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BUG: KASAN: null-ptr-deref in atomic_read include/asm-generic/atomic-instrumented.h:21 [inline]
BUG: KASAN: null-ptr-deref in refcount_sub_and_test_checked+0x9d/0x310 lib/refcount.c:179
net_ratelimit: 13 callbacks suppressed
TCP: request_sock_TCPv6: Possible SYN flooding on port 20002. Sending cookies.  Check SNMP counters.
Read of size 4 at addr 000000000000002e by task blkid/30329

CPU: 0 PID: 30329 Comm: blkid Not tainted 4.19.0-rc6+ #245
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1c4/0x2b4 lib/dump_stack.c:113
 kasan_report_error mm/kasan/report.c:352 [inline]
 kasan_report.cold.9+0x6d/0x309 mm/kasan/report.c:412
 check_memory_region_inline mm/kasan/kasan.c:260 [inline]
 check_memory_region+0x13e/0x1b0 mm/kasan/kasan.c:267
 kasan_check_read+0x11/0x20 mm/kasan/kasan.c:272
 atomic_read include/asm-generic/atomic-instrumented.h:21 [inline]
 refcount_sub_and_test_checked+0x9d/0x310 lib/refcount.c:179
TCP: request_sock_TCPv6: Possible SYN flooding on port 20002. Sending cookies.  Check SNMP counters.
 refcount_dec_and_test_checked+0x1a/0x20 lib/refcount.c:212
 ip_fib_metrics_put include/net/ip.h:428 [inline]
 fib6_info_destroy_rcu+0x2ef/0x3e0 net/ipv6/ip6_fib.c:204
 __rcu_reclaim kernel/rcu/rcu.h:236 [inline]
 rcu_do_batch kernel/rcu/tree.c:2576 [inline]
 invoke_rcu_callbacks kernel/rcu/tree.c:2880 [inline]
 __rcu_process_callbacks kernel/rcu/tree.c:2847 [inline]
 rcu_process_callbacks+0xf23/0x2670 kernel/rcu/tree.c:2864
 __do_softirq+0x30b/0xad8 kernel/softirq.c:292
 invoke_softirq kernel/softirq.c:372 [inline]
 irq_exit+0x17f/0x1c0 kernel/softirq.c:412
 exiting_irq arch/x86/include/asm/apic.h:536 [inline]
 smp_apic_timer_interrupt+0x1cb/0x760 arch/x86/kernel/apic/apic.c:1056
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:864
 </IRQ>
RIP: 0010:__sanitizer_cov_trace_const_cmp8+0x13/0x20 kernel/kcov.c:195
Code: 00 48 89 e5 48 8b 4d 08 e8 6a fe ff ff 5d c3 0f 1f 84 00 00 00 00 00 55 48 89 f2 48 89 fe bf 07 00 00 00 48 89 e5 48 8b 4d 08 <e8> 48 fe ff ff 5d c3 66 0f 1f 44 00 00 55 48 89 e5 41 57 41 56 41
RSP: 0018:ffff8801c3916d18 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: dffffc0000000000 RBX: ffffea0006ce4c00 RCX: ffffffff81b72863
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000007
RBP: ffff8801c3916d18 R08: ffff8801968e2140 R09: fffff94000d9c986
R10: fffff94000d9c986 R11: ffffea0006ce4c33 R12: 0000000000000000
R13: ffff8801c3917070 R14: ffffea0006ce4c08 R15: ffffea0006b6ba08
TCP: request_sock_TCPv6: Possible SYN flooding on port 20002. Sending cookies.  Check SNMP counters.
 PageCompound include/linux/page-flags.h:156 [inline]
 PageTransCompound include/linux/page-flags.h:564 [inline]
 page_remove_rmap+0x453/0x1a30 mm/rmap.c:1319
 zap_pte_range mm/memory.c:1338 [inline]
 zap_pmd_range mm/memory.c:1440 [inline]
 zap_pud_range mm/memory.c:1469 [inline]
 zap_p4d_range mm/memory.c:1490 [inline]
 unmap_page_range+0xf14/0x2030 mm/memory.c:1511
TCP: request_sock_TCPv6: Possible SYN flooding on port 20002. Sending cookies.  Check SNMP counters.
 unmap_single_vma+0x19b/0x310 mm/memory.c:1556
 unmap_vmas+0x125/0x200 mm/memory.c:1586
 exit_mmap+0x2be/0x590 mm/mmap.c:3093
 __mmput kernel/fork.c:1001 [inline]
 mmput+0x247/0x610 kernel/fork.c:1022
 exit_mm kernel/exit.c:545 [inline]
 do_exit+0xe6f/0x2610 kernel/exit.c:854
 do_group_exit+0x177/0x440 kernel/exit.c:970
 __do_sys_exit_group kernel/exit.c:981 [inline]
 __se_sys_exit_group kernel/exit.c:979 [inline]
 __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:979
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7f1f3684a1e8
Code: Bad RIP value.
RSP: 002b:00007ffed7b0a3d8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007f1f3684a1e8
RDX: 0000000000000002 RSI: 000000000000003c RDI: 0000000000000002
RBP: 00007f1f36b1f840 R08: 00000000000000e7 R09: ffffffffffffffa8
R10: 00007f1f36b25740 R11: 0000000000000246 R12: 00007f1f36b1f840
R13: 0000000000000001 R14: 0000000000000000 R15: 0000000000000000
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