syzbot

INFO: task syz-executor446:6822 blocked for more than 143 seconds.
      Not tainted 5.8.0-rc3-next-20200701-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor446 D27632  6822   6816 0x00004000
Call Trace:
 context_switch kernel/sched/core.c:3445 [inline]
 __schedule+0x8b4/0x1e80 kernel/sched/core.c:4169
 schedule+0xd0/0x2a0 kernel/sched/core.c:4244
 bit_wait+0x12/0xa0 kernel/sched/wait_bit.c:199
 __wait_on_bit+0x60/0x190 kernel/sched/wait_bit.c:49
 out_of_line_wait_on_bit+0xd5/0x110 kernel/sched/wait_bit.c:64
 wait_on_bit include/linux/wait_bit.h:76 [inline]
 wait_for_key_construction+0x10b/0x140 security/keys/request_key.c:664
 request_key_tag+0x7a/0xb0 security/keys/request_key.c:705
 dns_query+0x257/0x6c3 net/dns_resolver/dns_query.c:128
 ceph_dns_resolve_name net/ceph/messenger.c:1887 [inline]
 ceph_parse_server_name net/ceph/messenger.c:1922 [inline]
 ceph_parse_ips+0x77f/0x8c0 net/ceph/messenger.c:1949
 ceph_parse_mon_ips+0x59/0xc0 net/ceph/ceph_common.c:411
 ceph_parse_source fs/ceph/super.c:271 [inline]
 ceph_parse_mount_param+0x1239/0x17e0 fs/ceph/super.c:322
 vfs_parse_fs_param fs/fs_context.c:117 [inline]
 vfs_parse_fs_param+0x203/0x550 fs/fs_context.c:98
 vfs_parse_fs_string+0xe6/0x150 fs/fs_context.c:161
 do_new_mount fs/namespace.c:2905 [inline]
 do_mount+0x1222/0x1df0 fs/namespace.c:3237
 __do_sys_mount fs/namespace.c:3447 [inline]
 __se_sys_mount fs/namespace.c:3424 [inline]
 __x64_sys_mount+0x18f/0x230 fs/namespace.c:3424
 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:359
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x4401b9
Code: Bad RIP value.
RSP: 002b:00007ffcf5f97f68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 0030656c69662f2e RCX: 00000000004401b9
RDX: 0000000020000040 RSI: 0000000020000080 RDI: 00000000200002c0
RBP: 00000000006ca018 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000401a40
R13: 0000000000401ad0 R14: 0000000000000000 R15: 0000000000000000

Showing all locks held in the system:
1 lock held by khungtaskd/1150:
 #0: ffffffff89bc3000 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:5779

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

NMI backtrace for cpu 1
CPU: 1 PID: 1150 Comm: khungtaskd Not tainted 5.8.0-rc3-next-20200701-syzkaller #0
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+0x18f/0x20d lib/dump_stack.c:118
 nmi_cpu_backtrace.cold+0x70/0xb1 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x1b3/0x223 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:147 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:253 [inline]
 watchdog+0xd89/0xf30 kernel/hung_task.c:339
 kthread+0x3b5/0x4a0 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 3872 Comm: systemd-journal Not tainted 5.8.0-rc3-next-20200701-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:ep_item_poll+0x18f/0x3e0 fs/eventpoll.c:896
Code: 04 02 84 c0 74 08 3c 03 0f 8e ce 01 00 00 44 23 63 70 e8 d4 e8 a1 ff 48 b8 00 00 00 00 00 fc ff df 49 c7 44 05 00 00 00 00 00 <48> 8b 44 24 68 65 48 2b 04 25 28 00 00 00 0f 85 dc 01 00 00 48 83
RSP: 0018:ffffc90001577b00 EFLAGS: 00000293
RAX: dffffc0000000000 RBX: ffff888094b7ec00 RCX: 0000000000000006
RDX: ffff88809371e240 RSI: ffffffff81d2029c RDI: ffffffff815cf492
RBP: ffffc90001577c30 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000001
R13: 1ffff920002aef62 R14: ffff888094b7ec70 R15: ffffffff815cf360
FS:  00007f577ad1e8c0(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f57780bd000 CR3: 0000000093aca000 CR4: 00000000001506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 ep_send_events_proc+0x272/0xc50 fs/eventpoll.c:1744
 ep_scan_ready_list+0x28f/0x880 fs/eventpoll.c:714
 ep_send_events fs/eventpoll.c:1788 [inline]
 ep_poll fs/eventpoll.c:1944 [inline]
 do_epoll_wait+0xac4/0x1190 fs/eventpoll.c:2333
 __do_sys_epoll_wait fs/eventpoll.c:2343 [inline]
 __se_sys_epoll_wait fs/eventpoll.c:2340 [inline]
 __x64_sys_epoll_wait+0x93/0xf0 fs/eventpoll.c:2340
 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:359
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x7f5779fe82e3
Code: Bad RIP value.
RSP: 002b:00007fffb50ab0c8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e8
RAX: ffffffffffffffda RBX: 0000555bedae41e0 RCX: 00007f5779fe82e3
RDX: 0000000000000013 RSI: 00007fffb50ab0d0 RDI: 0000000000000008
RBP: 00007fffb50ab2c0 R08: 0000555bedae60b0 R09: 00007fffb510c080
R10: 00000000ffffffff R11: 0000000000000246 R12: 00007fffb50ab0d0
R13: 0000000000000001 R14: ffffffffffffffff R15: 0005a989a2695dae