INFO: task syz-executor237:7988 blocked for more than 140 seconds. Not tainted 4.14.218-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor237 D27592 7988 7985 0x00000004 Call Trace: context_switch syzkaller/managers/linux-4-14/kernel/kernel/sched/core.c:2808 [inline] __schedule+0x88b/0x1de0 syzkaller/managers/linux-4-14/kernel/kernel/sched/core.c:3384 schedule+0x8d/0x1b0 syzkaller/managers/linux-4-14/kernel/kernel/sched/core.c:3428 schedule_timeout+0x80a/0xe90 syzkaller/managers/linux-4-14/kernel/kernel/time/timer.c:1724 do_wait_for_common syzkaller/managers/linux-4-14/kernel/kernel/sched/completion.c:91 [inline] __wait_for_common syzkaller/managers/linux-4-14/kernel/kernel/sched/completion.c:112 [inline] wait_for_common+0x272/0x430 syzkaller/managers/linux-4-14/kernel/kernel/sched/completion.c:123 flush_work+0x3fe/0x770 syzkaller/managers/linux-4-14/kernel/kernel/workqueue.c:2893 __cancel_work_timer+0x321/0x460 syzkaller/managers/linux-4-14/kernel/kernel/workqueue.c:2964 p9_conn_destroy syzkaller/managers/linux-4-14/kernel/net/9p/trans_fd.c:898 [inline] p9_fd_close+0x28d/0x420 syzkaller/managers/linux-4-14/kernel/net/9p/trans_fd.c:925 p9_client_create+0x736/0x12c0 syzkaller/managers/linux-4-14/kernel/net/9p/client.c:1095 v9fs_session_init+0x1c5/0x1540 syzkaller/managers/linux-4-14/kernel/fs/9p/v9fs.c:422 v9fs_mount+0x73/0x860 syzkaller/managers/linux-4-14/kernel/fs/9p/vfs_super.c:135 mount_fs+0x92/0x2a0 syzkaller/managers/linux-4-14/kernel/fs/super.c:1237 vfs_kern_mount.part.0+0x5b/0x470 syzkaller/managers/linux-4-14/kernel/fs/namespace.c:1046 vfs_kern_mount syzkaller/managers/linux-4-14/kernel/fs/namespace.c:1036 [inline] do_new_mount syzkaller/managers/linux-4-14/kernel/fs/namespace.c:2549 [inline] do_mount+0xe53/0x2a00 syzkaller/managers/linux-4-14/kernel/fs/namespace.c:2879 SYSC_mount syzkaller/managers/linux-4-14/kernel/fs/namespace.c:3095 [inline] SyS_mount+0xa8/0x120 syzkaller/managers/linux-4-14/kernel/fs/namespace.c:3072 do_syscall_64+0x1d5/0x640 syzkaller/managers/linux-4-14/kernel/arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x44a249 RSP: 002b:00007f86bc092278 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 00000000004cb510 RCX: 000000000044a249 RDX: 0000000020000080 RSI: 0000000020000300 RDI: 0000000000000000 RBP: 000000000049b0bc R08: 0000000020000740 R09: 65732f636f72702f R10: 0000000000000000 R11: 0000000000000246 R12: 00007f86bc092280 R13: 7277732f7665642f R14: 64663d736e617274 R15: 00000000004cb518 Showing all locks held in the system: 1 lock held by khungtaskd/1531: #0: (tasklist_lock){.+.+}, at: [] debug_show_all_locks+0x7c/0x21a syzkaller/managers/linux-4-14/kernel/kernel/locking/lockdep.c:4548 2 locks held by kworker/0:2/3623: #0: ("events"){+.+.}, at: [] process_one_work+0x6b0/0x14a0 syzkaller/managers/linux-4-14/kernel/kernel/workqueue.c:2087 #1: ((&m->rq)){+.+.}, at: [] process_one_work+0x6e6/0x14a0 syzkaller/managers/linux-4-14/kernel/kernel/workqueue.c:2091 1 lock held by in:imklog/7706: #0: (&f->f_pos_lock){+.+.