syzbot

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BUG: KCSAN: data-race in put_pipe_info / wait_for_partner

write to 0xffff888100c6c2ac of 4 bytes by task 11670 on cpu 0:
 put_pipe_info+0x3d/0xe0 fs/pipe.c:706
 fifo_open+0x342/0x6a0 fs/pipe.c:1214
 do_dentry_open+0x529/0x850 fs/open.c:826
 vfs_open+0x43/0x50 fs/open.c:949
 do_open fs/namei.c:3374 [inline]
 path_openat+0x1787/0x1f20 fs/namei.c:3507
 do_filp_open+0xe9/0x200 fs/namei.c:3534
 do_sys_openat2+0xa3/0x250 fs/open.c:1204
 do_sys_open fs/open.c:1220 [inline]
 __do_sys_openat fs/open.c:1236 [inline]
 __se_sys_openat fs/open.c:1231 [inline]
 __x64_sys_openat+0xef/0x110 fs/open.c:1231
 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 0xffff888100c6c2ac of 4 bytes by task 11681 on cpu 1:
 pipe_lock_nested fs/pipe.c:80 [inline]
 pipe_lock fs/pipe.c:89 [inline]
 wait_for_partner+0xe0/0x1d0 fs/pipe.c:1081
 fifo_open+0x503/0x6a0 fs/pipe.c:1148
 do_dentry_open+0x529/0x850 fs/open.c:826
 vfs_open+0x43/0x50 fs/open.c:949
 do_open fs/namei.c:3374 [inline]
 path_openat+0x1787/0x1f20 fs/namei.c:3507
 do_filp_open+0xe9/0x200 fs/namei.c:3534
 do_sys_openat2+0xa3/0x250 fs/open.c:1204
 do_sys_open fs/open.c:1220 [inline]
 __do_sys_open fs/open.c:1228 [inline]
 __se_sys_open fs/open.c:1224 [inline]
 __x64_sys_open+0xe2/0x110 fs/open.c:1224
 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: 0x00000002 -> 0x00000001

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 11681 Comm: syz-executor.1 Tainted: G        W         5.14.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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