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BUG: KCSAN: data-race in fifo_open / wait_for_partner

read-write to 0xffff88811b123664 of 4 bytes by task 7945 on cpu 0:
 fifo_open+0x89/0x5b0 fs/pipe.c:1213
 do_dentry_open+0x49f/0xa60 fs/open.c:996
 vfs_open+0x37/0x1e0 fs/open.c:1101
 do_open fs/namei.c:4837 [inline]
 path_openat+0xc01/0x10d0 fs/namei.c:5000
 do_file_open+0x16c/0x290 fs/namei.c:5029
 do_sys_openat2+0xa0/0x130 fs/open.c:1417
 do_sys_open fs/open.c:1423 [inline]
 __do_sys_openat fs/open.c:1439 [inline]
 __se_sys_openat fs/open.c:1434 [inline]
 __x64_sys_openat+0xf2/0x120 fs/open.c:1434
 x64_sys_call+0x1f72/0x2550 arch/x86/include/generated/asm/syscalls_64.h:258
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x112/0x360 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff88811b123664 of 4 bytes by task 7940 on cpu 1:
 pipe_lock fs/pipe.c:90 [inline]
 wait_for_partner+0x109/0x1d0 fs/pipe.c:1190
 fifo_open+0x443/0x5b0 fs/pipe.c:1257
 do_dentry_open+0x49f/0xa60 fs/open.c:996
 vfs_open+0x37/0x1e0 fs/open.c:1101
 do_open fs/namei.c:4837 [inline]
 path_openat+0xc01/0x10d0 fs/namei.c:5000
 do_file_open+0x16c/0x290 fs/namei.c:5029
 do_sys_openat2+0xa0/0x130 fs/open.c:1417
 __do_sys_openat2 fs/open.c:1466 [inline]
 __se_sys_openat2+0x193/0x1f0 fs/open.c:1442
 __x64_sys_openat2+0x55/0x70 fs/open.c:1442
 x64_sys_call+0x196c/0x2550 arch/x86/include/generated/asm/syscalls_64.h:438
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x112/0x360 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00000001 -> 0x00000002

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 7940 Comm: syz.7.1218 Not tainted syzkaller #0 PREEMPT(lazy) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
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