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perf synthetic events: Avoid write of uninitialized memory when generating PERF_RECORD_MMAP* records

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Account for alignment bytes in the zero-ing memset.

Fixes: 1a853e36871b533c ("perf record: Allow specifying a pid to record")
Signed-off-by: Ian Rogers <irogers@google.com>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lore.kernel.org/lkml/20210309234945.419254-1-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Ian Rogers 2021-03-09 15:49:45 -08:00 committed by Arnaldo Carvalho de Melo
parent 49f2675f5b
commit 2a76f6de07
1 changed files with 5 additions and 4 deletions
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9
tools/perf/util/synthetic-events.c
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@ -424,7 +424,7 @@ int perf_event__synthesize_mmap_events(struct perf_tool *tool,
while (!io.eof) {
static const char anonstr[] = "//anon";
size_t size;
size_t size, aligned_size;
/* ensure null termination since stack will be reused. */
event->mmap2.filename[0] = '\0';
@ -484,11 +484,12 @@ out:
}
size = strlen(event->mmap2.filename) + 1;
size = PERF_ALIGN(size, sizeof(u64));
aligned_size = PERF_ALIGN(size, sizeof(u64));
event->mmap2.len -= event->mmap.start;
event->mmap2.header.size = (sizeof(event->mmap2) -
(sizeof(event->mmap2.filename) - size));
memset(event->mmap2.filename + size, 0, machine->id_hdr_size);
(sizeof(event->mmap2.filename) - aligned_size));
memset(event->mmap2.filename + size, 0, machine->id_hdr_size +
(aligned_size - size));
event->mmap2.header.size += machine->id_hdr_size;
event->mmap2.pid = tgid;
event->mmap2.tid = pid;