bisecting fixing commit since 64c0133eb88a3b0c11c42580a520fe78b71b3932 building syzkaller on f42dee6d5e501a061cdbb807672361369bf28492 testing commit 64c0133eb88a3b0c11c42580a520fe78b71b3932 with gcc (GCC) 8.1.0 run #0: crashed: INFO: task hung in switchdev_deferred_process_work run #1: crashed: INFO: task hung in addrconf_dad_work run #2: crashed: INFO: task hung in addrconf_dad_work run #3: crashed: INFO: task hung in linkwatch_event run #4: crashed: INFO: task hung in switchdev_deferred_process_work run #5: crashed: INFO: task hung in addrconf_dad_work run #6: crashed: INFO: task hung in addrconf_dad_work run #7: crashed: INFO: task hung in addrconf_dad_work run #8: crashed: INFO: task hung in addrconf_dad_work run #9: crashed: INFO: task hung in addrconf_dad_work testing current HEAD d45331b00ddb179e291766617259261c112db872 testing commit d45331b00ddb179e291766617259261c112db872 with gcc (GCC) 8.1.0 run #0: crashed: INFO: task hung in linkwatch_event run #1: crashed: INFO: task hung in addrconf_dad_work run #2: crashed: INFO: task hung in addrconf_dad_work run #3: crashed: INFO: task hung in switchdev_deferred_process_work run #4: crashed: INFO: task hung in addrconf_dad_work run #5: crashed: INFO: task hung in addrconf_dad_work run #6: crashed: INFO: task hung in addrconf_dad_work run #7: crashed: INFO: task hung in addrconf_dad_work run #8: crashed: INFO: task hung in switchdev_deferred_process_work run #9: crashed: INFO: task hung in addrconf_dad_work revisions tested: 2, total time: 25m42.345449918s (build: 12m1.871881898s, test: 12m15.483352897s) the crash still happens on HEAD crash: INFO: task hung in addrconf_dad_work 8021q: adding VLAN 0 to HW filter on device batadv0 8021q: adding VLAN 0 to HW filter on device batadv0 8021q: adding VLAN 0 to HW filter on device batadv0 8021q: adding VLAN 0 to HW filter on device batadv0 INFO: task kworker/0:2:2964 blocked for more than 143 seconds. Not tainted 5.3.0-rc4 #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/0:2 D26144 2964 2 0x80004000 Workqueue: ipv6_addrconf addrconf_dad_work Call Trace: context_switch kernel/sched/core.c:3254 [inline] __schedule+0x719/0x1530 kernel/sched/core.c:3880 schedule+0x8f/0x260 kernel/sched/core.c:3944 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:4003 __mutex_lock_common kernel/locking/mutex.c:1007 [inline] __mutex_lock+0x8bf/0x1410 kernel/locking/mutex.c:1077 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1092 rtnl_lock+0x12/0x20 net/core/rtnetlink.c:72 addrconf_dad_work+0xa2/0xfc0 net/ipv6/addrconf.c:4032 process_one_work+0x85b/0x1640 kernel/workqueue.c:2269 worker_thread+0x85/0xb60 kernel/workqueue.c:2415 kthread+0x334/0x3f0 kernel/kthread.c:255 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352 INFO: task kworker/1:3:7268 blocked for more than 143 seconds. Not tainted 5.3.0-rc4 #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/1:3 D26576 7268 2 0x80004000 Workqueue: ipv6_addrconf addrconf_dad_work Call Trace: context_switch kernel/sched/core.c:3254 [inline] __schedule+0x719/0x1530 kernel/sched/core.c:3880 schedule+0x8f/0x260 kernel/sched/core.c:3944 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:4003 __mutex_lock_common kernel/locking/mutex.c:1007 [inline] __mutex_lock+0x8bf/0x1410 kernel/locking/mutex.c:1077 