syzbot

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BUG: KCSAN: data-race in fifo_open / wait_for_partner

read-write to 0xffff888126ee9c6c of 4 bytes by task 8447 on cpu 0:
 put_pipe_info fs/pipe.c:706 [inline]
 fifo_open+0x2a6/0x5e0 fs/pipe.c:1219
 do_dentry_open+0x5b3/0x930 fs/open.c:920
 vfs_open+0x47/0x50 fs/open.c:1051
 do_open fs/namei.c:3636 [inline]
 path_openat+0x17e6/0x1d00 fs/namei.c:3791
 do_filp_open+0xf6/0x200 fs/namei.c:3818
 do_sys_openat2+0xb5/0x2a0 fs/open.c:1356
 do_sys_open fs/open.c:1372 [inline]
 __do_sys_open fs/open.c:1380 [inline]
 __se_sys_open fs/open.c:1376 [inline]
 __x64_sys_open+0xe6/0x110 fs/open.c:1376
 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 0xffff888126ee9c6c of 4 bytes by task 8449 on cpu 1:
 pipe_lock_nested fs/pipe.c:81 [inline]
 pipe_lock fs/pipe.c:90 [inline]
 wait_for_partner+0x105/0x1d0 fs/pipe.c:1086
 fifo_open+0x483/0x5e0 fs/pipe.c:1153
 do_dentry_open+0x5b3/0x930 fs/open.c:920
 vfs_open+0x47/0x50 fs/open.c:1051
 do_open fs/namei.c:3636 [inline]
 path_openat+0x17e6/0x1d00 fs/namei.c:3791
 do_filp_open+0xf6/0x200 fs/namei.c:3818
 do_sys_openat2+0xb5/0x2a0 fs/open.c:1356
 do_sys_open fs/open.c:1372 [inline]
 __do_sys_open fs/open.c:1380 [inline]
 __se_sys_open fs/open.c:1376 [inline]
 __x64_sys_open+0xe6/0x110 fs/open.c:1376
 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: 0x00000002 -> 0x00000001

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 8449 Comm: syz-executor.4 Not tainted 6.4.0-rc4-syzkaller-00078-g929ed21dfdb6 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/25/2023
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