syzbot

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BUG: KCSAN: data-race in iptunnel_xmit / iptunnel_xmit

read-write to 0xffff888122fb7168 of 8 bytes by task 10543 on cpu 1:
 iptunnel_xmit_stats include/net/ip_tunnels.h:483 [inline]
 iptunnel_xmit+0x405/0x470 net/ipv4/ip_tunnel_core.c:87
 ip_tunnel_xmit+0x1631/0x16f0 net/ipv4/ip_tunnel.c:813
 __gre_xmit net/ipv4/ip_gre.c:469 [inline]
 ipgre_xmit+0x51b/0x580 net/ipv4/ip_gre.c:661
 __netdev_start_xmit include/linux/netdevice.h:4840 [inline]
 netdev_start_xmit include/linux/netdevice.h:4854 [inline]
 xmit_one+0xc0/0x2a0 net/core/dev.c:3590
 dev_hard_start_xmit+0x72/0x120 net/core/dev.c:3606
 __dev_queue_xmit+0x84c/0xfe0 net/core/dev.c:4256
 dev_queue_xmit include/linux/netdevice.h:3008 [inline]
 __bpf_tx_skb net/core/filter.c:2116 [inline]
 __bpf_redirect_no_mac net/core/filter.c:2141 [inline]
 __bpf_redirect+0x55a/0x820 net/core/filter.c:2164
 ____bpf_clone_redirect net/core/filter.c:2431 [inline]
 bpf_clone_redirect+0x168/0x1c0 net/core/filter.c:2403
 ___bpf_prog_run+0x278/0x2da0 kernel/bpf/core.c:1818
 __bpf_prog_run512+0x70/0xa0 kernel/bpf/core.c:2043
 bpf_dispatcher_nop_func include/linux/bpf.h:964 [inline]
 __bpf_prog_run include/linux/filter.h:600 [inline]
 bpf_prog_run include/linux/filter.h:607 [inline]
 bpf_test_run+0x1eb/0x410 net/bpf/test_run.c:402
 bpf_prog_test_run_skb+0x76b/0x9f0 net/bpf/test_run.c:1182
 bpf_prog_test_run+0x22a/0x250 kernel/bpf/syscall.c:3630
 __sys_bpf+0x38a/0x630 kernel/bpf/syscall.c:4983
 __do_sys_bpf kernel/bpf/syscall.c:5069 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:5067 [inline]
 __x64_sys_bpf+0x3f/0x50 kernel/bpf/syscall.c:5067
 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+0x63/0xcd

read-write to 0xffff888122fb7168 of 8 bytes by task 10536 on cpu 0:
 iptunnel_xmit_stats include/net/ip_tunnels.h:483 [inline]
 iptunnel_xmit+0x405/0x470 net/ipv4/ip_tunnel_core.c:87
 ip_tunnel_xmit+0x1631/0x16f0 net/ipv4/ip_tunnel.c:813
 __gre_xmit net/ipv4/ip_gre.c:469 [inline]
 ipgre_xmit+0x51b/0x580 net/ipv4/ip_gre.c:661
 __netdev_start_xmit include/linux/netdevice.h:4840 [inline]
 netdev_start_xmit include/linux/netdevice.h:4854 [inline]
 xmit_one+0xc0/0x2a0 net/core/dev.c:3590
 dev_hard_start_xmit+0x72/0x120 net/core/dev.c:3606
 __dev_queue_xmit+0x84c/0xfe0 net/core/dev.c:4256
 dev_queue_xmit include/linux/netdevice.h:3008 [inline]
 __bpf_tx_skb net/core/filter.c:2116 [inline]
 __bpf_redirect_no_mac net/core/filter.c:2141 [inline]
 __bpf_redirect+0x55a/0x820 net/core/filter.c:2164
 ____bpf_clone_redirect net/core/filter.c:2431 [inline]
 bpf_clone_redirect+0x168/0x1c0 net/core/filter.c:2403
 ___bpf_prog_run+0x278/0x2da0 kernel/bpf/core.c:1818
 __bpf_prog_run512+0x70/0xa0 kernel/bpf/core.c:2043
 bpf_dispatcher_nop_func include/linux/bpf.h:964 [inline]
 __bpf_prog_run include/linux/filter.h:600 [inline]
 bpf_prog_run include/linux/filter.h:607 [inline]
 bpf_test_run+0x1eb/0x410 net/bpf/test_run.c:402
 bpf_prog_test_run_skb+0x76b/0x9f0 net/bpf/test_run.c:1182
 bpf_prog_test_run+0x22a/0x250 kernel/bpf/syscall.c:3630
 __sys_bpf+0x38a/0x630 kernel/bpf/syscall.c:4983
 __do_sys_bpf kernel/bpf/syscall.c:5069 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:5067 [inline]
 __x64_sys_bpf+0x3f/0x50 kernel/bpf/syscall.c:5067
 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+0x63/0xcd

value changed: 0x000000000000010f -> 0x0000000000000110

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 10536 Comm: syz-executor.3 Not tainted 6.1.0-rc4-syzkaller-00015-gf141df371335-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
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syz-executor.3 (10536) used greatest stack depth: 10208 bytes left