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Commit 2bf6a49c authored by Adrian Hunter's avatar Adrian Hunter Committed by Greg Kroah-Hartman
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perf kcore_copy: Fix module map when there are no modules loaded 



[ Upstream commit 61f82e3fb697a8e85f22fdec786528af73dc36d1 ]

In the absence of any modules, no "modules" map is created, but there
are other executable pages to map, due to eBPF JIT, kprobe or ftrace.
Map them by recognizing that the first "module" symbol is not
necessarily from a module, and adjust the map accordingly.

Signed-off-by: default avatarAdrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: x86@kernel.org
Link: http://lore.kernel.org/lkml/20200512121922.8997-10-adrian.hunter@intel.com


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent ba749719

tools/perf/util/symbol-elf.c

+7 −0
Original line number Diff line number Diff line
@@ -1421,6 +1421,7 @@ struct kcore_copy_info { 
	u64 first_symbol;

	u64 last_symbol;

	u64 first_module;

	u64 first_module_symbol;

	u64 last_module_symbol;

	struct phdr_data kernel_map;

	struct phdr_data modules_map;
@@ -1435,6 +1436,8 @@ static int kcore_copy__process_kallsyms(void *arg, const char *name, char type, 
		return 0;



	if (strchr(name, '[')) {

		if (!kci->first_module_symbol || start < kci->first_module_symbol)

			kci->first_module_symbol = start;

		if (start > kci->last_module_symbol)

			kci->last_module_symbol = start;

		return 0;
@@ -1559,6 +1562,10 @@ static int kcore_copy__calc_maps(struct kcore_copy_info *kci, const char *dir, 
		kci->etext += page_size;

	}



	if (kci->first_module_symbol &&

	    (!kci->first_module || kci->first_module_symbol < kci->first_module))

		kci->first_module = kci->first_module_symbol;



	kci->first_module = round_down(kci->first_module, page_size);



	if (kci->last_module_symbol) {