On 6/8/22 10:01, Stephane Eranian via perfmon2-devel wrote: > Hi, > > Could you try the attached patch? > There is no use after free in the code as far as I can tell. > But I modified the code to avoid triggering the gcc warning. > I don't have gcc-12 so let me know if this works for you.
Hi, I tried out the patch on Fedora rawhide which has gcc-12 with a rpmbuild of a git libpfm repo tarball. With the patch it builds successfully. Without the patch the build failed. Took a look at the patch and it looks reasonable. Thanks, -will > > > On Tue, Jun 7, 2022 at 1:26 AM Stephane Eranian <eran...@googlemail.com> > wrote: >> >> Hi, >> >> Thanks for the report, >> >> I will fix this in the coming days. >> >> On Sat, Jun 4, 2022 at 10:08 AM Vitaly Chikunov <v...@altlinux.org> wrote: >>> >>> Stephane, >>> >>> There is compile failure on GCC 12.1.1: >>> >>> pfmlib_perf_event_pmu.c: In function 'perf_table_alloc_event': >>> pfmlib_perf_event_pmu.c:293:47: error: pointer may be used after >>> 'realloc' [-Werror=use-after-free] >>> 293 | perf_pe_free = new_pe + (perf_pe_free - perf_pe); >>> | ^ >>> pfmlib_perf_event_pmu.c:289:18: note: call to 'realloc' here >>> 289 | new_pe = realloc(perf_pe, perf_pe_count * >>> sizeof(perf_event_t)); >>> | >>> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ >>> In function 'perf_table_alloc_umask', >>> inlined from 'gen_tracepoint_table' at pfmlib_perf_event_pmu.c:457:10: >>> pfmlib_perf_event_pmu.c:329:47: error: pointer may be used after >>> 'realloc' [-Werror=use-after-free] >>> 329 | perf_um_free = new_um + (perf_um_free - perf_um); >>> | ^ >>> pfmlib_perf_event_pmu.c:325:18: note: call to 'realloc' here >>> 325 | new_um = realloc(perf_um, perf_um_count * >>> sizeof(*new_um)); >>> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ >>> cc1: all warnings being treated as errors >>> >>> Also, pointer arithmetic on unallocated region are, perhaps, undefined >>> behavior by C standard. So even though this math looks safe on x86 this >>> should be fixed anyway to be more portable. >>> >>> Thanks, >>> >>> >>> >>> _______________________________________________ >>> perfmon2-devel mailing list >>> perfmon2-devel@lists.sourceforge.net >>> https://lists.sourceforge.net/lists/listinfo/perfmon2-devel _______________________________________________ perfmon2-devel mailing list perfmon2-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/perfmon2-devel
