syzbot

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BUG: KCSAN: data-race in opipe_prep / pipe_write

write to 0xffff88810829b290 of 4 bytes by task 21549 on cpu 1:
 pipe_write+0x441/0xcd0 fs/pipe.c:517
 call_write_iter include/linux/fs.h:2114 [inline]
 new_sync_write fs/read_write.c:518 [inline]
 vfs_write+0x69d/0x770 fs/read_write.c:605
 ksys_write+0xce/0x180 fs/read_write.c:658
 __do_sys_write fs/read_write.c:670 [inline]
 __se_sys_write fs/read_write.c:667 [inline]
 __x64_sys_write+0x3e/0x50 fs/read_write.c:667
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff88810829b290 of 4 bytes by task 21550 on cpu 0:
 opipe_prep+0x26/0x200 fs/splice.c:1407
 splice_pipe_to_pipe fs/splice.c:1454 [inline]
 do_splice+0x2ee/0xd30 fs/splice.c:1054
 __do_splice fs/splice.c:1144 [inline]
 __do_sys_splice fs/splice.c:1350 [inline]
 __se_sys_splice+0x2a6/0x390 fs/splice.c:1332
 __x64_sys_splice+0x74/0x80 fs/splice.c:1332
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x00000010 -> 0x0000001f

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 21550 Comm: syz-executor.1 Tainted: G        W         5.14.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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