syzbot

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BUG: KCSAN: data-race in __dev_change_flags / tun_get_user

read-write to 0xffff8881668380c0 of 4 bytes by task 28912 on cpu 1:
 __dev_change_flags+0xa3/0x400 net/core/dev.c:8571
 dev_change_flags+0x59/0xd0 net/core/dev.c:8669
 devinet_ioctl+0x517/0xeb0 net/ipv4/devinet.c:1167
 inet_ioctl+0x2f4/0x3a0 net/ipv4/af_inet.c:990
 packet_ioctl+0x235/0x270 net/packet/af_packet.c:4253
 sock_do_ioctl+0x7d/0x250 net/socket.c:1202
 sock_ioctl+0x460/0x630 net/socket.c:1321
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:871 [inline]
 __se_sys_ioctl+0xcf/0x140 fs/ioctl.c:857
 __x64_sys_ioctl+0x43/0x50 fs/ioctl.c:857
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

read to 0xffff8881668380c0 of 4 bytes by task 28914 on cpu 0:
 tun_get_user+0x1a15/0x22b0 drivers/net/tun.c:1944
 tun_chr_write_iter+0x18e/0x240 drivers/net/tun.c:2048
 call_write_iter include/linux/fs.h:1985 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x4ab/0x7d0 fs/read_write.c:584
 ksys_write+0xeb/0x1a0 fs/read_write.c:637
 __do_sys_write fs/read_write.c:649 [inline]
 __se_sys_write fs/read_write.c:646 [inline]
 __x64_sys_write+0x42/0x50 fs/read_write.c:646
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 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: 28914 Comm: syz-executor.4 Tainted: G        W          6.5.0-syzkaller-12053-g744a759492b5 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
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