/core.c:2743
 dev_attr_show+0x55/0xc0 drivers/base/core.c:2437
 sysfs_kf_seq_show+0x331/0x4c0 fs/sysfs/file.c:59
 seq_read_iter+0x445/0xd60 fs/seq_file.c:230
 new_sync_read fs/read_write.c:395 [inline]
 vfs_read+0x9bd/0xbc0 fs/read_write.c:476
 ksys_read+0x1a0/0x2c0 fs/read_write.c:619
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f8f25168b6a
RSP: 002b:00007ffcd09cdd58 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 0000557c6193d2c0 RCX: 00007f8f25168b6a
RDX: 0000000000001000 RSI: 0000557c6192d930 RDI: 0000000000000008
RBP: 0000557c6193d2c0 R08: 0000000000000008 R09: 0000000000000008
R10: 000000000000010f R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000003fff R14: 00007ffcd09ce238 R15: 000000000000000a
 </TASK>
INFO: task kworker/1:6:5153 blocked for more than 148 seconds.
      Not tainted 6.10.0-rc6-syzkaller-00223-gc6653f49e4fd #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/1:6     state:D stack:20976 pid:5153  tgid:5153  ppid:2      flags:0x00004000
Workqueue: events switchdev_deferred_process_work
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5408 [inline]
 __schedule+0x17e8/0x4a20 kernel/sched/core.c:6745
 __schedule_loop kernel/sched/core.c:6822 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6837
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6894
 __mutex_lock_common kernel/locking/mutex.c:684 [inline]
 __mutex_lock+0x6a4/0xd70 kernel/locking/mutex.c:752
 switchdev_deferred_process_work+0xe/0x20 net/switchdev/switchdev.c:104
 process_one_work kernel/workqueue.c:3248 [inline]
 process_scheduled_works+0xa2c/0x1830 kernel/workqueue.c:3329
 worker_thread+0x86d/0xd50 kernel/workqueue.c:3409
 kthread+0x2f0/0x390 kernel/kthread.c:389
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
INFO: task syz.3.10:5176 blocked for more than 149 seconds.
      Not tainted 6.10.0-rc6-syzkaller-00223-gc6653f49e4fd #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.10        state:D
 stack:23776 pid:5176  tgid:5175  ppid:5109   flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5408 [inline]
 __schedule+0x17e8/0x4a20 kernel/sched/core.c:6745
 __schedule_loop kernel/sched/core.c:6822 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6837
 schedule_timeout+0xb0/0x310 kernel/time/timer.c:2557
 do_wait_for_common kernel/sched/completion.c:95 [inline]
 __wait_for_common kernel/sched/completion.c:116 [inline]
 wait_for_common kernel/sched/completion.c:127 [inline]
 wait_for_completion+0x355/0x620 kernel/sched/completion.c:148
 __flush_work+0xaa9/0xd00 kernel/workqueue.c:4227
 __lru_add_drain_all+0x4f6/0x560 mm/swap.c:902
 madvise_collapse+0x24b/0xcf0 mm/khugepaged.c:2712
 madvise_vma_behavior mm/madvise.c:1094 [inline]
 madvise_walk_vmas mm/madvise.c:1268 [inline]
 do_madvise+0xc5f/0x4590 mm/madvise.c:1464
 __do_sys_madvise mm/madvise.c:1481 [inline]
 __se_sys_madvise mm/madvise.c:1479 [inline]
 __x64_sys_madvise+0xa6/0xc0 mm/madvise.c:1479
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd40bb75bd9
RSP: 002b:00007fd40c8d1048 EFLAGS: 00000246
 ORIG_RAX: 000000000000001c
RAX: ffffffffffffffda RBX: 00007fd40bd03f60 RCX: 00007fd40bb75bd9
RDX: 0000000000000019 RSI: 0000000000600003 RDI: 0000000020000000
RBP: 00007fd40bbe4aa1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007fd40bd03f60 R15: 00007fd40be2fa68
 </TASK>
INFO: task syz-executor:5178 blocked for more than 150 seconds.