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1092 rtnl_lock+0x12/0x20 net/core/rtnetlink.c:72 addrconf_dad_work+0xa2/0xfc0 net/ipv6/addrconf.c:4032 process_one_work+0x85b/0x1640 kernel/workqueue.c:2269 worker_thread+0x85/0xb60 kernel/workqueue.c:2415 kthread+0x334/0x3f0 kernel/kthread.c:255 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352 INFO: task syz-executor.1:7339 blocked for more than 143 seconds. Not tainted 5.3.0-rc4 #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.1 D23856 7339 1 0x00000004 Call Trace: context_switch kernel/sched/core.c:3254 [inline] __schedule+0x719/0x1530 kernel/sched/core.c:3880 schedule+0x8f/0x260 kernel/sched/core.c:3944 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:4003 __mutex_lock_common kernel/locking/mutex.c:1007 [inline] __mutex_lock+0x8bf/0x1410 kernel/locking/mutex.c:1077 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1092 rtnl_lock net/core/rtnetlink.c:72 [inline] rtnetlink_rcv_msg+0x301/0x8f0 net/core/rtnetlink.c:5220 netlink_rcv_skb+0x13f/0x380 net/netlink/af_netlink.c:2477 rtnetlink_rcv+0x10/0x20 net/core/rtnetlink.c:5241 netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline] netlink_unicast+0x444/0x640 net/netlink/af_netlink.c:1328 netlink_sendmsg+0x75d/0xc40 net/netlink/af_netlink.c:1917 sock_sendmsg_nosec net/socket.c:637 [inline] sock_sendmsg+0xe6/0x110 net/socket.c:657 __sys_sendto+0x1f2/0x2e0 net/socket.c:1952 __do_sys_sendto net/socket.c:1964 [inline] __se_sys_sendto net/socket.c:1960 [inline] __x64_sys_sendto+0xdc/0x1a0 net/socket.c:1960 do_syscall_64+0xd6/0x550 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x411e93 Code: 0f 1f 80 00 00 00 00 bf 69 30 44 00 b9 08 00 00 00 48 89 ee f3 a6 74 1f bf 71 30 44 00 b9 0c 00 00 00 48 89 ee f3 a6 75 1e 48 03 40 1c 41 00 eb b3 0f 1f 44 00 00 48 c7 03 30 1c 41 00 eb a5 RSP: 002b:00007ffe82c02428 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000411e93 RDX: 0000000000000028 RSI: 0000000000a50070 RDI: 0000000000000003 RBP: 00007ffe82c02490 R08: 00007ffe82c02430 R09: 000000000000000c R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003 R13: 00007ffe82c027c0 R14: 0000000000000000 R15: 0000000000000006 INFO: task syz-executor.0:7341 blocked for more than 144 seconds. Not tainted 5.3.0-rc4 #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.0 D24456 7341 1 0x00000004 Call Trace: context_switch kernel/sched/core.c:3254 [inline] __schedule+0x719/0x1530 kernel/sched/core.c:3880 schedule+0x8f/0x260 kernel/sched/core.c:3944 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:4003 __mutex_lock_common kernel/locking/mutex.c:1007 [inline] __mutex_lock+0x8bf/0x1410 kernel/locking/mutex.c:1077 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1092 rtnl_lock net/core/rtnetlink.c:72 [inline] rtnetlink_rcv_msg+0x301/0x8f0 net/core/rtnetlink.c:5220 netlink_rcv_skb+0x13f/0x380 net/netlink/af_netlink.c:2477 rtnetlink_rcv+0x10/0x20 net/core/rtnetlink.c:5241 netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline] netlink_unicast+0x444/0x640 net/netlink/af_netlink.c:1328 netlink_sendmsg+0x75d/0xc40 net/netlink/af_netlink.c:1917 sock_sendmsg_nosec net/socket.c:637 [inline] sock_sendmsg+0xe6/0x110 net/socket.c:657 __sys_sendto+0x1f2/0x2e0 net/socket.c:1952 __do_sys_sendto net/socket.c:1964 [inline] __se_sys_sendto