syzbot

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

read to 0xffff8881325f3150 of 8 bytes by task 21364 on cpu 1:
 ip_tunnel_xmit+0x9ec/0x1210 net/ipv4/ip_tunnel.c:819
 __gre_xmit net/ipv4/ip_gre.c:471 [inline]
 ipgre_xmit+0x553/0x5a0 net/ipv4/ip_gre.c:658
 __netdev_start_xmit include/linux/netdevice.h:4994 [inline]
 netdev_start_xmit include/linux/netdevice.h:5008 [inline]
 xmit_one+0x105/0x2f0 net/core/dev.c:3590
 dev_hard_start_xmit net/core/dev.c:3606 [inline]
 __dev_queue_xmit+0x869/0xf70 net/core/dev.c:4229
 dev_queue_xmit+0x13/0x20 net/core/dev.c:4262
 __bpf_tx_skb net/core/filter.c:2114 [inline]
 __bpf_redirect_no_mac net/core/filter.c:2139 [inline]
 __bpf_redirect+0x5a2/0x840 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+0xc87/0x30c0 kernel/bpf/core.c:1558
 __bpf_prog_run512+0x70/0xa0 kernel/bpf/core.c:1786
 bpf_dispatcher_nop_func include/linux/bpf.h:727 [inline]
 __bpf_prog_run include/linux/filter.h:626 [inline]
 bpf_prog_run include/linux/filter.h:633 [inline]
 bpf_test_run+0x18b/0x400 net/bpf/test_run.c:120
 bpf_prog_test_run_skb+0x73d/0xed0 net/bpf/test_run.c:666
 bpf_prog_test_run kernel/bpf/syscall.c:3349 [inline]
 __sys_bpf+0x3ca4/0xa3c0 kernel/bpf/syscall.c:4651
 __do_sys_bpf kernel/bpf/syscall.c:4737 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:4735 [inline]
 __x64_sys_bpf+0x3f/0x50 kernel/bpf/syscall.c:4735
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

write to 0xffff8881325f3150 of 8 bytes by task 21367 on cpu 0:
 ip_tunnel_xmit+0x9fe/0x1210 net/ipv4/ip_tunnel.c:819
 __gre_xmit net/ipv4/ip_gre.c:471 [inline]
 ipgre_xmit+0x553/0x5a0 net/ipv4/ip_gre.c:658
 __netdev_start_xmit include/linux/netdevice.h:4994 [inline]
 netdev_start_xmit include/linux/netdevice.h:5008 [inline]
 xmit_one+0x105/0x2f0 net/core/dev.c:3590
 dev_hard_start_xmit net/core/dev.c:3606 [inline]
 __dev_queue_xmit+0x869/0xf70 net/core/dev.c:4229
 dev_queue_xmit+0x13/0x20 net/core/dev.c:4262
 __bpf_tx_skb net/core/filter.c:2114 [inline]
 __bpf_redirect_no_mac net/core/filter.c:2139 [inline]
 __bpf_redirect+0x5a2/0x840 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+0xc87/0x30c0 kernel/bpf/core.c:1558
 __bpf_prog_run512+0x70/0xa0 kernel/bpf/core.c:1786
 bpf_dispatcher_nop_func include/linux/bpf.h:727 [inline]
 __bpf_prog_run include/linux/filter.h:626 [inline]
 bpf_prog_run include/linux/filter.h:633 [inline]
 bpf_test_run+0x18b/0x400 net/bpf/test_run.c:120
 bpf_prog_test_run_skb+0x73d/0xed0 net/bpf/test_run.c:666
 bpf_prog_test_run kernel/bpf/syscall.c:3349 [inline]
 __sys_bpf+0x3ca4/0xa3c0 kernel/bpf/syscall.c:4651
 __do_sys_bpf kernel/bpf/syscall.c:4737 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:4735 [inline]
 __x64_sys_bpf+0x3f/0x50 kernel/bpf/syscall.c:4735
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x0000000000001778 -> 0x0000000000001779

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 21367 Comm: syz-executor.2 Not tainted 5.16.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================