BUG: soft lockup in netlink_sendmsg

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: bfdef05c8da4 Linux 4.14.261
git tree: linux-4.14.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1074f353b00000
kernel config: https://syzkaller.appspot.com/x/.config?x=35edfd9cd1fd16dc
dashboard link: https://syzkaller.appspot.com/bug?extid=c0cfa0e512a4cb67bb5e
compiler: gcc version 10.2.1 20210110 (Debian 10.2.1-6)

Unfortunately, I don't have any reproducer for this issue yet.

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+c0cfa0...@syzkaller.appspotmail.com

watchdog: BUG: soft lockup - CPU#0 stuck for 22s! [syz-executor.2:9463]
Modules linked in:
irq event stamp: 2609424
hardirqs last enabled at (2609423): [<ffffffff87400976>] restore_regs_and_return_to_kernel+0x0/0x2a
hardirqs last disabled at (2609424): [<ffffffff874018ae>] apic_timer_interrupt+0x8e/0xa0 arch/x86/entry/entry_64.S:793
softirqs last enabled at (39428): [<ffffffff8760068b>] __do_softirq+0x68b/0x9ff kernel/softirq.c:314
softirqs last disabled at (37925): [<ffffffff81321d13>] invoke_softirq kernel/softirq.c:368 [inline]
softirqs last disabled at (37925): [<ffffffff81321d13>] irq_exit+0x193/0x240 kernel/softirq.c:409
CPU: 0 PID: 9463 Comm: syz-executor.2 Not tainted 4.14.261-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8880525e6500 task.stack: ffff8880525e8000
RIP: 0010:pv_wait_head_or_lock kernel/locking/qspinlock_paravirt.h:411 [inline]
RIP: 0010:__pv_queued_spin_lock_slowpath+0x265/0x910 kernel/locking/qspinlock.c:465
RSP: 0018:ffff8880525ef7c0 EFLAGS: 00000206 ORIG_RAX: ffffffffffffff10
RAX: 0000000000000003 RBX: ffff8880ba434f00 RCX: fffffbfff11ff408
RDX: 0000000000002aa6 RSI: 0000000000000000 RDI: 0000000000000286
RBP: ffffffff88ffa040 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000
R13: dffffc0000000000 R14: ffffffff88ffa041 R15: ffffed10174869e8
FS: 00007ffbbdf4d700(0000) GS:ffff8880ba400000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000004 CR3: 0000000099e4f000 CR4: 00000000003406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:669 [inline]
queued_spin_lock_slowpath arch/x86/include/asm/qspinlock.h:52 [inline]
queued_spin_lock include/asm-generic/qspinlock.h:90 [inline]
do_raw_spin_lock+0x178/0x200 kernel/locking/spinlock_debug.c:113
spin_lock include/linux/spinlock.h:317 [inline]
find_vmap_area mm/vmalloc.c:771 [inline]
find_vm_area+0x1a/0x1a0 mm/vmalloc.c:1476
__vunmap+0x40/0x300 mm/vmalloc.c:1527
vfree+0x4b/0xd0 mm/vmalloc.c:1612
netlink_skb_destructor+0x17c/0x1c0 net/netlink/af_netlink.c:343
skb_release_head_state+0x11e/0x250 net/core/skbuff.c:625
skb_release_all net/core/skbuff.c:638 [inline]
__kfree_skb net/core/skbuff.c:654 [inline]
consume_skb+0xa7/0x380 net/core/skbuff.c:714
netlink_unicast_kernel net/netlink/af_netlink.c:1295 [inline]
netlink_unicast+0x43f/0x610 net/netlink/af_netlink.c:1320
netlink_sendmsg+0x648/0xbc0 net/netlink/af_netlink.c:1891
sock_sendmsg_nosec net/socket.c:646 [inline]
sock_sendmsg+0xb5/0x100 net/socket.c:656
sock_no_sendpage+0xe2/0x110 net/core/sock.c:2613
kernel_sendpage net/socket.c:3407 [inline]
sock_sendpage+0xdf/0x140 net/socket.c:871
