BUG: soft lockup in tipc_disc_timeout

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: b172b44fcb17 Linux 4.19.206
git tree: linux-4.19.y
console output: https://syzkaller.appspot.com/x/log.txt?x=12f998f7300000
kernel config: https://syzkaller.appspot.com/x/.config?x=b9ba3521ce0be3cd
dashboard link: https://syzkaller.appspot.com/bug?extid=6388f6facdb859d5b763
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+6388f6...@syzkaller.appspotmail.com

audit: type=1800 audit(1631992595.022:553): pid=6587 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="syz-executor.5" name="bus" dev="sda1" ino=14411 res=0
IPv6: ADDRCONF(NETDEV_UP): vlan527: link is not ready
netlink: 24 bytes leftover after parsing attributes in process `syz-executor.4'.
watchdog: BUG: soft lockup - CPU#1 stuck for 23s! [syz-executor.0:6500]
Modules linked in:
irq event stamp: 3769437
hardirqs last enabled at (3769436): [<ffffffff81003ce4>] trace_hardirqs_on_thunk+0x1a/0x1c
hardirqs last disabled at (3769437): [<ffffffff81003d00>] trace_hardirqs_off_thunk+0x1a/0x1c
softirqs last enabled at (17538): [<ffffffff88400678>] __do_softirq+0x678/0x980 kernel/softirq.c:318
softirqs last disabled at (17541): [<ffffffff81393705>] invoke_softirq kernel/softirq.c:372 [inline]
softirqs last disabled at (17541): [<ffffffff81393705>] irq_exit+0x215/0x260 kernel/softirq.c:412
CPU: 1 PID: 6500 Comm: syz-executor.0 Not tainted 4.19.206-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:__sanitizer_cov_trace_cmp4+0x0/0x20 kernel/kcov.c:162
Code: b6 d6 40 0f b6 f7 31 ff eb 80 48 8b 0c 24 0f b7 d6 0f b7 f7 bf 02 00 00 00 e9 6c ff ff ff 66 66 2e 0f 1f 84 00 00 00 00 00 90 <48> 8b 0c 24 89 f2 89 fe bf 04 00 00 00 e9 4e ff ff ff 66 66 2e 0f
RSP: 0018:ffff8880ba1075f8 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: 000000000000003f RBX: ffff8880ba107738 RCX: ffffffff8703dc7f
RDX: 0000000000000100 RSI: 0000000000000060 RDI: 0000000000000000
RBP: 0000000000000009 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000006 R11: ffffffff87023760 R12: 0000000000000009
R13: 0000000000000060 R14: fc01000000000000 R15: 0000000000000000
FS: 00007fc613a69700(0000) GS:ffff8880ba100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1f94041718 CR3: 0000000009e6d000 CR4: 00000000001426e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<IRQ>
ipv6_get_saddr_eval+0xd85/0x1020 net/ipv6/addrconf.c:1575
__ipv6_dev_get_saddr+0x20b/0x5f0 net/ipv6/addrconf.c:1639
ipv6_dev_get_saddr+0x56c/0xc20 net/ipv6/addrconf.c:1774
ip6_route_get_saddr include/net/ip6_route.h:124 [inline]
ip6_dst_lookup_tail+0x1233/0x19b0 net/ipv6/ip6_output.c:997
ip6_dst_lookup_flow+0x8c/0x1d0 net/ipv6/ip6_output.c:1120
tipc_udp_xmit+0x2c4/0xc10 net/tipc/udp_media.c:192
tipc_udp_send_msg+0x279/0x490 net/tipc/udp_media.c:248
tipc_bearer_xmit_skb+0x15b/0x330 net/tipc/bearer.c:518
tipc_disc_timeout+0x855/0xc90 net/tipc/discover.c:332
call_timer_fn+0x177/0x700 kernel/time/timer.c:1338
expire_timers+0x243/0x4e0 kernel/time/timer.c:1375
__run_timers kernel/time/timer.c:1696 [inline]
run_timer_softirq+0x21c/0x670 kernel/time/timer.c:1709
__do_softirq+0x265/0x980 kernel/softirq.c:292
invoke_softirq kernel/softirq.c:372 [inline]
irq_exit+0x215/0x260 kernel/softirq.c:412
