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Commit bad76008 authored by Ingo Molnar's avatar Ingo Molnar
Browse files

perf_counter tools: fix infinite loop in perf-report on zeroed event records 



Bail out early if a record has zero size - we have no chance to make
reliable progress in that case. Print out the offset where this happens,
and print the number of bytes we missed out on.

Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 66cf7829

Documentation/perf_counter/perf-report.cc

+16 −2
Original line number Diff line number Diff line
@@ -13,6 +13,7 @@ 
#include <ctype.h>

#include <time.h>

#include <getopt.h>

#include <assert.h>



#include <sys/ioctl.h>

#include <sys/poll.h>
@@ -226,7 +227,7 @@ void load_kallsyms(void) 
	while (!feof(file)) {

		uint64_t start;

		char c;

		char sym[1024];

		char sym[1024000];



		if (getline(&line, &n, file) < 0)

			break;
@@ -416,12 +417,23 @@ more: 


	if (head + event->header.size >= page_size * mmap_window) {

		unsigned long shift = page_size * (head / page_size);

		int ret;



		ret = munmap(buf, page_size * mmap_window);

		assert(ret == 0);



		munmap(buf, page_size * mmap_window);

		offset += shift;

		head -= shift;

		goto remap;

	}





	if (!event->header.size) {

		fprintf(stderr, "zero-sized event at file offset %ld\n", offset + head);

		fprintf(stderr, "skipping %ld bytes of events.\n", stat.st_size - offset - head);

		goto done;

	}



	head += event->header.size;



	if (event->header.misc & PERF_EVENT_MISC_OVERFLOW) {
@@ -458,6 +470,8 @@ more: 
	if (offset + head < stat.st_size)

		goto more;



done:



	close(input);



	std::map<std::string, int>::iterator hi = hist.begin();