[PATCH 1/3] Revert "perf session: Fix decompression of PERF_RECORD_COMPRESSED records"

Petr Malat
2020-11-24T10:00:28Z

Both mmapped and compressed events can be split by the buffer boundary,
it doesn't make sense to handle them differently.

Fixes: bb1835a3b86c ("perf session: Fix decompression of PERF_RECORD_COMPRESSED records")
Fixes: 57fc032ad643 ("perf session: Avoid infinite loop when seeing invalid header.size")
Signed-off-by: Petr Malat <oss@malat.biz>
---
tools/perf/util/session.c | 44 +++++++++++++++------------------------
1 file changed, 17 insertions(+), 27 deletions(-)

diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
index 7a5f03764702..593d5a823eba 100644
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -2024,8 +2024,8 @@ static int __perf_session__process_pipe_events(struct perf_session *session)
}

static union perf_event *
-prefetch_event(char *buf, u64 head, size_t mmap_size,
- bool needs_swap, union perf_event *error)
+fetch_mmaped_event(struct perf_session *session,
+ u64 head, size_t mmap_size, char *buf)
{
union perf_event *event;

@@ -2037,32 +2037,20 @@ prefetch_event(char *buf, u64 head, size_t mmap_size,
return NULL;

event = (union perf_event *)(buf + head);
- if (needs_swap)
- perf_event_header__bswap(&event->header);
-
- if (head + event->header.size <= mmap_size)
- return event;

- /* We're not fetching the event so swap back again */
- if (needs_swap)
+ if (session->header.needs_swap)
perf_event_header__bswap(&event->header);

- pr_debug("%s: head=%#" PRIx64 " event->header_size=%#x, mmap_size=%#zx:"
- " fuzzed or compressed perf.data?\n",__func__, head, event->header.size, mmap_size);
-
- return error;
-}
-
-static union perf_event *
-fetch_mmaped_event(u64 head, size_t mmap_size, char *buf, bool needs_swap)
-{
- return prefetch_event(buf, head, mmap_size, needs_swap, ERR_PTR(-EINVAL));
-}
+ if (head + event->header.size > mmap_size) {
+ /* We're not fetching the event so swap back again */
+ if (session->header.needs_swap)
+ perf_event_header__bswap(&event->header);
+ pr_debug("%s: head=%#" PRIx64 " event->header_size=%#x, mmap_size=%#zx: fuzzed perf.data?\n",
+ __func__, head, event->header.size, mmap_size);
+ return ERR_PTR(-EINVAL);
+ }

-static union perf_event *
-fetch_decomp_event(u64 head, size_t mmap_size, char *buf, bool needs_swap)
-{
- return prefetch_event(buf, head, mmap_size, needs_swap, NULL);
+ return event;
}

static int __perf_session__process_decomp_events(struct perf_session *session)
@@ -2075,8 +2063,10 @@ static int __perf_session__process_decomp_events(struct perf_session *session)
return 0;

while (decomp->head < decomp->size && !session_done()) {
- union perf_event *event = fetch_decomp_event(decomp->head, decomp->size, decomp->data,
- session->header.needs_swap);
+ union perf_event *event = fetch_mmaped_event(session, decomp->head, decomp->size, decomp->data);
+
+ if (IS_ERR(event))
+ return PTR_ERR(event);

if (!event)
break;
@@ -2176,7 +2166,7 @@ reader__process_events(struct reader *rd, struct perf_session *session,
}

more:
- event = fetch_mmaped_event(head, mmap_size, buf, session->header.needs_swap);
+ event = fetch_mmaped_event(session, head, mmap_size, buf);
if (IS_ERR(event))
return PTR_ERR(event);

--
2.20.1