syzbot

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BUG: KCSAN: data-race in __dev_change_flags / tun_chr_poll

read-write to 0xffff8881e5dd00c0 of 4 bytes by task 9796 on cpu 1:
 __dev_change_flags+0x9e/0x3f0 net/core/dev.c:8530
 dev_change_flags+0x55/0xc0 net/core/dev.c:8627
 devinet_ioctl+0x539/0xe40 net/ipv4/devinet.c:1146
 inet_ioctl+0x215/0x2b0 net/ipv4/af_inet.c:968
 packet_ioctl+0x12a/0x180 net/packet/af_packet.c:4231
 sock_do_ioctl+0x7d/0x250 net/socket.c:1169
 sock_ioctl+0x343/0x570 net/socket.c:1286
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl+0xcb/0x140 fs/ioctl.c:856
 __x64_sys_ioctl+0x3f/0x50 fs/ioctl.c:856
 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 to 0xffff8881e5dd00c0 of 4 bytes by task 9790 on cpu 0:
 tun_sock_writeable drivers/net/tun.c:1413 [inline]
 tun_chr_poll+0x29c/0x3f0 drivers/net/tun.c:1443
 vfs_poll include/linux/poll.h:88 [inline]
 do_pollfd fs/select.c:873 [inline]
 do_poll fs/select.c:921 [inline]
 do_sys_poll+0x6d5/0xca0 fs/select.c:1015
 __do_sys_poll fs/select.c:1080 [inline]
 __se_sys_poll+0xfd/0x210 fs/select.c:1068
 __x64_sys_poll+0x3f/0x50 fs/select.c:1068
 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: 0x00001002 -> 0x00008002

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 9790 Comm: syz-executor.5 Not tainted 6.0.0-rc3-syzkaller-00007-gdcf8e5633e2e-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022
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