INFO: task syz-executor.2:4027 blocked for more than 143 seconds. Not tainted 5.6.0-rc5-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.2 D28000 4027 9800 0x20024004 Call Trace: schedule+0xd0/0x2a0 kernel/sched/core.c:4154 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:4213 __mutex_lock_common kernel/locking/mutex.c:1033 [inline] __mutex_lock+0x7ab/0x13c0 kernel/locking/mutex.c:1103 nfnl_lock net/netfilter/nfnetlink.c:62 [inline] nfnetlink_rcv_msg+0x9a6/0xf30 net/netfilter/nfnetlink.c:224 netlink_rcv_skb+0x15a/0x410 net/netlink/af_netlink.c:2478 nfnetlink_rcv+0x1ac/0x420 net/netfilter/nfnetlink.c:563 netlink_unicast_kernel net/netlink/af_netlink.c:1303 [inline] netlink_unicast+0x537/0x740 net/netlink/af_netlink.c:1329 netlink_sendmsg+0x882/0xe10 net/netlink/af_netlink.c:1918 sock_sendmsg_nosec net/socket.c:652 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:672 ____sys_sendmsg+0x6b9/0x7d0 net/socket.c:2343 ___sys_sendmsg+0x100/0x170 net/socket.c:2397 __sys_sendmsg+0xec/0x1b0 net/socket.c:2430 do_syscall_32_irqs_on arch/x86/entry/common.c:337 [inline] do_fast_syscall_32+0x270/0xe8f arch/x86/entry/common.c:408 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139 Showing all locks held in the system: 1 lock held by khungtaskd/1134: #0: ffffffff897accc0 (rcu_read_lock){....}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:5331 1 lock held by rsyslogd/9659: #0: ffff8880904c61a0 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xe3/0x100 fs/file.c:821 2 locks held by getty/9749: #0: ffff88809fedb090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc900017db2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21d/0x1b30 drivers/tty/n_tty.c:2156 2 locks held by getty/9750: #0: ffff88809cf04090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc900017eb2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21d/0x1b30 drivers/tty/n_tty.c:2156 2 locks held by getty/9751: #0: ffff88809e1da090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc900017fb2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21d/0x1b30 drivers/tty/n_tty.c:2156 2 locks held by getty/9752: #0: ffff8880a69e1090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc900017c32e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21d/0x1b30 drivers/tty/n_tty.c:2156 2 locks held by getty/9753: #0: ffff8880a4c0f090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc9000179b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21d/0x1b30 drivers/tty/n_tty.c:2156 2 locks held by getty/9754: #0: ffff8880a6d82090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc9000176b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21d/0x1b30 drivers/tty/n_tty.c:2156 2 locks held by getty/9755: #0: ffff8880a4ebb090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc9000174b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21d/0x1b30 drivers/tty/n_tty.c:2156 3 locks held by syz-executor.2/3903: 1 lock held by syz-executor.2/4027: #0: ffffffff8cf4a810 (&table[i].mutex){+.+.}, at: nfnl_lock net/netfilter/nfnetlink.c:62 [inline] #0: ffffffff8cf4a810 (&table[i].mutex){+.+.}, at: nfnetlink_rcv_msg+0x9a6/0xf30 net/netfilter/nfnetlink.c:224 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1134 Comm: khungtaskd Not tainted 5.6.0-rc5-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+0x188/0x20d lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x70/0xb1 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x231/0x27e lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:205 [inline] watchdog+0xa8c/0x1010 kernel/hung_task.c:289 kthread+0x357/0x430 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 3903 Comm: syz-executor.2 Not tainted 5.6.0-rc5-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:__lock_acquire+0x908/0x3ca0 kernel/locking/lockdep.c:3958 Code: 00 0f 85 e4 29 00 00 48 8b 44 24 30 48 8b 54 24 20 48 89 85 88 08 00 00 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 0f b6 04 02 <84> c0 74 08 3c 03 0f 8e b8 10 00 00 8b 85 90 08 00 00 83 c0 01 83 RSP: 0018:ffffc90016736ee0 EFLAGS: 00000806 RAX: 0000000000000000 RBX: ffffffff8c074d50 RCX: ffffffff815847fb RDX: 1ffff1100b81556a RSI: 0000000000000008 RDI: ffffffff8c074d90 RBP: ffff88805c0aa2c0 R08: 0000000000000000 R09: fffffbfff180e575 R10: fffffbfff180e574 R11: ffffffff8c072ba7 R12: 0000000099cb16ac R13: e9344ec7ea5f644a R14: ffffffff8a660390 R15: ffff88805c0aaba8 FS: 0000000000000000(0000) GS:ffff8880ae600000(0063) knlGS:00000000f5d14b40 CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033 CR2: ffffffffff600400 CR3: 000000008e116000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lock_acquire+0x197/0x420 kernel/locking/lockdep.c:4484 rcu_lock_acquire include/linux/rcupdate.h:208 [inline] rcu_read_lock include/linux/rcupdate.h:601 [inline] cond_resched_rcu include/linux/sched.h:1800 [inline] hash_netnet4_list+0x336/0x1330 net/netfilter/ipset/ip_set_hash_gen.h:1369 ip_set_dump_do+0xca8/0x1970 net/netfilter/ipset/ip_set_core.c:1646 netlink_dump+0x515/0xf30 net/netlink/af_netlink.c:2245 __netlink_dump_start+0x648/0x910 net/netlink/af_netlink.c:2353 netlink_dump_start include/linux/netlink.h:233 [inline] ip_set_dump+0x133/0x1a0 net/netfilter/ipset/ip_set_core.c:1705 nfnetlink_rcv_msg+0xc83/0xf30 net/netfilter/nfnetlink.c:229 netlink_rcv_skb+0x15a/0x410 net/netlink/af_netlink.c:2478 nfnetlink_rcv+0x1ac/0x420 net/netfilter/nfnetlink.c:563 netlink_unicast_kernel net/netlink/af_netlink.c:1303 [inline] netlink_unicast+0x537/0x740 net/netlink/af_netlink.c:1329 netlink_sendmsg+0x882/0xe10 net/netlink/af_netlink.c:1918 sock_sendmsg_nosec net/socket.c:652 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:672 ____sys_sendmsg+0x6b9/0x7d0 net/socket.c:2343 ___sys_sendmsg+0x100/0x170 net/socket.c:2397 __sys_sendmsg+0xec/0x1b0 net/socket.c:2430 do_syscall_32_irqs_on arch/x86/entry/common.c:337 [inline] do_fast_syscall_32+0x270/0xe8f arch/x86/entry/common.c:408 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139