}, at: [] __fdget_pos+0x1fb/0x2b0 syzkaller/managers/linux-4-14/kernel/fs/file.c:769 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1531 Comm: khungtaskd Not tainted 4.14.218-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack syzkaller/managers/linux-4-14/kernel/lib/dump_stack.c:17 [inline] dump_stack+0x1b2/0x281 syzkaller/managers/linux-4-14/kernel/lib/dump_stack.c:58 nmi_cpu_backtrace.cold+0x57/0x93 syzkaller/managers/linux-4-14/kernel/lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x13a/0x180 syzkaller/managers/linux-4-14/kernel/lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace syzkaller/managers/linux-4-14/kernel/./include/linux/nmi.h:140 [inline] check_hung_uninterruptible_tasks syzkaller/managers/linux-4-14/kernel/kernel/hung_task.c:195 [inline] watchdog+0x5b9/0xb40 syzkaller/managers/linux-4-14/kernel/kernel/hung_task.c:274 kthread+0x30d/0x420 syzkaller/managers/linux-4-14/kernel/kernel/kthread.c:232 ret_from_fork+0x24/0x30 syzkaller/managers/linux-4-14/kernel/arch/x86/entry/entry_64.S:404 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 4610 Comm: systemd-journal Not tainted 4.14.218-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff8880a1e404c0 task.stack: ffff8880a1e48000 RIP: 0010:preempt_count_add+0x20/0x170 syzkaller/managers/linux-4-14/kernel/kernel/sched/core.c:3099 RSP: 0018:ffff8880a1e4fa58 EFLAGS: 00000802 RAX: dffffc0000000000 RBX: ffffffff8beb4d40 RCX: 0000000000000001 RDX: 0000000000000004 RSI: 0000000000000001 RDI: 0000000000000001 RBP: 0000000000000001 R08: 000000000255ec80 R09: 0000000000000001 R10: 0000000000000000 R11: ffff8880a1e404c0 R12: fffffffffffffffe R13: 0000000000000001 R14: ffffea0002c43aa0 R15: ffffea0002c43a80 FS: 00007ff2500e78c0(0000) GS:ffff8880ba500000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ff24d4b9000 CR3: 00000000a1e7b000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: mod_lruvec_page_state syzkaller/managers/linux-4-14/kernel/./include/linux/memcontrol.h:633 [inline] kmem_freepages.isra.0+0x20b/0x3e0 syzkaller/managers/linux-4-14/kernel/mm/slab.c:1455 slab_destroy syzkaller/managers/linux-4-14/kernel/mm/slab.c:1723 [inline] slabs_destroy+0x90/0xd0 syzkaller/managers/linux-4-14/kernel/mm/slab.c:1739 cache_flusharray syzkaller/managers/linux-4-14/kernel/mm/slab.c:3483 [inline] ___cache_free+0x213/0x2c0 syzkaller/managers/linux-4-14/kernel/mm/slab.c:3525 qlink_free syzkaller/managers/linux-4-14/kernel/mm/kasan/quarantine.c:147 [inline] qlist_free_all+0x79/0x140 syzkaller/managers/linux-4-14/kernel/mm/kasan/quarantine.c:166 quarantine_reduce+0x185/0x200 syzkaller/managers/linux-4-14/kernel/mm/kasan/quarantine.c:259 kasan_kmalloc+0xa2/0x160 syzkaller/managers/linux-4-14/kernel/mm/kasan/kasan.c:536 slab_post_alloc_hook syzkaller/managers/linux-4-14/kernel/mm/slab.h:442 [inline] slab_alloc syzkaller/managers/linux-4-14/kernel/mm/slab.c:3390 [inline] kmem_cache_alloc+0x111/0x3c0 syzkaller/managers/linux-4-14/kernel/mm/slab.c:3550 prepare_creds+0x39/0x490 syzkaller/managers/linux-4-14/kernel/kernel/cred.c:255 SYSC_faccessat syzkaller/managers/linux-4-14/kernel/fs/open.c:365 [inline] SyS_faccessat+0x7b/0x680 syzkaller/managers/linux-4-14/kernel/fs/open.c:353 do_syscall_64+0x1d5/0x640 syzkaller/managers/linux-4-14/kernel/arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x7ff24f3a39c7 RSP: 002b:00007ffd91cc54f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000015 RAX: ffffffffffffffda RBX: 00007ffd91cc8410 RCX: 00007ff24f3a39c7 RDX: 00007ff24fe14a00 RSI: 0000000000000000 RDI: 000055aae901a9a3 RBP: 00007ffd91cc5530 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000069 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007ffd91cc8410 R15: 00007ffd91cc5a20 Code: ff 66 2e 0f 1f 84 00 00 00 00 00 48 b8 00 00 00 00 00 fc ff df 55 89 fd 53 48 c7 c3 40 4d eb 8b 48 89 da 48 c1 ea 03 0f b6 14 02 <48> 89 d8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 11 01 00 00