2ac05f8f2e
While enabling branch stack for an event, BHRB (Branch History
Rolling Buffer) filter is set using bhrb_filter_map() callback.
This callback is not defined for cases like generic_compat_pmu
or in case where there is no PMU registered. A fix was added
in kernel to address a crash issue observed while enabling branch
stack for environments which doesn't have this callback.
commit b460b512417a ("powerpc/perf: Fix crashes with
generic_compat_pmu & BHRB").
Add perf sampling test to exercise this code path and make
sure enabling branch stack shouldn't crash in any platform.
Testcase uses software event cycles since software event is
available and can be used even in cases without PMU.
Signed-off-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220610134113.62991-11-atrajeev@linux.vnet.ibm.com
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.