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BUG: KCSAN: data-race in iptunnel_xmit / iptunnel_xmit

read-write to 0xffff8881334ad168 of 8 bytes by task 18138 on cpu 0:
 iptunnel_xmit_stats include/net/ip_tunnels.h:470 [inline]
 iptunnel_xmit+0x42b/0x490 net/ipv4/ip_tunnel_core.c:87
 ip_tunnel_xmit+0xf2f/0x11c0 net/ipv4/ip_tunnel.c:811
 __gre_xmit net/ipv4/ip_gre.c:469 [inline]
 ipgre_xmit+0x525/0x570 net/ipv4/ip_gre.c:657
 __netdev_start_xmit include/linux/netdevice.h:4805 [inline]
 netdev_start_xmit include/linux/netdevice.h:4819 [inline]
 xmit_one+0xc0/0x2a0 net/core/dev.c:3588
 dev_hard_start_xmit+0x72/0x120 net/core/dev.c:3604
 __dev_queue_xmit+0x84c/0xfe0 net/core/dev.c:4253
 dev_queue_xmit include/linux/netdevice.h:2994 [inline]
 __bpf_tx_skb net/core/filter.c:2114 [inline]
 __bpf_redirect_no_mac net/core/filter.c:2139 [inline]
 __bpf_redirect+0x556/0x840 net/core/filter.c:2162
 ____bpf_clone_redirect net/core/filter.c:2429 [inline]
 bpf_clone_redirect+0x168/0x1c0 net/core/filter.c:2401
 ___bpf_prog_run+0x278/0x2da0 kernel/bpf/core.c:1850
 __bpf_prog_run512+0x70/0xa0 kernel/bpf/core.c:2075
 bpf_dispatcher_nop_func include/linux/bpf.h:869 [inline]
 __bpf_prog_run include/linux/filter.h:628 [inline]
 bpf_prog_run include/linux/filter.h:635 [inline]
 bpf_test_run+0x1eb/0x410 net/bpf/test_run.c:402
 bpf_prog_test_run_skb+0x76b/0x9f0 net/bpf/test_run.c:1155
 bpf_prog_test_run+0x22a/0x250 kernel/bpf/syscall.c:3591
 __sys_bpf+0x3c4/0x630 kernel/bpf/syscall.c:4935
 __do_sys_bpf kernel/bpf/syscall.c:5021 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:5019 [inline]
 __x64_sys_bpf+0x3f/0x50 kernel/bpf/syscall.c:5019
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x46/0xb0

read-write to 0xffff8881334ad168 of 8 bytes by task 18148 on cpu 1:
 iptunnel_xmit_stats include/net/ip_tunnels.h:470 [inline]
 iptunnel_xmit+0x42b/0x490 net/ipv4/ip_tunnel_core.c:87
 ip_tunnel_xmit+0xf2f/0x11c0 net/ipv4/ip_tunnel.c:811
 __gre_xmit net/ipv4/ip_gre.c:469 [inline]
 ipgre_xmit+0x525/0x570 net/ipv4/ip_gre.c:657
 __netdev_start_xmit include/linux/netdevice.h:4805 [inline]
 netdev_start_xmit include/linux/netdevice.h:4819 [inline]
 xmit_one+0xc0/0x2a0 net/core/dev.c:3588
 dev_hard_start_xmit+0x72/0x120 net/core/dev.c:3604
 __dev_queue_xmit+0x84c/0xfe0 net/core/dev.c:4253
 dev_queue_xmit include/linux/netdevice.h:2994 [inline]
 __bpf_tx_skb net/core/filter.c:2114 [inline]
 __bpf_redirect_no_mac net/core/filter.c:2139 [inline]
 __bpf_redirect+0x556/0x840 net/core/filter.c:2162
 ____bpf_clone_redirect net/core/filter.c:2429 [inline]
 bpf_clone_redirect+0x168/0x1c0 net/core/filter.c:2401
 ___bpf_prog_run+0x278/0x2da0 kernel/bpf/core.c:1850
 __bpf_prog_run512+0x70/0xa0 kernel/bpf/core.c:2075
 bpf_dispatcher_nop_func include/linux/bpf.h:869 [inline]
 __bpf_prog_run include/linux/filter.h:628 [inline]
 bpf_prog_run include/linux/filter.h:635 [inline]
 bpf_test_run+0x1eb/0x410 net/bpf/test_run.c:402
 bpf_prog_test_run_skb+0x76b/0x9f0 net/bpf/test_run.c:1155
 bpf_prog_test_run+0x22a/0x250 kernel/bpf/syscall.c:3591
 __sys_bpf+0x3c4/0x630 kernel/bpf/syscall.c:4935
 __do_sys_bpf kernel/bpf/syscall.c:5021 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:5019 [inline]
 __x64_sys_bpf+0x3f/0x50 kernel/bpf/syscall.c:5019
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x46/0xb0

value changed: 0x0000000000000511 -> 0x0000000000000512

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 18148 Comm: syz-executor.2 Not tainted 5.18.0-syzkaller-13818-gd0e60d46bc03-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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