syzbot

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BUG: KCSAN: data-race in pipe_lock / pipe_release

write to 0xffff8880b6b467ec of 4 bytes by task 16474 on cpu 0:
 put_pipe_info fs/pipe.c:707 [inline]
 pipe_release+0x186/0x1e0 fs/pipe.c:737
 __fput+0x1df/0x460 fs/file_table.c:281
 ____fput+0x11/0x20 fs/file_table.c:314
 task_work_run+0x8e/0x110 kernel/task_work.c:135
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_usermode_loop arch/x86/entry/common.c:216 [inline]
 __prepare_exit_to_usermode+0x1c6/0x230 arch/x86/entry/common.c:246
 __syscall_return_slowpath+0x47/0x60 arch/x86/entry/common.c:329
 do_syscall_64+0x5d/0xb0 arch/x86/entry/common.c:368
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff8880b6b467ec of 4 bytes by task 16484 on cpu 1:
 pipe_lock_nested fs/pipe.c:65 [inline]
 pipe_lock+0x13/0x40 fs/pipe.c:74
 do_splice+0xc95/0x10c0 fs/splice.c:1170
 __do_sys_splice fs/splice.c:1419 [inline]
 __se_sys_splice fs/splice.c:1401 [inline]
 __x64_sys_splice+0xf2/0x190 fs/splice.c:1401
 do_syscall_64+0x51/0xb0 arch/x86/entry/common.c:359
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 16484 Comm: syz-executor.3 Not tainted 5.8.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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