[PATCH v2 1/3] Revert "perf session: Fix decompression of PERF_RECORD_COMPRESSED records"

[Petr Malat]

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 <o...@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 098080287c68..0d7a59c1aeb6 100644
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -2038,8 +2038,8 @@ 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;
 
@@ -2051,32 +2051,20 @@ 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)
@@ -2089,8 +2077,10 @@ 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;
@@ -2190,7 +2180,7 @@ 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