      Not tainted 6.10.0-rc6-syzkaller-00223-gc6653f49e4fd #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:25840 pid:5178  tgid:5178  ppid:1      flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5408 [inline]
 __schedule+0x17e8/0x4a20 kernel/sched/core.c:6745
 __schedule_loop kernel/sched/core.c:6822 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6837
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6894
 __mutex_lock_common kernel/locking/mutex.c:684 [inline]
 __mutex_lock+0x6a4/0xd70 kernel/locking/mutex.c:752
 ip_tunnel_init_net+0x20e/0x710 net/ipv4/ip_tunnel.c:1159
 ops_init+0x359/0x610 net/core/net_namespace.c:139
 setup_net+0x515/0xca0 net/core/net_namespace.c:343
 copy_net_ns+0x4e2/0x7b0 net/core/net_namespace.c:508
 create_new_namespaces+0x425/0x7b0 kernel/nsproxy.c:110
 unshare_nsproxy_namespaces+0x124/0x180 kernel/nsproxy.c:228
 ksys_unshare+0x619/0xc10 kernel/fork.c:3323
 __do_sys_unshare kernel/fork.c:3394 [inline]
 __se_sys_unshare kernel/fork.c:3392 [inline]
 __x64_sys_unshare+0x38/0x40 kernel/fork.c:3392
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb0b9177337
RSP: 002b:00007fb0b942ffa8 EFLAGS: 00000206 ORIG_RAX: 0000000000000110
RAX: ffffffffffffffda RBX: 00007fb0b91e4be6 RCX: 00007fb0b9177337
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000040000000
RBP: 0000000000000000 R08: 00007fb0b9e37d60 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 000000000000000c
R13: 0000000000000003 R14: 0000000000000009 R15: 0000000000000009
 </TASK>
INFO: task syz.0.11:5180 blocked for more than 151 seconds.
      Not tainted 6.10.0-rc6-syzkaller-00223-gc6653f49e4fd #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.11        state:D stack:24912 pid:5180  tgid:5180  ppid:5111   flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5408 [inline]
 __schedule+0x17e8/0x4a20 kernel/sched/core.c:6745
 __schedule_loop kernel/sched/core.c:6822 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6837
 schedule_timeout+0xb0/0x310 kernel/time/timer.c:2557
 do_wait_for_common kernel/sched/completion.c:95 [inline]
 __wait_for_common kernel/sched/completion.c:116 [inline]
 wait_for_common kernel/sched/completion.c:127 [inline]
 wait_for_completion+0x355/0x620 kernel/sched/completion.c:148
 __synchronize_srcu+0x357/0x400 kernel/rcu/srcutree.c:1396
 nbd_clear_que drivers/block/nbd.c:960 [inline]
 nbd_clear_sock drivers/block/nbd.c:1335 [inline]
 nbd_config_put+0x3d2/0x7e0 drivers/block/nbd.c:1358
 nbd_release+0x10b/0x130 drivers/block/nbd.c:1653
 bdev_release+0x5e3/0x700
 blkdev_release+0x15/0x20 block/fops.c:623
 __fput+0x24a/0x8a0 fs/file_table.c:422
 task_work_run+0x24f/0x310 kernel/task_work.c:180
 exit_task_work include/linux/task_work.h:38 [inline]
 do_exit+0xa27/0x27e0 kernel/exit.c:876
 do_group_exit+0x207/0x2c0 kernel/exit.c:1025
 get_signal+0x16a1/0x1740 kernel/signal.c:2909
 arch_do_signal_or_restart+0x96/0x860 arch/x86/kernel/signal.c:310
 exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0xc9/0x360 kernel/entry/common.c:218
 do_syscall_64+0x100/0x230 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f492bfa7bc5
RSP: 002b:00007f492c22fae0 EFLAGS: 00000293 ORIG_RAX: 00000000000000e6
RAX: 0000000000000000 RBX: 00007f492c103f60 RCX: 00007f492bfa7bc5
RDX: 00007f492c22fb20 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f492c105a60 R08: 0000000000000000 R09: 7fffffffffffffff
R10: 0000000000000000 R11: 0000000000000293 R12: 000000000001769b
R13: 000000000000015e R14: 00007f492c105a60 R15: 00007f492c22fc30
 </TASK>
Future hung task reports are suppressed, see sysctl kernel.hung_task_warnings

Showing all locks held in the system:
2 locks held by kworker/0:1/9:
5 locks held by kworker/u8:0/11:
 #0: ffff8880b953e798 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:559
 #1: 
ffff8880b9528948
 (

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