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BUG: KCSAN: data-race in fifo_open / wait_for_partner

read-write to 0xffff88811bc8f7e4 of 4 bytes by task 6887 on cpu 1:
 fifo_open+0x89/0x5b0 fs/pipe.c:1230
 do_dentry_open+0x49f/0xa60 fs/open.c:947
 vfs_open+0x37/0x1e0 fs/open.c:1052
 do_open fs/namei.c:4700 [inline]
 path_openat+0x1b39/0x2000 fs/namei.c:4863
 do_file_open_root+0x233/0x430 fs/namei.c:4916
 file_open_root+0xfd/0x130 fs/open.c:1355
 file_open_handle fs/fhandle.c:424 [inline]
 do_handle_open+0x6e6/0x7c0 fs/fhandle.c:437
 __do_sys_open_by_handle_at fs/fhandle.c:460 [inline]
 __se_sys_open_by_handle_at fs/fhandle.c:451 [inline]
 __x64_sys_open_by_handle_at+0x44/0x50 fs/fhandle.c:451
 x64_sys_call+0x153d/0x3020 arch/x86/include/generated/asm/syscalls_64.h:305
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x136/0x3c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff88811bc8f7e4 of 4 bytes by task 6893 on cpu 0:
 pipe_unlock fs/pipe.c:97 [inline]
 wait_for_partner+0xc9/0x1d0 fs/pipe.c:1204
 fifo_open+0x443/0x5b0 fs/pipe.c:1274
 do_dentry_open+0x49f/0xa60 fs/open.c:947
 vfs_open+0x37/0x1e0 fs/open.c:1052
 do_open fs/namei.c:4700 [inline]
 path_openat+0x1b39/0x2000 fs/namei.c:4863
 do_file_open+0x16c/0x290 fs/namei.c:4892
 do_sys_openat2+0xa0/0x130 fs/open.c:1368
 do_sys_open fs/open.c:1374 [inline]
 __do_sys_openat fs/open.c:1390 [inline]
 __se_sys_openat fs/open.c:1385 [inline]
 __x64_sys_openat+0xf2/0x120 fs/open.c:1385
 x64_sys_call+0x1e39/0x3020 arch/x86/include/generated/asm/syscalls_64.h:258
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x136/0x3c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00000001 -> 0x00000002

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 6893 Comm: syz.4.745 Not tainted syzkaller #0 PREEMPT(lazy) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
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