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BUG: KCSAN: data-race in do_sendfile / ksys_write

write to 0xffff88813909b068 of 8 bytes by task 24979 on cpu 0:
 ksys_write+0x11b/0x1a0 fs/read_write.c:646
 __do_sys_write fs/read_write.c:656 [inline]
 __se_sys_write fs/read_write.c:653 [inline]
 __x64_sys_write+0x3e/0x50 fs/read_write.c:653
 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+0x44/0xae

write to 0xffff88813909b068 of 8 bytes by task 24980 on cpu 1:
 do_sendfile+0x705/0x900 fs/read_write.c:1258
 __do_sys_sendfile64 fs/read_write.c:1305 [inline]
 __se_sys_sendfile64 fs/read_write.c:1297 [inline]
 __x64_sys_sendfile64+0xb9/0x150 fs/read_write.c:1297
 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+0x44/0xae

value changed: 0x0000000000000484 -> 0x0000000000000088

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 24980 Comm: syz-executor.1 Not tainted 5.18.0-rc5-syzkaller-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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