pipe_to_sendpage+0x226/0x2d0 fs/splice.c:451
splice_from_pipe_feed fs/splice.c:502 [inline]
__splice_from_pipe+0x326/0x7a0 fs/splice.c:626
splice_from_pipe fs/splice.c:661 [inline]
generic_splice_sendpage+0xc1/0x110 fs/splice.c:832
do_splice_from fs/splice.c:851 [inline]
do_splice fs/splice.c:1147 [inline]
SYSC_splice fs/splice.c:1402 [inline]
SyS_splice+0xd59/0x1380 fs/splice.c:1382
do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x7ffbbf5f8e99
RSP: 002b:00007ffbbdf4d168 EFLAGS: 00000246 ORIG_RAX: 0000000000000113
RAX: ffffffffffffffda RBX: 00007ffbbf70c030 RCX: 00007ffbbf5f8e99
RDX: 0000000000000005 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 00007ffbbf652ff1 R08: 000000000004ffe6 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffed8a5acef R14: 00007ffbbdf4d300 R15: 0000000000022000
Code: 84 c0 0f 85 2e 04 00 00 48 89 e9 48 89 ee c6 45 01 01 ba 00 80 00 00 48 c1 e9 03 83 e6 07 41 b8 01 00 00 00 4c 01 e9 eb 0b f3 90 <83> ea 01 0f 84 42 04 00 00 0f b6 01 40 38 f0 7f 08 84 c0 0f 85
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 9465 Comm: syz-executor.5 Not tainted 4.14.261-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff88805261a580 task.stack: ffff888052620000
RIP: 0010:rcu_read_unlock_sched_notrace include/linux/rcupdate.h:775 [inline]
RIP: 0010:trace_netif_rx include/trace/events/net.h:134 [inline]
RIP: 0010:netif_rx_internal+0x3e0/0x800 net/core/dev.c:4032
RSP: 0018:ffff8880ba5075a8 EFLAGS: 00000202
RAX: 0000000000000001 RBX: 0000000000000001 RCX: 0000000000000000
RDX: dffffc0000000000 RSI: 00000000ffffffff RDI: 0000000000000286
RBP: ffff8880a21e1640 R08: 0000000000000000 R09: 0000000000000008
R10: 0000000000000000 R11: ffff88805261a580 R12: 1ffff110174a0eb6
R13: ffff8880a11bcc00 R14: ffff8880a0d88c90 R15: ffffffff87f0c280
FS: 00007efcc210c700(0000) GS:ffff8880ba500000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000000 CR3: 00000000b08d9000 CR4: 00000000003406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<IRQ>
dev_forward_skb+0x39/0x50 net/core/dev.c:1866
veth_xmit+0xf1/0x300 drivers/net/veth.c:114
__netdev_start_xmit include/linux/netdevice.h:4051 [inline]
netdev_start_xmit include/linux/netdevice.h:4060 [inline]
xmit_one net/core/dev.c:3005 [inline]
dev_hard_start_xmit+0x188/0x890 net/core/dev.c:3021
__dev_queue_xmit+0x1d7f/0x2480 net/core/dev.c:3521
neigh_resolve_output+0x4e5/0x870 net/core/neighbour.c:1369
neigh_output include/net/neighbour.h:500 [inline]
ip6_finish_output2+0xf48/0x1f10 net/ipv6/ip6_output.c:120
ip6_finish_output+0x5c6/0xd50 net/ipv6/ip6_output.c:192
NF_HOOK_COND include/linux/netfilter.h:239 [inline]
ip6_output+0x1c5/0x660 net/ipv6/ip6_output.c:209
dst_output include/net/dst.h:470 [inline]
NF_HOOK include/linux/netfilter.h:250 [inline]
ndisc_send_skb+0x82a/0x1390 net/ipv6/ndisc.c:483
ndisc_send_rs+0x125/0x630 net/ipv6/ndisc.c:677
addrconf_rs_timer+0x2bb/0x5a0 net/ipv6/addrconf.c:3769
call_timer_fn+0x14a/0x650 kernel/time/timer.c:1280
expire_timers+0x232/0x4d0 kernel/time/timer.c:1319
__run_timers kernel/time/timer.c:1637 [inline]
run_timer_softirq+0x1d5/0x5a0 kernel/time/timer.c:1650
