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Commit 3f5a4272 authored by Anton Blanchard's avatar Anton Blanchard Committed by Arnaldo Carvalho de Melo
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perf symbols: /proc/kallsyms does not sort module symbols 

kallsyms__parse assumes that /proc/kallsyms is sorted and sets the end
of the previous symbol to the start of the current one.

Unfortunately module symbols are not sorted, eg:

ffffffffa0081f30 t e1000_clean_rx_irq   [e1000e]
ffffffffa00817a0 t e1000_alloc_rx_buffers       [e1000e]

Some symbols end up with a negative length and others have a length
larger than they should. This results in confusing perf output.

We already have a function to fixup the end of zero length symbols so
use that instead.

Cc: Eric B Munson <emunson@mgebm.net>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20110824065242.969681349@samba.org


Signed-off-by: default avatarAnton Blanchard <anton@samba.org>
Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent adb09184

tools/perf/util/symbol.c

+11 −22
Original line number Diff line number Diff line
@@ -438,18 +438,11 @@ int kallsyms__parse(const char *filename, void *arg, 
	char *line = NULL;

	size_t n;

	int err = -1;

	u64 prev_start = 0;

	char prev_symbol_type = 0;

	char *prev_symbol_name;

	FILE *file = fopen(filename, "r");



	if (file == NULL)

		goto out_failure;



	prev_symbol_name = malloc(KSYM_NAME_LEN);

	if (prev_symbol_name == NULL)

		goto out_close;



	err = 0;



	while (!feof(file)) {
@@ -480,24 +473,18 @@ int kallsyms__parse(const char *filename, void *arg, 
			break;

		}



		if (prev_symbol_type) {

			u64 end = start;

			if (end != prev_start)

				--end;

			err = process_symbol(arg, prev_symbol_name,

					     prev_symbol_type, prev_start, end);

		/*

		 * module symbols are not sorted so we add all

		 * symbols with zero length and rely on

		 * symbols__fixup_end() to fix it up.

		 */

		err = process_symbol(arg, symbol_name,

				     symbol_type, start, start);

		if (err)

			break;

	}



		memcpy(prev_symbol_name, symbol_name, len + 1);

		prev_symbol_type = symbol_type;

		prev_start = start;

	}



	free(prev_symbol_name);

	free(line);

out_close:

	fclose(file);

	return err;
@@ -703,6 +690,8 @@ int dso__load_kallsyms(struct dso *dso, const char *filename, 
	if (dso__load_all_kallsyms(dso, filename, map) < 0)

		return -1;



	symbols__fixup_end(&dso->symbols[map->type]);



	if (dso->kernel == DSO_TYPE_GUEST_KERNEL)

		dso->symtab_type = SYMTAB__GUEST_KALLSYMS;

	else