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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
Read of size 4 at addr 000000000000002e by task kworker/1:4/7608

CPU: 1 PID: 7608 Comm: kworker/1:4 Not tainted 4.19.0-rc6+ #245
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: rcu_gp process_srcu
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
 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:rdtsc arch/x86/include/asm/msr.h:205 [inline]
RIP: 0010:rdtsc_ordered arch/x86/include/asm/msr.h:232 [inline]
RIP: 0010:delay_tsc+0x4c/0xc0 arch/x86/lib/delay.c:61
Code: e8 0f 31 48 c1 e2 20 48 09 c2 49 89 d4 eb 16 f3 90 bf 01 00 00 00 e8 83 71 a6 f9 e8 6e 1a de fb 44 39 f0 75 36 0f ae e8 0f 31 <48> c1 e2 20 48 89 d3 48 09 c3 48 89 d8 4c 29 e0 4c 39 e8 73 24 bf
RSP: 0018:ffff88019c3b7128 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: 00000000eba62256 RBX: 000000cfeba621c1 RCX: ffffffff838d1a1a
RDX: 00000000000000cf RSI: ffffffff838d1a28 RDI: 0000000000000005
RBP: ffff88019c3b7148 R08: ffff88019c096580 R09: 1ffffd1ffffa0a80
R10: ffff88019c3b7250 R11: ffffffff8af02f67 R12: 000000cfeba607b9
R13: 0000000000002ced R14: 0000000000000001 R15: ffffffff8af02bc0
 __delay arch/x86/lib/delay.c:161 [inline]
 __const_udelay+0x62/0x80 arch/x86/lib/delay.c:175
 try_check_zero+0x384/0x5f0 kernel/rcu/srcutree.c:721
 srcu_advance_state kernel/rcu/srcutree.c:1155 [inline]
 process_srcu+0x6bf/0x1460 kernel/rcu/srcutree.c:1249
 process_one_work+0xc90/0x1b90 kernel/workqueue.c:2153
 worker_thread+0x17f/0x1390 kernel/workqueue.c:2296
 kthread+0x35a/0x420 kernel/kthread.c:246
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:413
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