INFO: task hung in rtnetlink

Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
android-49	INFO: task hung in rtnetlink_rcv	syz			1	1835d	1832d	0/3	public: reported syz repro on 2019/04/14 09:28
IPv4: Oversized IP packet from 127.0.0.1
INFO: task syz-executor1:10536 blocked for more than 120 seconds.
      Not tainted 4.4.125-g38f41ec #21
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor1   D ffff8801cbe6f798 27048 10536   3808 0x20020004
 ffff8801cbe6f798 ffff8800b7aa1800 0000000000000000 0000000000000007
 ffff8800b7aa1800 ffff8801db31fdb8 ffff8801db31fde0 ffff8801db31f4d8
 ffff8801db31f4c0 ffff8801d79eb000 ffff8800b7aa1800 0000000000000000
Call Trace:
 [<ffffffff8376b82a>] schedule+0x7a/0x1b0 kernel/sched/core.c:3359
 [<ffffffff8376c023>] schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3392
 [<ffffffff837705e6>] __mutex_lock_common kernel/locking/mutex.c:582 [inline]
 [<ffffffff837705e6>] mutex_lock_nested+0x306/0x850 kernel/locking/mutex.c:621
 [<ffffffff82e8adcb>] rtnl_lock net/core/rtnetlink.c:70 [inline]
 [<ffffffff82e8adcb>] rtnetlink_rcv+0x1b/0x40 net/core/rtnetlink.c:3429
 [<ffffffff82f8fd82>] netlink_unicast_kernel net/netlink/af_netlink.c:1267 [inline]
 [<ffffffff82f8fd82>] netlink_unicast+0x522/0x760 net/netlink/af_netlink.c:1293
 [<ffffffff82f908a8>] netlink_sendmsg+0x8e8/0xc50 net/netlink/af_netlink.c:1847
 [<ffffffff82df168a>] sock_sendmsg_nosec net/socket.c:625 [inline]
 [<ffffffff82df168a>] sock_sendmsg+0xca/0x110 net/socket.c:635
 [<ffffffff82df3261>] ___sys_sendmsg+0x6c1/0x7c0 net/socket.c:1962
 [<ffffffff82df52b3>] __sys_sendmsg+0xd3/0x190 net/socket.c:1996
 [<ffffffff82ee01fa>] C_SYSC_sendmsg net/compat.c:720 [inline]
 [<ffffffff82ee01fa>] compat_SyS_sendmsg+0x2a/0x40 net/compat.c:718
 [<ffffffff81006d91>] do_syscall_32_irqs_on arch/x86/entry/common.c:392 [inline]
 [<ffffffff81006d91>] do_fast_syscall_32+0x321/0x8a0 arch/x86/entry/common.c:459
 [<ffffffff8377b2aa>] sysenter_flags_fixed+0xd/0x17
1 lock held by syz-executor1/10536:
 #0:  (rtnl_mutex){+.+.+.}, at: [<ffffffff82e8adcb>] rtnl_lock net/core/rtnetlink.c:70 [inline]
 #0:  (rtnl_mutex){+.+.+.}, at: [<ffffffff82e8adcb>] rtnetlink_rcv+0x1b/0x40 net/core/rtnetlink.c:3429
Sending NMI to all CPUs:
NMI backtrace for cpu 0
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.4.125-g38f41ec #21
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffffffff84217840 task.stack: ffffffff84200000
RIP: 0010:[<ffffffff81195990>]  [<ffffffff81195990>] atomic_notifier_call_chain+0x0/0x140 include/linux/rcupdate.h:913
RSP: 0018:ffffffff84207e00  EFLAGS: 00000246
RAX: ffffffff84217840 RBX: 0000000000000002 RCX: ffffffff8112e1fd
RDX: 0000000000000000 RSI: 0000000000000002 RDI: ffffffff84283ba0
RBP: ffffffff84207e10 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff847dec48
R13: fffffbfff07088c0 R14: ffffffff847ecfb8 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f9dddbf8000 CR3: 00000001c9092000 CR4: 0000000000160670
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffffffff8112e20e dffffc0000000000 ffffffff84207e20 ffffffff8102937f
 ffffffff84207ed0 ffffffff81221cb5 fffffbfff08fda06 ffffffff83778f3a