exiting_irq arch/x86/include/asm/apic.h:536 [inline]
smp_apic_timer_interrupt+0x136/0x550 arch/x86/kernel/apic/apic.c:1098
apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:894
</IRQ>
RIP: 0010:__sanitizer_cov_trace_pc+0x0/0x50 kernel/kcov.c:97
Code: ff 48 89 df e8 11 d3 35 00 e9 ab fe ff ff 4c 89 ef e8 04 d3 35 00 e9 23 fe ff ff 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <48> 8b 34 24 65 48 8b 04 25 c0 df 01 00 65 8b 15 7c 4c 9f 7e 81 e2
RSP: 0018:ffff88801423f768 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff818ba2ae
RDX: 0000000000000000 RSI: ffff888098b46140 RDI: 0000000000000001
RBP: ffffea00027861c8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000
R13: ffffea00027861c0 R14: dffffc0000000000 R15: 00007fc61435d000
__read_once_size include/linux/compiler.h:261 [inline]
compound_head include/linux/page-flags.h:142 [inline]
PageSwapBacked include/linux/page-flags.h:295 [inline]
mm_counter_file include/linux/mm.h:1642 [inline]
mm_counter include/linux/mm.h:1651 [inline]
zap_pte_range mm/memory.c:1349 [inline]
zap_pmd_range mm/memory.c:1463 [inline]
zap_pud_range mm/memory.c:1492 [inline]
zap_p4d_range mm/memory.c:1513 [inline]
unmap_page_range+0x136b/0x2c50 mm/memory.c:1534
unmap_single_vma+0x198/0x300 mm/memory.c:1579
unmap_vmas+0xa9/0x180 mm/memory.c:1609
exit_mmap+0x2b9/0x530 mm/mmap.c:3093
__mmput kernel/fork.c:1015 [inline]
mmput+0x14e/0x4a0 kernel/fork.c:1036
exit_mm kernel/exit.c:549 [inline]
do_exit+0xaec/0x2be0 kernel/exit.c:857
do_group_exit+0x125/0x310 kernel/exit.c:967
get_signal+0x3f2/0x1f70 kernel/signal.c:2589
do_signal+0x8f/0x1670 arch/x86/kernel/signal.c:799
exit_to_usermode_loop+0x204/0x2a0 arch/x86/entry/common.c:163
prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline]
syscall_return_slowpath arch/x86/entry/common.c:271 [inline]
do_syscall_64+0x538/0x620 arch/x86/entry/common.c:296
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7fc6164f2739
Code: Bad RIP value.
RSP: 002b:00007fc613a69188 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: 0000000000000012 RBX: 00007fc6165f6f80 RCX: 00007fc6164f2739
RDX: 0000000000000012 RSI: 0000000020000140 RDI: 0000000000000004
RBP: 00007fc61654ccc4 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fc6165f6f80
R13: 00007ffd8bb5d05f R14: 00007fc613a69300 R15: 0000000000022000
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0 skipped: idling at native_safe_halt+0xe/0x10 arch/x86/include/asm/irqflags.h:60
----------------
Code disassembly (best guess):
0: b6 d6 mov $0xd6,%dh
2: 40 0f b6 f7 movzbl %dil,%esi
6: 31 ff xor %edi,%edi
8: eb 80 jmp 0xffffff8a
a: 48 8b 0c 24 mov (%rsp),%rcx
e: 0f b7 d6 movzwl %si,%edx
11: 0f b7 f7 movzwl %di,%esi
14: bf 02 00 00 00 mov $0x2,%edi
19: e9 6c ff ff ff jmpq 0xffffff8a
1e: 66 66 2e 0f 1f 84 00 data16 nopw %cs:0x0(%rax,%rax,1)
25: 00 00 00 00
29: 90 nop
* 2a: 48 8b 0c 24 mov (%rsp),%rcx <-- trapping instruction
2e: 89 f2 mov %esi,%edx
30: 89 fe mov %edi,%esi
32: bf 04 00 00 00 mov $0x4,%edi
37: e9 4e ff ff ff jmpq 0xffffff8a
3c: 66 data16
3d: 66 data16
3e: 2e cs
3f: 0f .byte 0xf


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[syzbot]

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