net/socket.c:1960 [inline] __x64_sys_sendto+0xdc/0x1a0 net/socket.c:1960 do_syscall_64+0xd6/0x550 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x411e93 Code: 0f 1f 80 00 00 00 00 bf 69 30 44 00 b9 08 00 00 00 48 89 ee f3 a6 74 1f bf 71 30 44 00 b9 0c 00 00 00 48 89 ee f3 a6 75 1e 48 03 40 1c 41 00 eb b3 0f 1f 44 00 00 48 c7 03 30 1c 41 00 eb a5 RSP: 002b:00007ffed6d2a158 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000411e93 RDX: 0000000000000028 RSI: 0000000000a50070 RDI: 0000000000000003 RBP: 00007ffed6d2a1c0 R08: 00007ffed6d2a160 R09: 000000000000000c R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003 R13: 00007ffed6d2a4f0 R14: 0000000000000000 R15: 0000000000000006 INFO: task syz-executor.5:7343 blocked for more than 144 seconds. Not tainted 5.3.0-rc4 #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.5 D24456 7343 1 0x00000004 Call Trace: context_switch kernel/sched/core.c:3254 [inline] __schedule+0x719/0x1530 kernel/sched/core.c:3880 schedule+0x8f/0x260 kernel/sched/core.c:3944 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:4003 __mutex_lock_common kernel/locking/mutex.c:1007 [inline] __mutex_lock+0x8bf/0x1410 kernel/locking/mutex.c:1077 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1092 rtnl_lock net/core/rtnetlink.c:72 [inline] rtnetlink_rcv_msg+0x301/0x8f0 net/core/rtnetlink.c:5220 netlink_rcv_skb+0x13f/0x380 net/netlink/af_netlink.c:2477 rtnetlink_rcv+0x10/0x20 net/core/rtnetlink.c:5241 netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline] netlink_unicast+0x444/0x640 net/netlink/af_netlink.c:1328 netlink_sendmsg+0x75d/0xc40 net/netlink/af_netlink.c:1917 sock_sendmsg_nosec net/socket.c:637 [inline] sock_sendmsg+0xe6/0x110 net/socket.c:657 __sys_sendto+0x1f2/0x2e0 net/socket.c:1952 __do_sys_sendto net/socket.c:1964 [inline] __se_sys_sendto net/socket.c:1960 [inline] __x64_sys_sendto+0xdc/0x1a0 net/socket.c:1960 do_syscall_64+0xd6/0x550 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x411e93 Code: 0f 1f 80 00 00 00 00 bf 69 30 44 00 b9 08 00 00 00 48 89 ee f3 a6 74 1f bf 71 30 44 00 b9 0c 00 00 00 48 89 ee f3 a6 75 1e 48 03 40 1c 41 00 eb b3 0f 1f 44 00 00 48 c7 03 30 1c 41 00 eb a5 RSP: 002b:00007fff856b7b08 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000411e93 RDX: 0000000000000028 RSI: 0000000000a50070 RDI: 0000000000000003 RBP: 00007fff856b7b70 R08: 00007fff856b7b10 R09: 000000000000000c R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003 R13: 00007fff856b7ea0 R14: 0000000000000000 R15: 0000000000000006 INFO: task syz-executor.3:7345 blocked for more than 145 seconds. Not tainted 5.3.0-rc4 #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.3 D24216 7345 1 0x00000004 Call Trace: context_switch kernel/sched/core.c:3254 [inline] __schedule+0x719/0x1530 kernel/sched/core.c:3880 schedule+0x8f/0x260 kernel/sched/core.c:3944 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:4003 __mutex_lock_common kernel/locking/mutex.c:1007 [inline] __mutex_lock+0x8bf/0x1410 kernel/locking/mutex.c:1077 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1092 rtnl_lock net/core/rtnetlink.c:72 [inline] rtnetlink_rcv_msg+0x301/0x8f0 net/core/rtnetlink.c:5220 netlink_rcv_skb+0x13f/0x380 net/netlink/af_netlink.c:2477 rtnetlink_rcv+0x10/0x20 net/core/rtnetlink.c:5241 netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline] netlink_unicast+0x444/0x640 net/netlink/af_netlink.c:1328 netlink_sendmsg+0x75d/0xc40 net/netlink/af_netlink.c:1917 sock_sendmsg_nosec net/socket.c:637 [inline] sock_sendmsg+0xe6/0x110 net/socket.c:657 __sys_sendto+0x1f2/0x2e0 net/socket.c:1952 __do_sys_sendto net/socket.c:1964 [inline] __se_sys_sendto net/socket.c:1960 [inline] __x64_sys_sendto+0xdc/0x1a0 net/socket.c:1960 do_syscall_64+0xd6/0x550 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x411e93 Code: 0f 1f 80 00 00 00 00 bf 69 30 44 00 b9 08 00 00 00 48 89 ee f3 a6 74 1f bf 71 30 44 00 b9 0c 00 00 00 48 89 ee f3 a6 75 1e 48 03 40 1c 41 00 eb b3 0f 1f 44 00 00 48 c7 03 30 1c 41 00 eb a5 RSP: 002b:00007ffcb12c26b8 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000411e93 RDX: 0000000000000028 RSI: 0000000000a50070 RDI: 0000000000000003 RBP: 00007ffcb12c2720 R08: 00007ffcb12c26c0 R09: 000000000000000c R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003 R13: 00007ffcb12c2a50 R14: 0000000000000000 R15: 0000000000000006 INFO: task syz-executor.4:7346 blocked for more than 145 seconds. Not tainted 5.3.0-rc4 #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.4 D24456 7346 1 0x00000004 Call Trace: context_switch kernel/sched/core.c:3254 [inline] __schedule+0x719/0x1530 kernel/sched/core.c:3880 schedule+0x8f/0x260 kernel/sched/core.c:3944 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:4003 __mutex_lock_common kernel/locking/mutex.c:1007 [inline] __mutex_lock+0x8bf/0x1410 kernel/locking/mutex.c:1077 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1092 rtnl_lock net/core/rtnetlink.c:72 [inline] rtnetlink_rcv_msg+0x301/0x8f0 net/core/rtnetlink.c:5220 netlink_rcv_skb+0x13f/0x380 net/netlink/af_netlink.c:2477 rtnetlink_rcv+0x10/0x20 net/core/rtnetlink.c:5241 netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline] netlink_unicast+0x444/0x640 net/netlink/af_netlink.c:1328 netlink_sendmsg+0x75d/0xc40 net/netlink/af_netlink.c:1917 sock_sendmsg_nosec net/socket.c:637 [inline] sock_sendmsg+0xe6/0x110 net/socket.c:657 __sys_sendto+0x1f2/0x2e0 net/socket.c:1952 __do_sys_sendto net/socket.c:1964 [inline] __se_sys_sendto net/socket.c:1960 [inline] __x64_sys_sendto+0xdc/0x1a0 net/socket.c:1960 do_syscall_64+0xd6/0x550 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x411e93 Code: 0f 1f 80 00 00 00 00 bf 69 30 44 00 b9 08 00 00 00 48 89 ee f3 a6 74 1f bf 71 30 44 00 b9 0c 00 00 00 48 89 ee f3 a6 75 1e 48 03 40 1c 41 00 eb b3 0f 1f 44 00 00 48 c7 03 30 1c 41 00 eb a5 RSP: 002b:00007ffd3a3582f8 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000411e93 RDX: 0000000000000028 RSI: 0000000000a50070 RDI: 0000000000000003 RBP: 00007ffd3a358360 R08: 00007ffd3a358300 R09: 000000000000000c R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003 R13: 00007ffd3a358690 R14: 0000000000000000 R15: 0000000000000006 INFO: task kworker/0:3:7349 blocked for more than 145 seconds. Not tainted 5.3.0-rc4 #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/0:3 D26944 7349 2 0x80004000 Workqueue: events switchdev_deferred_process_work Call Trace: context_switch kernel/sched/core.c:3254 [inline] __schedule+0x719/0x1530 kernel/sched/core.c:3880 schedule+0x8f/0x260 kernel/sched/core.c:3944 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:4003 __mutex_lock_common kernel/locking/mutex.c:1007 [inline] __mutex_lock+0x8bf/0x1410 kernel/locking/mutex.c:1077 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1092 rtnl_lock+0x12/0x20 net/core/rtnetlink.c:72 switchdev_deferred_process_work+0x9/0x20 net/switchdev/switchdev.c:74 process_one_work+0x85b/0x1640 kernel/workqueue.c:2269 worker_thread+0x85/0xb60 kernel/workqueue.c:2415 kthread+0x334/0x3f0 kernel/kthread.c:255 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352 Showing all locks held in the system: 3 locks held by kworker/1:0/17: #0: 00000000fd37984f ((wq_completion)events_power_efficient){+.+.}, at: __write_once_size include/linux/compiler.h:226 [inline] #0: 00000000fd37984f ((wq_completion)events_power_efficient){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: 00000000fd37984f ((wq_completion)events_power_efficient){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline] #0: 00000000fd37984f ((wq_completion)events_power_efficient){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline] #0: 00000000fd37984f ((wq_completion)events_power_efficient){+.+.}, at: set_work_data kernel/workqueue.c:620 [inline] #0: 00000000fd37984f ((wq_completion)events_power_efficient){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:647 [inline] #0: 00000000fd37984f ((wq_completion)events_power_efficient){+.+.}, at: process_one_work+0x76f/0x1640 kernel/workqueue.c:2240 #1: 0000000022830b2f ((reg_check_chans).work){+.+.}, at: process_one_work+0x79f/0x1640 kernel/workqueue.c:2244 #2: 000000006ae570e6 (rtnl_mutex){+.+.}, at: rtnl_lock+0x12/0x20 net/core/rtnetlink.c:72 1 lock held by khungtaskd/1051: #0: 00000000bf37dc94 (rcu_read_lock){....}, at: debug_show_all_locks+0x5b/0x27a kernel/locking/lockdep.c:5256 3 locks held by kworker/0:2/2964: #0: 00000000f2882d4b ((wq_completion)ipv6_addrconf){+.+.}, at: __write_once_size include/linux/compiler.h:226 [inline] #0: 00000000f2882d4b ((wq_completion)ipv6_addrconf){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: 00000000f2882d4b ((wq_completion)ipv6_addrconf){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline] #0: 00000000f2882d4b ((wq_completion)ipv6_addrconf){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline] #0: 00000000f2882d4b ((wq_completion)ipv6_addrconf){+.+.}, at: set_work_data kernel/workqueue.c:620 [inline] #0: 00000000f2882d4b ((wq_completion)ipv6_addrconf){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:647 [inline] #0: 00000000f2882d4b ((wq_completion)ipv6_addrconf){+.+.}, at: process_one_work+0x76f/0x1640 kernel/workqueue.c:2240 #1: 000000002359d985 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}, at: process_one_work+0x79f/0x1640 kernel/workqueue.c:2244 #2: 000000006ae570e6 (rtnl_mutex){+.+.}, at: rtnl_lock+0x12/0x20 net/core/rtnetlink.c:72 1 lock held by rsyslogd/7136: #0: 00000000ad52e679 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xa3/0xc0 fs/file.c:801 2 locks held by getty/7226: #0: 000000006c58885c (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x2d/0x40 drivers/tty/tty_ldsem.c:340 #1: 00000000036b3441 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x1ee/0x1930 drivers/tty/n_tty.c:2156 2 locks held by getty/7227: #0: 000000008c1d64bb (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x2d/0x40 