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3ab5872df9
perf may fail to build in v4.19.y with the following error.
util/evsel.c: In function ‘perf_evsel__exit’:
util/util.h:25:28: error:
passing argument 1 of ‘free’ discards ‘const’ qualifier from pointer target type
This is observed (at least) with gcc v6.5.0. The underlying problem is
the following statement.
zfree(&evsel->pmu_name);
evsel->pmu_name is decared 'const *'. zfree in turn is defined as
#define zfree(ptr) ({ free(*ptr); *ptr = NULL; })
and thus passes the const * to free(). The problem is not seen
in the upstream kernel since zfree() has been rewritten there.
The problem has been introduced into v4.19.y with the backport of upstream
commit d4953f7ef1 (perf parse-events: Fix 3 use after frees found with
clang ASAN).
One possible fix of this problem would be to not declare pmu_name
as const. This patch chooses to typecast the parameter of zfree()
to void *, following the guidance from the upstream kernel which
does the same since commit 7f7c536f23 ("tools lib: Adopt
zalloc()/zfree() from tools/perf")
Fixes: a0100a3630 ("perf parse-events: Fix 3 use after frees found with clang ASAN")
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.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.
See Documentation/00-INDEX for a list of what is contained in each file.
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.