234f0337b4
[ Upstream commit 6407cf533217e09dfd895e64984c3f1ee3802373 ]
Since a7c01fa93aeb ("signal: break out of wait loops on kthread_stop()")
kthread_stop() started asserting a pending signal which wreaks havoc with
a few of our selftests. Mainly because they are not fully expecting to
handle signals, but also cutting the intended test runtimes short due
signal_pending() now returning true (via __igt_timeout), which therefore
breaks both the patterns of:
kthread_run()
..sleep for igt_timeout_ms to allow test to exercise stuff..
kthread_stop()
And check for errors recorded in the thread.
And also:
Main thread | Test thread
---------------+------------------------------
kthread_run() |
kthread_stop() | do stuff until __igt_timeout
| -- exits early due signal --
Where this kthread_stop() was assume would have a "join" semantics, which
it would have had if not the new signal assertion issue.
To recap, threads are now likely to catch a previously impossible
ERESTARTSYS or EINTR, marking the test as failed, or have a pointlessly
short run time.
To work around this start using kthread_work(er) API which provides
an explicit way of waiting for threads to exit. And for cases where
parent controls the test duration we add explicit signaling which threads
will now use instead of relying on kthread_should_stop().
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221020130841.3845791-1-tvrtko.ursulin@linux.intel.com
Stable-dep-of: 79d0150d2d98 ("drm/i915/selftests: Add some missing error propagation")
Signed-off-by: Sasha Levin <sashal@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.