Ingo Molnar c1f47b454c perf_counter tools: Fix vmlinux fallback when running on a different kernel ... Lucas De Marchi reported that perf report and perf annotate displays mismatching profile if a perf.data is analyzed on an older kernel - even if the correct vmlinux is specified via the -k option. The reason is the fallback path in util/symbol.c:dso__load_kernel(): int dso__load_kernel(struct dso *self, const char *vmlinux, symbol_filter_t filter, int verbose) { int err = -1; if (vmlinux) err = dso__load_vmlinux(self, vmlinux, filter, verbose); if (err) err = dso__load_kallsyms(self, filter, verbose); return err; } dso__load_vmlinux() returns negative on error, but on success it returns the number of symbols loaded - which confuses the function to load the kallsyms. This is normally harmless, as reporting is usually performed on the same kernel that is analyzed - but if there's a mismatch then we load the wrong kallsyms and create a non-sensical symbol tree. The fix is to only fall back to kallsyms on errors. Reported-by: Lucas De Marchi <lucas.de.marchi@gmail.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>		2009-06-21 13:58:51 +02:00
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perf	perf_counter tools: Fix vmlinux fallback when running on a different kernel	2009-06-21 13:58:51 +02:00