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SubjectRe: [PATCH v1] perf session: fix loading of compressed data split across adjacent records
Em Mon, Jul 15, 2019 at 03:30:24PM +0300, Alexey Budankov escreveu:
> On 14.07.2019 18:49, Jiri Olsa wrote:
> > On Tue, Jul 09, 2019 at 05:48:14PM +0300, Alexey Budankov wrote:
> >
> > SNIP
> >
> >> decomp->file_pos = file_offset;
> >> + decomp->mmap_len = mmap_len;
> >> decomp->head = 0;
> >>
> >> - if (decomp_last) {
> >> - decomp_last_rem = decomp_last->size - decomp_last->head;
> >> + if (decomp_last_rem) {
> >> memcpy(decomp->data, &(decomp_last->data[decomp_last->head]), decomp_last_rem);
> >> decomp->size = decomp_last_rem;
> >> }
> >> @@ -61,7 +67,7 @@ static int perf_session__process_compressed_event(struct perf_session *session,
> >> decomp_size = zstd_decompress_stream(&(session->zstd_data), src, src_size,
> >> &(decomp->data[decomp_last_rem]), decomp_len - decomp_last_rem);
> >> if (!decomp_size) {
> >> - munmap(decomp, sizeof(struct decomp) + decomp_len);
> >> + munmap(decomp, mmap_len);
> >> pr_err("Couldn't decompress data\n");
> >> return -1;
> >> }
> >> @@ -255,15 +261,15 @@ static void perf_session__delete_threads(struct perf_session *session)
> >> static void perf_session__release_decomp_events(struct perf_session *session)
> >> {
> >> struct decomp *next, *decomp;
> >> - size_t decomp_len;
> >> + size_t mmap_len;
> >> next = session->decomp;
> >> - decomp_len = session->header.env.comp_mmap_len;
> >> do {
> >> decomp = next;
> >> if (decomp == NULL)
> >> break;
> >> next = decomp->next;
> >> - munmap(decomp, decomp_len + sizeof(struct decomp));
> >> + mmap_len = decomp->mmap_len;
> >> + munmap(decomp, mmap_len);
> >
> > what's the need for extra mmap_len variable in here?
> > could you just use decomp->mmap_len directly?
>
> To avoid reference to the object being deallocated.
> Plain munmap(), yes - :)

So, Jiri, Acked-by?

- Arnaldo

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