drivers/tty/tty_ldsem.c:340 #1: 000000009a0f40c0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x1ee/0x1930 drivers/tty/n_tty.c:2156 2 locks held by getty/7228: #0: 000000003ba8c1b7 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x2d/0x40 drivers/tty/tty_ldsem.c:340 #1: 000000008c6f8ba4 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x1ee/0x1930 drivers/tty/n_tty.c:2156 2 locks held by getty/7229: #0: 00000000841c6f05 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x2d/0x40 drivers/tty/tty_ldsem.c:340 #1: 00000000b1e9a409 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x1ee/0x1930 drivers/tty/n_tty.c:2156 2 locks held by getty/7230: #0: 00000000db4343be (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x2d/0x40 drivers/tty/tty_ldsem.c:340 #1: 0000000098feb555 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x1ee/0x1930 drivers/tty/n_tty.c:2156 2 locks held by getty/7231: #0: 000000000f9a8fd3 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x2d/0x40 drivers/tty/tty_ldsem.c:340 #1: 00000000f137d671 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x1ee/0x1930 drivers/tty/n_tty.c:2156 2 locks held by getty/7232: #0: 000000007ddfc66f (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x2d/0x40 drivers/tty/tty_ldsem.c:340 #1: 00000000afae4f3a (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x1ee/0x1930 drivers/tty/n_tty.c:2156 3 locks held by kworker/1:3/7268: #0: 00000000f2882d4b ((wq_completion)ipv6_addrconf){+.+.}, at: __write_once_size include/linux/compiler.h:226 [inline] #0: 00000000f2882d4b ((wq_completion)ipv6_addrconf){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: 00000000f2882d4b ((wq_completion)ipv6_addrconf){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline] #0: 00000000f2882d4b ((wq_completion)ipv6_addrconf){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline] #0: 00000000f2882d4b ((wq_completion)ipv6_addrconf){+.+.}, at: set_work_data kernel/workqueue.c:620 [inline] #0: 00000000f2882d4b ((wq_completion)ipv6_addrconf){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:647 [inline] #0: 00000000f2882d4b ((wq_completion)ipv6_addrconf){+.+.}, at: process_one_work+0x76f/0x1640 kernel/workqueue.c:2240 #1: 000000007e7ac79f ((work_completion)(&(&ifa->dad_work)->work)){+.+.}, at: process_one_work+0x79f/0x1640 kernel/workqueue.c:2244 #2: 000000006ae570e6 (rtnl_mutex){+.+.}, at: rtnl_lock+0x12/0x20 net/core/rtnetlink.c:72 1 lock held by syz-executor.1/7339: #0: 000000006ae570e6 (rtnl_mutex){+.+.}, at: rtnl_lock net/core/rtnetlink.c:72 [inline] #0: 000000006ae570e6 (rtnl_mutex){+.+.}, at: rtnetlink_rcv_msg+0x301/0x8f0 net/core/rtnetlink.c:5220 1 lock held by syz-executor.0/7341: #0: 000000006ae570e6 (rtnl_mutex){+.+.}, at: rtnl_lock net/core/rtnetlink.c:72 [inline] #0: 000000006ae570e6 (rtnl_mutex){+.+.}, at: rtnetlink_rcv_msg+0x301/0x8f0 net/core/rtnetlink.c:5220 1 lock held by syz-executor.5/7343: #0: 000000006ae570e6 (rtnl_mutex){+.+.}, at: rtnl_lock net/core/rtnetlink.c:72 [inline] #0: 000000006ae570e6 (rtnl_mutex){+.+.}, at: rtnetlink_rcv_msg+0x301/0x8f0 net/core/rtnetlink.c:5220 1 lock held by syz-executor.3/7345: #0: 000000006ae570e6 (rtnl_mutex){+.+.}, at: rtnl_lock net/core/rtnetlink.c:72 [inline] #0: 000000006ae570e6 (rtnl_mutex){+.+.