syzbot

==================================================================
BUG: KCSAN: data-race in ip_tunnel_xmit / ip_tunnel_xmit

read-write to 0xffff88802943a130 of 8 bytes by task 14937 on cpu 1:
 ip_tunnel_xmit+0xb38/0x11b0 net/ipv4/ip_tunnel.c:816
 __gre_xmit net/ipv4/ip_gre.c:466 [inline]
 ipgre_xmit+0x4d9/0x530 net/ipv4/ip_gre.c:648
 __netdev_start_xmit include/linux/netdevice.h:4776 [inline]
 netdev_start_xmit include/linux/netdevice.h:4790 [inline]
 xmit_one+0xf9/0x2e0 net/core/dev.c:3574
 dev_hard_start_xmit net/core/dev.c:3590 [inline]
 __dev_queue_xmit+0xecf/0x1500 net/core/dev.c:4151
 dev_queue_xmit+0x13/0x20 net/core/dev.c:4184
 __bpf_tx_skb net/core/filter.c:2116 [inline]
 __bpf_redirect_no_mac net/core/filter.c:2141 [inline]
 __bpf_redirect+0x544/0x750 net/core/filter.c:2164
 ____bpf_clone_redirect net/core/filter.c:2448 [inline]
 bpf_clone_redirect+0x168/0x1c0 net/core/filter.c:2420
 bpf_prog_eb4214e34d195ba1+0x58/0xa38
 bpf_dispatcher_nop_func include/linux/bpf.h:651 [inline]
 bpf_test_run+0x278/0x440 net/bpf/test_run.c:50
 bpf_prog_test_run_skb+0x6f0/0xe70 net/bpf/test_run.c:581
 bpf_prog_test_run kernel/bpf/syscall.c:3121 [inline]
 __do_sys_bpf+0x3a17/0x99c0 kernel/bpf/syscall.c:4399
 __se_sys_bpf kernel/bpf/syscall.c:4339 [inline]
 __x64_sys_bpf+0x3d/0x50 kernel/bpf/syscall.c:4339
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read-write to 0xffff88802943a130 of 8 bytes by task 14914 on cpu 0:
 ip_tunnel_xmit+0xb38/0x11b0 net/ipv4/ip_tunnel.c:816
 __gre_xmit net/ipv4/ip_gre.c:466 [inline]
 ipgre_xmit+0x4d9/0x530 net/ipv4/ip_gre.c:648
 __netdev_start_xmit include/linux/netdevice.h:4776 [inline]
 netdev_start_xmit include/linux/netdevice.h:4790 [inline]
 xmit_one+0xf9/0x2e0 net/core/dev.c:3574
 dev_hard_start_xmit net/core/dev.c:3590 [inline]
 __dev_queue_xmit+0xecf/0x1500 net/core/dev.c:4151
 dev_queue_xmit+0x13/0x20 net/core/dev.c:4184
 __bpf_tx_skb net/core/filter.c:2116 [inline]
 __bpf_redirect_no_mac net/core/filter.c:2141 [inline]
 __bpf_redirect+0x544/0x750 net/core/filter.c:2164
 ____bpf_clone_redirect net/core/filter.c:2448 [inline]
 bpf_clone_redirect+0x168/0x1c0 net/core/filter.c:2420
 bpf_prog_eb4214e34d195ba1+0x58/0x3f0
 bpf_dispatcher_nop_func include/linux/bpf.h:651 [inline]
 bpf_test_run+0x278/0x440 net/bpf/test_run.c:50
 bpf_prog_test_run_skb+0x6f0/0xe70 net/bpf/test_run.c:581
 bpf_prog_test_run kernel/bpf/syscall.c:3121 [inline]
 __do_sys_bpf+0x3a17/0x99c0 kernel/bpf/syscall.c:4399
 __se_sys_bpf kernel/bpf/syscall.c:4339 [inline]
 __x64_sys_bpf+0x3d/0x50 kernel/bpf/syscall.c:4339
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 14914 Comm: syz-executor.1 Not tainted 5.10.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================