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authorAdrian Hunter <adrian.hunter@intel.com>2022-09-14 15:24:29 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2022-09-28 12:04:07 +0300
commit67199c26a006ec999a5030d653eb3e229831f84a (patch)
tree2a2e6a89d3c0679c5391e267b906762605d2686d
parent80b2f37b3370c505b03544b5efc895514f673cf3 (diff)
downloadlinux-67199c26a006ec999a5030d653eb3e229831f84a.tar.xz
perf kcore_copy: Do not check /proc/modules is unchanged
[ Upstream commit 5b427df27b94aec1312cace48a746782a0925c53 ] /proc/kallsyms and /proc/modules are compared before and after the copy in order to ensure no changes during the copy. However /proc/modules also might change due to reference counts changing even though that does not make any difference. Any modules loaded or unloaded should be visible in changes to kallsyms, so it is not necessary to check /proc/modules also anyway. Remove the comparison checking that /proc/modules is unchanged. Fixes: fc1b691d7651d949 ("perf buildid-cache: Add ability to add kcore to the cache") Reported-by: Daniel Dao <dqminh@cloudflare.com> Signed-off-by: Adrian Hunter <adrian.hunter@intel.com> Tested-by: Daniel Dao <dqminh@cloudflare.com> Acked-by: Namhyung Kim <namhyung@kernel.org> Cc: Ian Rogers <irogers@google.com> Cc: Jiri Olsa <jolsa@kernel.org> Link: https://lore.kernel.org/r/20220914122429.8770-1-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
-rw-r--r--tools/perf/util/symbol-elf.c7
1 files changed, 2 insertions, 5 deletions
diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c
index a04a7dfb8ec0..f15258fbe9db 100644
--- a/tools/perf/util/symbol-elf.c
+++ b/tools/perf/util/symbol-elf.c
@@ -1912,8 +1912,8 @@ static int kcore_copy__compare_file(const char *from_dir, const char *to_dir,
* unusual. One significant peculiarity is that the mapping (start -> pgoff)
* is not the same for the kernel map and the modules map. That happens because
* the data is copied adjacently whereas the original kcore has gaps. Finally,
- * kallsyms and modules files are compared with their copies to check that
- * modules have not been loaded or unloaded while the copies were taking place.
+ * kallsyms file is compared with its copy to check that modules have not been
+ * loaded or unloaded while the copies were taking place.
*
* Return: %0 on success, %-1 on failure.
*/
@@ -1976,9 +1976,6 @@ int kcore_copy(const char *from_dir, const char *to_dir)
goto out_extract_close;
}
- if (kcore_copy__compare_file(from_dir, to_dir, "modules"))
- goto out_extract_close;
-
if (kcore_copy__compare_file(from_dir, to_dir, "kallsyms"))
goto out_extract_close;