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BUG: KCSAN: data-race in batadv_tt_local_add / batadv_tt_local_add

read to 0xffff888120c97818 of 2 bytes by task 17456 on cpu 0:
 batadv_tt_local_add+0x11e/0x1200 net/batman-adv/translation-table.c:672
 batadv_interface_tx+0x398/0xbe0 net/batman-adv/soft-interface.c:248
 __netdev_start_xmit include/linux/netdevice.h:4447 [inline]
 netdev_start_xmit include/linux/netdevice.h:4461 [inline]
 xmit_one net/core/dev.c:3420 [inline]
 dev_hard_start_xmit+0xef/0x430 net/core/dev.c:3436
 __dev_queue_xmit+0x14e9/0x1ba0 net/core/dev.c:4013
 dev_queue_xmit+0x21/0x30 net/core/dev.c:4046
 __bpf_tx_skb net/core/filter.c:2060 [inline]
 __bpf_redirect_common net/core/filter.c:2099 [inline]
 __bpf_redirect+0x4b4/0x710 net/core/filter.c:2106
 ____bpf_clone_redirect net/core/filter.c:2139 [inline]
 bpf_clone_redirect+0x1a5/0x1f0 net/core/filter.c:2111
 0xffffffffa000cb84
 bpf_test_run+0x1c3/0x490 net/bpf/test_run.c:44
 bpf_prog_test_run_skb+0x511/0x8a0 net/bpf/test_run.c:362
 bpf_prog_test_run kernel/bpf/syscall.c:2272 [inline]
 __do_sys_bpf+0xf77/0x3150 kernel/bpf/syscall.c:3048
 __se_sys_bpf kernel/bpf/syscall.c:2989 [inline]
 __x64_sys_bpf+0x4c/0x60 kernel/bpf/syscall.c:2989
 do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

write to 0xffff888120c97818 of 2 bytes by task 17457 on cpu 1:
 batadv_tt_local_add+0x21e/0x1200 net/batman-adv/translation-table.c:799
 batadv_interface_tx+0x398/0xbe0 net/batman-adv/soft-interface.c:248
 __netdev_start_xmit include/linux/netdevice.h:4447 [inline]
 netdev_start_xmit include/linux/netdevice.h:4461 [inline]
 xmit_one net/core/dev.c:3420 [inline]
 dev_hard_start_xmit+0xef/0x430 net/core/dev.c:3436
 __dev_queue_xmit+0x14e9/0x1ba0 net/core/dev.c:4013
 dev_queue_xmit+0x21/0x30 net/core/dev.c:4046
 __bpf_tx_skb net/core/filter.c:2060 [inline]
 __bpf_redirect_common net/core/filter.c:2099 [inline]
 __bpf_redirect+0x4b4/0x710 net/core/filter.c:2106
 ____bpf_clone_redirect net/core/filter.c:2139 [inline]
 bpf_clone_redirect+0x1a5/0x1f0 net/core/filter.c:2111
 bpf_prog_bb15b996d00816f9+0xec0/0x1000
 bpf_test_run+0x1c3/0x490 net/bpf/test_run.c:44
 bpf_prog_test_run_skb+0x511/0x8a0 net/bpf/test_run.c:362
 bpf_prog_test_run kernel/bpf/syscall.c:2272 [inline]
 __do_sys_bpf+0xf77/0x3150 kernel/bpf/syscall.c:3048
 __se_sys_bpf kernel/bpf/syscall.c:2989 [inline]
 __x64_sys_bpf+0x4c/0x60 kernel/bpf/syscall.c:2989
 do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 17457 Comm: syz-executor.0 Not tainted 5.5.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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