 0000000000000000 0000000041b58ab3 ffffffff83fa3583 ffffffff81221a50
Call Trace:
 [<ffffffff8102937f>] __exit_idle arch/x86/kernel/process.c:247 [inline]
 [<ffffffff8102937f>] arch_cpu_idle_exit+0x1f/0x30 arch/x86/kernel/process.c:268
 [<ffffffff81221cb5>] cpu_idle_loop kernel/sched/idle.c:255 [inline]
 [<ffffffff81221cb5>] cpu_startup_entry+0x265/0x8f0 kernel/sched/idle.c:301
 [<ffffffff837667b9>] rest_init+0x189/0x190 init/main.c:410
 [<ffffffff84823811>] start_kernel+0x6b9/0x6ee init/main.c:682
 [<ffffffff84822312>] x86_64_start_reservations+0x2a/0x2c arch/x86/kernel/head64.c:196
 [<ffffffff84822454>] x86_64_start_kernel+0x140/0x163 arch/x86/kernel/head64.c:185
Code: be 92 03 00 00 48 c7 c7 40 dc 84 83 c6 05 30 5f 64 03 01 e8 13 e3 09 00 e9 5a ff ff ff 0f 1f 40 00 66 2e 0f 1f 84 00 00 00 00 00 <55> 48 89 e5 41 55 49 89 d5 41 54 49 89 f4 53 48 89 fb 48 83 ec 
NMI backtrace for cpu 1
CPU: 1 PID: 486 Comm: khungtaskd Not tainted 4.4.125-g38f41ec #21
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8800bacfe000 task.stack: ffff8800bad00000
RIP: 0010:[<ffffffff810c3f87>]  [<ffffffff810c3f87>] native_apic_mem_write arch/x86/include/asm/apic.h:94 [inline]
RIP: 0010:[<ffffffff810c3f87>]  [<ffffffff810c3f87>] __default_send_IPI_dest_field arch/x86/include/asm/ipi.h:119 [inline]
RIP: 0010:[<ffffffff810c3f87>]  [<ffffffff810c3f87>] _flat_send_IPI_mask arch/x86/kernel/apic/apic_flat_64.c:61 [inline]
RIP: 0010:[<ffffffff810c3f87>]  [<ffffffff810c3f87>] flat_send_IPI_mask+0xf7/0x1a0 arch/x86/kernel/apic/apic_flat_64.c:69
RSP: 0018:ffff8800bad07cb8  EFLAGS: 00000046
RAX: 0000000003000000 RBX: 0000000000000c00 RCX: 0000000000000000
RDX: 0000000000000c00 RSI: 0000000000000000 RDI: ffffffffff5fb300
RBP: ffff8800bad07ce0 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000246
R13: 0000000000000003 R14: ffffffff8426f5a0 R15: 0000000000000002
FS:  0000000000000000(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffa1a570140 CR3: 00000001c9092000 CR4: 0000000000160670
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffffffff8426f5a0 ffffffff847f0b40 fffffbfff08fdc1c dffffc0000000000
 ffff8801db31bca0 ffff8800bad07d00 ffffffff810b9abb ffffffff839f6dc0
 0000000000000003 ffff8800bad07d60 ffffffff81d11764 ffffffff8141b993
Call Trace:
 [<ffffffff810b9abb>] nmi_raise_cpu_backtrace+0x5b/0x70 arch/x86/kernel/apic/hw_nmi.c:33
 [<ffffffff81d11764>] nmi_trigger_all_cpu_backtrace+0x4a4/0x550 lib/nmi_backtrace.c:85
 [<ffffffff810b9b54>] arch_trigger_all_cpu_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
 [<ffffffff813695ca>] trigger_all_cpu_backtrace include/linux/nmi.h:44 [inline]
 [<ffffffff813695ca>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff813695ca>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff813695ca>] watchdog+0x6fa/0xae0 kernel/hung_task.c:238
 [<ffffffff81190b48>] kthread+0x268/0x300 kernel/kthread.c:211
 [<ffffffff83779d95>] ret_from_fork+0x55/0x80 arch/x86/entry/entry_64.S:510
Code: b3 5f ff f6 c4 10 75 e1 44 89 e8 c1 e0 18 89 04 25 10 b3 5f ff 44 89 fa 09 da 80 cf 04 41 83 ff 02 0f 44 d3 89 14 25 00 b3 5f ff <41> f7 c4 00 02 00 00 74 1a e8 2b 33 17 00 4c 89 e7 57 9d 0f 1f