==================================================================
BUG: KCSAN: data-race in __perf_event_overflow / fasync_remove_entry

write to 0xffff88811fdd7700 of 8 bytes by task 3933 on cpu 0:
 fasync_remove_entry+0xb7/0x120 fs/fcntl.c:882
 fasync_helper+0xc9/0xd6 fs/fcntl.c:981
 perf_fasync+0x64/0x90 kernel/events/core.c:6011
 __fput+0x448/0x4f0 fs/file_table.c:277
 ____fput+0x1b/0x30 fs/file_table.c:313
 task_work_run+0xf5/0x130 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_usermode_loop+0x2ae/0x2c0 arch/x86/entry/common.c:164
 prepare_exit_to_usermode arch/x86/entry/common.c:195 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:278 [inline]
 do_syscall_64+0x36e/0x390 arch/x86/entry/common.c:304
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88811fdd7700 of 8 bytes by interrupt on cpu 1:
 __perf_event_overflow+0x116/0x200 kernel/events/core.c:8438
 perf_swevent_hrtimer+0x261/0x280 kernel/events/core.c:9822
 __run_hrtimer kernel/time/hrtimer.c:1517 [inline]
 __hrtimer_run_queues+0x271/0x600 kernel/time/hrtimer.c:1579
 hrtimer_interrupt+0x226/0x490 kernel/time/hrtimer.c:1641
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1119 [inline]
 smp_apic_timer_interrupt+0xd8/0x270 arch/x86/kernel/apic/apic.c:1144
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829
 xfrm_lookup_with_ifid+0x265/0x1550 net/xfrm/xfrm_policy.c:3082
 xfrm_lookup+0x3d/0x60 net/xfrm/xfrm_policy.c:3177
 icmp6_dst_alloc+0x27a/0x3c0 net/ipv6/route.c:3160
 mld_sendpack+0x306/0x540 net/ipv6/mcast.c:1671
 mld_send_cr net/ipv6/mcast.c:1978 [inline]
 mld_ifc_timer_expire+0x310/0x620 net/ipv6/mcast.c:2477
 call_timer_fn+0x58/0x2e0 kernel/time/timer.c:1405
 expire_timers kernel/time/timer.c:1450 [inline]
 __run_timers kernel/time/timer.c:1774 [inline]
 __run_timers kernel/time/timer.c:1741 [inline]
 run_timer_softirq+0xb14/0xbd0 kernel/time/timer.c:1787
 __do_softirq+0x118/0x34a kernel/softirq.c:292
 invoke_softirq kernel/softirq.c:373 [inline]
 irq_exit+0xb5/0xd0 kernel/softirq.c:413
 exiting_irq arch/x86/include/asm/apic.h:546 [inline]
 smp_apic_timer_interrupt+0xe2/0x270 arch/x86/kernel/apic/apic.c:1146
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829
 batadv_hardif_get_by_netdev+0x6b/0x1d0 net/batman-adv/hard-interface.c:71
 batadv_hard_if_event+0xaf/0xa10 net/batman-adv/hard-interface.c:1031
 notifier_call_chain+0xda/0x160 kernel/notifier.c:83
 __raw_notifier_call_chain kernel/notifier.c:361 [inline]
 raw_notifier_call_chain+0x33/0x50 kernel/notifier.c:368
 call_netdevice_notifiers_info net/core/dev.c:1943 [inline]
 call_netdevice_notifiers_info+0x96/0x110 net/core/dev.c:1928
 netdev_state_change net/core/dev.c:1378 [inline]
 netdev_state_change+0xb2/0xd0 net/core/dev.c:1371
 do_setlink+0xdc0/0x1ec0 net/core/rtnetlink.c:2814
 rtnl_group_changelink net/core/rtnetlink.c:3103 [inline]
 __rtnl_newlink+0xa03/0xfb0 net/core/rtnetlink.c:3257
 rtnl_newlink+0x5f/0x90 net/core/rtnetlink.c:3377
 rtnetlink_rcv_msg+0x1d0/0x4e0 net/core/rtnetlink.c:5438
 netlink_rcv_skb+0xaf/0x260 net/netlink/af_netlink.c:2477
 rtnetlink_rcv+0x22/0x30 net/core/rtnetlink.c:5456
 netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline]
 netlink_unicast+0x390/0x4c0 net/netlink/af_netlink.c:1328
 netlink_sendmsg+0x4cf/0x8a0 net/netlink/af_netlink.c:1917
 sock_sendmsg_nosec net/socket.c:652 [inline]
 sock_sendmsg+0x98/0xc0 net/socket.c:672
 ____sys_sendmsg+0x493/0x4c0 net/socket.c:2343
 ___sys_sendmsg+0xb5/0x100 net/socket.c:2397
 __sys_sendmsg+0x9b/0x150 net/socket.c:2430
 __do_sys_sendmsg net/socket.c:2439 [inline]
 __se_sys_sendmsg net/socket.c:2437 [inline]
 __x64_sys_sendmsg+0x4c/0x60 net/socket.c:2437
 do_syscall_64+0xc7/0x390 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 3938 Comm: syz-executor.4 Not tainted 5.6.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================