}, at: rtnetlink_rcv_msg+0x301/0x8f0 net/core/rtnetlink.c:5220 1 lock held by syz-executor.4/7346: #0: 000000006ae570e6 (rtnl_mutex){+.+.}, at: rtnl_lock net/core/rtnetlink.c:72 [inline] #0: 000000006ae570e6 (rtnl_mutex){+.+.}, at: rtnetlink_rcv_msg+0x301/0x8f0 net/core/rtnetlink.c:5220 3 locks held by kworker/0:3/7349: #0: 0000000024e2399b ((wq_completion)events){+.+.}, at: __write_once_size include/linux/compiler.h:226 [inline] #0: 0000000024e2399b ((wq_completion)events){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: 0000000024e2399b ((wq_completion)events){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline] #0: 0000000024e2399b ((wq_completion)events){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline] #0: 0000000024e2399b ((wq_completion)events){+.+.}, at: set_work_data kernel/workqueue.c:620 [inline] #0: 0000000024e2399b ((wq_completion)events){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:647 [inline] #0: 0000000024e2399b ((wq_completion)events){+.+.}, at: process_one_work+0x76f/0x1640 kernel/workqueue.c:2240 #1: 0000000000627ba3 (deferred_process_work){+.+.}, at: process_one_work+0x79f/0x1640 kernel/workqueue.c:2244 #2: 000000006ae570e6 (rtnl_mutex){+.+.}, at: rtnl_lock+0x12/0x20 net/core/rtnetlink.c:72 2 locks held by syz-executor.2/7366: ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1051 Comm: khungtaskd Not tainted 5.3.0-rc4 #1 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x113/0x167 lib/dump_stack.c:113 nmi_cpu_backtrace.cold.7+0x4b/0x84 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x18b/0x1b7 lib/nmi_backtrace.c:62 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:205 [inline] watchdog+0x592/0xb70 kernel/hung_task.c:289 kthread+0x334/0x3f0 kernel/kthread.c:255 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 21 Comm: kworker/u4:1 Not tainted 5.3.0-rc4 #1 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: bat_events batadv_nc_worker RIP: 0010:__lock_acquire+0xb8d/0x4b70 kernel/locking/lockdep.c:3753 Code: 2b 00 00 48 81 c4 00 01 00 00 5b 41 5c 41 5d 41 5e 41 5f 5d c3 48 b8 00 00 00 00 00 fc ff df 4c 89 ea 48 c1 ea 03 80 3c 02 00 <0f> 85 cf 2e 00 00 49 81 7d 00 60 b6 32 89 0f 84 2d f5 ff ff 83 fe RSP: 0018:ffff8880a9a2fac0 EFLAGS: 00000046 RAX: dffffc0000000000 RBX: 0000000000000001 RCX: 0000000000000000 RDX: 1ffff11011d56d85 RSI: 0000000000000000 RDI: ffff88808eab6c28 RBP: ffff8880a9a2fbe8 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: ffff8880a9a1c580 R12: 0000000000000000 R13: ffff88808eab6c28 R14: 0000000000000000 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8880aeb00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000014c3000 CR3: 00000000a86c1000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lock_acquire+0x194/0x410 kernel/locking/lockdep.c:4412 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:135 [inline] _raw_spin_lock_bh+0x31/0x40 kernel/locking/spinlock.c:175 spin_lock_bh include/linux/spinlock.h:343 [inline] batadv_nc_purge_paths+0xc0/0x300 net/batman-adv/network-coding.c:441 batadv_nc_worker+0x1f3/0x630 net/batman-adv/network-coding.c:719 process_one_work+0x85b/0x1640 kernel/workqueue.c:2269 worker_thread+0x85/0xb60 kernel/workqueue.c:2415 kthread+0x334/0x3f0 kernel/kthread.c:255 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352