syzbot

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BUG: KCSAN: data-race in can_receive / can_stat_update

write to 0xffff88801cc5aa08 of 8 bytes by interrupt on cpu 1:
 can_receive+0x59/0x220 net/can/af_can.c:651
 can_rcv+0x9e/0x170 net/can/af_can.c:696
 __netif_receive_skb_one_core net/core/dev.c:5384 [inline]
 __netif_receive_skb+0x8b/0x1b0 net/core/dev.c:5498
 process_backlog+0x23f/0x3e0 net/core/dev.c:6365
 __napi_poll+0x65/0x3e0 net/core/dev.c:6912
 napi_poll net/core/dev.c:6979 [inline]
 net_rx_action+0x29f/0x680 net/core/dev.c:7065
 __do_softirq+0x13c/0x2c3 kernel/softirq.c:345
 run_ksoftirqd+0x13/0x20 kernel/softirq.c:652
 smpboot_thread_fn+0x34f/0x520 kernel/smpboot.c:165
 kthread+0x20b/0x230 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294

read to 0xffff88801cc5aa08 of 8 bytes by interrupt on cpu 0:
 can_stat_update+0x363/0x700 net/can/proc.c:146
 call_timer_fn+0x2e/0x240 kernel/time/timer.c:1431
 expire_timers+0x116/0x260 kernel/time/timer.c:1476
 __run_timers+0x358/0x3f0 kernel/time/timer.c:1745
 run_timer_softirq+0x19/0x30 kernel/time/timer.c:1758
 __do_softirq+0x13c/0x2c3 kernel/softirq.c:345
 invoke_softirq kernel/softirq.c:221 [inline]
 __irq_exit_rcu+0xb4/0xc0 kernel/softirq.c:422
 sysvec_apic_timer_interrupt+0x6e/0x80 arch/x86/kernel/apic/apic.c:1100
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:632
 smap_restore arch/x86/include/asm/smap.h:70 [inline]
 kcsan_setup_watchpoint+0x436/0x470 kernel/kcsan/core.c:590
 inet_twsk_purge+0x3e9/0x410 net/ipv4/inet_timewait_sock.c:264
 dccp_v4_exit_batch+0x16/0x20 net/dccp/ipv4.c:1022
 ops_exit_list net/core/net_namespace.c:178 [inline]
 cleanup_net+0x4dc/0x900 net/core/net_namespace.c:595
 process_one_work+0x3e1/0x950 kernel/workqueue.c:2275
 worker_thread+0x616/0xa70 kernel/workqueue.c:2421
 kthread+0x20b/0x230 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 10069 Comm: kworker/u4:5 Not tainted 5.12.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: netns cleanup_net
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