On Mon, Nov 02, 2020 at 12:36:48PM +0100, Pavel Machek wrote:
Hi!
perf failures are as usual. powerpc:
Regarding the perf failures, do you plan to revert b801d568c7d8 ("perf cs-etm: Move definition of 'traceid_list' global variable from header file") included in 4.19.152 or is a bugfix underway?
The problem is:
In file included from util/evlist.h:15:0, from util/evsel.c:30: 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 /usr/include/stdlib.h:563:13: note: expected ‘void *’ but argument is of type ‘const char *’ extern void free (void *__ptr) __THROW;
This is seen with older versions of gcc (6.5.0 in my case). I have no idea why newer versions of gcc/glibc accept this (afaics free() still expects a char *, not a const char *). The underlying problem is that pmu_name should not be declared const char *, but char *, since it is allocated. The upstream version of perf no longer uses the same definition of zfree(). It was changed from #define zfree(ptr) ({ free(*ptr); *ptr = NULL; }) to #define zfree(ptr) __zfree((void **)(ptr)) which does the necessary typecast. The fix would be to either change the definition of zfree to add the typecast, or to change the definition of pmu_name to drop the const. Both would only apply to v4.19.y. I don't know if either would be acceptable.
As the problem is already fixed in the mainline, either solution should be acceptable for -stable.
Probably the one adjusting the zfree() is more suitable, as that is the way it was solved in the mainline.
If you can provide the proper patches backported to 4.19, I will gladly take them. I tried to figure it out and couldn't, so good luck!
greg k-h