INFO: task syz-executor.4:20840 blocked for more than 140 seconds. Not tainted 4.14.198-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.4 D28912 20840 6372 0x00000004 Call Trace: context_switch kernel/sched/core.c:2808 [inline] __schedule+0x88b/0x1de0 kernel/sched/core.c:3384 schedule+0x8d/0x1b0 kernel/sched/core.c:3428 schedule_timeout+0x80a/0xe90 kernel/time/timer.c:1731 do_wait_for_common kernel/sched/completion.c:91 [inline] __wait_for_common kernel/sched/completion.c:112 [inline] wait_for_common+0x272/0x430 kernel/sched/completion.c:123 ucma_close+0xfc/0x340 drivers/infiniband/core/ucma.c:1749 __fput+0x25f/0x7a0 fs/file_table.c:210 task_work_run+0x11f/0x190 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:191 [inline] exit_to_usermode_loop+0x1ad/0x200 arch/x86/entry/common.c:164 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline] syscall_return_slowpath arch/x86/entry/common.c:270 [inline] do_syscall_64+0x4a3/0x640 arch/x86/entry/common.c:297 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x4177b1 RSP: 002b:00007fff1c6e0250 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000004 RCX: 00000000004177b1 RDX: 0000001b31920000 RSI: 000000000000086e RDI: 0000000000000003 RBP: 0000000000000001 R08: 00000000216a486e R09: 00000000216a4872 R10: 00007fff1c6e0330 R11: 0000000000000293 R12: ffffffffffffffff R13: 000000000033c791 R14: 00000000000003e8 R15: 000000000118bf2c Showing all locks held in the system: 1 lock held by khungtaskd/1068: #0: (tasklist_lock){.+.+}, at: [] debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4548 2 locks held by systemd-journal/3640: #0: (&rq->lock){-.-.}, at: [] rq_lock kernel/sched/sched.h:1747 [inline] #0: (&rq->lock){-.-.}, at: [] __schedule+0x1df/0x1de0 kernel/sched/core.c:3321 #1: (&mm->mmap_sem){++++}, at: [] __might_fault+0xd4/0x1b0 mm/memory.c:4583 1 lock held by in:imklog/6027: #0: (&f->f_pos_lock){+.+.}, at: [] __fdget_pos+0x1fb/0x2b0 fs/file.c:769 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1068 Comm: khungtaskd Not tainted 4.14.198-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x1b2/0x283 lib/dump_stack.c:58 nmi_cpu_backtrace.cold+0x57/0x93 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x13a/0x17f lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:140 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:195 [inline] watchdog+0x5b9/0xb40 kernel/hung_task.c:274 kthread+0x30d/0x420 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 63 Comm: kworker/u4:2 Not tainted 4.14.198-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: phy2 ieee80211_iface_work task: ffff8880a9458240 task.stack: ffff8880a9460000 RIP: 0010:cfg80211_find_ie_match+0x135/0x1d0 net/wireless/scan.c:498 RSP: 0018:ffff8880a9467398 EFLAGS: 00000297 RAX: 0000000000000000 RBX: 0000000000000006 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffff88808957b79e R08: 0000000000000000 R09: 0000000000000000 R10: ffff8880a9458b40 R11: ffff8880a9458240 R12: 0000000000000006 R13: dffffc0000000000 R14: ffff88808957b79f R15: ffff88808957b79d FS: 0000000000000000(0000) GS:ffff8880aea00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f1a62d46000 CR3: 00000000a8608000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: cfg80211_find_ie include/net/cfg80211.h:4444 [inline] cmp_bss.part.0+0x1a8/0x7b0 net/wireless/scan.c:612 cmp_bss net/wireless/scan.c:797 [inline] rb_find_bss.isra.0+0x14c/0x1e0 net/wireless/scan.c:797 cfg80211_bss_update+0x122/0x21c0 net/wireless/scan.c:903 cfg80211_inform_bss_frame_data+0x5db/0xd90 net/wireless/scan.c:1278 ieee80211_bss_info_update+0x340/0x1560 net/mac80211/scan.c:102 ieee80211_rx_bss_info net/mac80211/ibss.c:1125 [inline] ieee80211_rx_mgmt_probe_beacon+0xa6b/0x1450 net/mac80211/ibss.c:1607 ieee80211_ibss_rx_queued_mgmt+0xc0c/0x1680 net/mac80211/ibss.c:1634 ieee80211_iface_work+0x40c/0x770 net/mac80211/iface.c:1362 process_one_work+0x793/0x14a0 kernel/workqueue.c:2116 worker_thread+0x5cc/0xff0 kernel/workqueue.c:2250 kthread+0x30d/0x420 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 Code: 07 0f 85 6d ff ff ff e8 ca 01 6b fb 44 39 64 24 10 0f 8f 5d ff ff ff e8 ba 01 6b fb 48 63 44 24 14 48 8b 54 24 20 48 8b 74 24 18 <49> 8d 7c 06 fe e8 d1 be 60 00 85 c0 74 58 e8 98 01 6b fb 48 89