__do_softirq+0x24d/0x9ff kernel/softirq.c:288
invoke_softirq kernel/softirq.c:368 [inline]
irq_exit+0x193/0x240 kernel/softirq.c:409
exiting_irq arch/x86/include/asm/apic.h:638 [inline]
smp_apic_timer_interrupt+0x141/0x5e0 arch/x86/kernel/apic/apic.c:1106
apic_timer_interrupt+0x93/0xa0 arch/x86/entry/entry_64.S:793
</IRQ>
RIP: 0010:_raw_spin_unlock_irqrestore+0x71/0xe0 kernel/locking/spinlock.c:193
RSP: 0018:ffff8880526277d8 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff10
RAX: 0000000080000001 RBX: 0000000000000286 RCX: 0000000000000000
RDX: 0000000000000004 RSI: ffff88805261ae58 RDI: 0000000000000001
RBP: ffffffff8bfc8c48 R08: ffffffff8b9a8ba0 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000286
R13: ffff88809abf4e70 R14: ffffffff8bfc8c48 R15: 0000000000000000
__debug_object_init+0x3fc/0x7a0 lib/debugobjects.c:380
debug_object_init lib/debugobjects.c:393 [inline]
debug_object_activate+0x391/0x490 lib/debugobjects.c:474
debug_rcu_head_queue kernel/rcu/rcu.h:152 [inline]
__call_rcu.constprop.0+0x31/0x7d0 kernel/rcu/tree.c:3050
__purge_vmap_area_lazy+0x162/0x250 mm/vmalloc.c:707
vm_unmap_aliases mm/vmalloc.c:1126 [inline]
vm_unmap_aliases+0x390/0x460 mm/vmalloc.c:1089
change_page_attr_set_clr+0x5c3/0xa30 arch/x86/mm/pageattr.c:1472
change_page_attr_clear arch/x86/mm/pageattr.c:1532 [inline]
set_memory_ro+0x68/0x80 arch/x86/mm/pageattr.c:1761
bpf_prog_lock_ro include/linux/filter.h:612 [inline]
bpf_prog_select_runtime+0x143/0x4e0 kernel/bpf/core.c:1464
bpf_migrate_filter+0x242/0x2d0 net/core/filter.c:1060
bpf_prepare_filter+0x14c/0x320 net/core/filter.c:1108
__get_filter+0x196/0x240 net/core/filter.c:1301
sk_attach_filter+0x1b/0x140 net/core/filter.c:1316
sock_setsockopt+0x119a/0x1a50 net/core/sock.c:927
SYSC_setsockopt net/socket.c:1861 [inline]
SyS_setsockopt+0x1a4/0x1e0 net/socket.c:1844
do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x7efcc3796e99
RSP: 002b:00007efcc210c168 EFLAGS: 00000246 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 00007efcc38a9f60 RCX: 00007efcc3796e99
RDX: 000000000000001a RSI: 0000000000000001 RDI: 0000000000000005
RBP: 00007efcc37f0ff1 R08: 0000000000000010 R09: 0000000000000000
R10: 000000002002eff0 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffe8ee1ff0f R14: 00007efcc210c300 R15: 0000000000022000
Code: 3c 10 00 0f 85 e8 03 00 00 48 8b 05 53 a3 30 04 e8 66 a0 81 fb 85 c0 74 12 e8 cd be 90 fb 80 3d ea a4 2e 04 00 0f 84 ef 02 00 00 <e8> bb be 90 fb 65 ff 0d d4 02 3e 7a 0f 85 b4 fc ff ff e8 a9 be
----------------
Code disassembly (best guess):
0: 84 c0 test %al,%al
2: 0f 85 2e 04 00 00 jne 0x436
8: 48 89 e9 mov %rbp,%rcx
b: 48 89 ee mov %rbp,%rsi
e: c6 45 01 01 movb $0x1,0x1(%rbp)
12: ba 00 80 00 00 mov $0x8000,%edx
17: 48 c1 e9 03 shr $0x3,%rcx
1b: 83 e6 07 and $0x7,%esi
1e: 41 b8 01 00 00 00 mov $0x1,%r8d
24: 4c 01 e9 add %r13,%rcx
27: eb 0b jmp 0x34
29: f3 90 pause
* 2b: 83 ea 01 sub $0x1,%edx <-- trapping instruction
2e: 0f 84 42 04 00 00 je 0x476
34: 0f b6 01 movzbl (%rcx),%eax
37: 40 38 f0 cmp %sil,%al
3a: 7f 08 jg 0x44
3c: 84 c0 test %al,%al
3e: 0f .byte 0xf
3f: 85 .byte 0x85


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.