linux-stable.git/tools/testing/selftests/futex/include/futex_thread.h, branch master Linux kernel stable tree selftests/futex: Provide thread creation and synchronization helpers 2026-07-20T18:58:51+00:00 Yuwen Chen ywen.chen@foxmail.com 2026-05-18T02:16:40+00:00 6c4a1b972643d72bd26f674677df8b5a6a3fe94f There are timing issues in the use of threads in some selftests for futexes as the tests rely on timed waits to ensure that the other test thread[s] reached the lock wait function in the kernel. That "works" on halfways idle systems, but fails under load which results in tests failing. Provide a set of helper functions to create test threads and to wait for them to reach the lock wait by monitoring /proc/$PID/wchan. [ tglx: Fixup coding style, move the timeout into the helper, adapt to test harness changes and massage change log ] Signed-off-by: Yuwen Chen <ywen.chen@foxmail.com> Signed-off-by: Thomas Gleixner <tglx@kernel.org> Link: https://patch.msgid.link/tencent_4C90BE98BBC48B38B9FBC6A95C45CF49F309@qq.com 
There are timing issues in the use of threads in some selftests for futexes
as the tests rely on timed waits to ensure that the other test thread[s]
reached the lock wait function in the kernel.

That "works" on halfways idle systems, but fails under load which results
in tests failing.

Provide a set of helper functions to create test threads and to wait for
them to reach the lock wait by monitoring /proc/$PID/wchan.

[ tglx: Fixup coding style, move the timeout into the helper, adapt to test
  	harness changes and massage change log ]

Signed-off-by: Yuwen Chen <ywen.chen@foxmail.com>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Link: https://patch.msgid.link/tencent_4C90BE98BBC48B38B9FBC6A95C45CF49F309@qq.com