[PATCH v2 0/3] perf record: fix multi-record Zstd compression

[Dmitry Ilvokhin <d@ilvokhin.com>]

Patch 1 fixes a 'perf record -z' regression that aborts recording with
"Bad address" and produces an undecompressable perf.data.

While fixing it I found two more latent bugs in the same compressor,
zstd_compress_stream_to_records(): an output-buffer overrun and a broken
zstd-error fallback. Addressed in patches 2 and 3.

v1 -> v2:

- Patch 2 ("perf record: Avoid overrunning the zstd output buffer"):
  rework the overly strict output buffer check to pass the remaining dst
  size to process_comp_header() and bail only when a record won't fit
  (Sashiko).

v1: https://lore.kernel.org/all/cover.1781797544.git.d@ilvokhin.com/

Dmitry Ilvokhin (3):
  perf record: Fix multiple PERF_RECORD_COMPRESSED2 records per push
  perf record: Avoid overrunning the zstd output buffer
  perf record: Don't store raw data on zstd compression failure

 tools/perf/builtin-record.c                   | 48 ++++++++------
 .../record+zstd_comp_decomp_multi_record.sh   | 64 +++++++++++++++++++
 tools/perf/util/compress.h                    |  6 +-
 tools/perf/util/zstd.c                        | 28 +++++---
 4 files changed, 116 insertions(+), 30 deletions(-)
 create mode 100755 tools/perf/tests/shell/record+zstd_comp_decomp_multi_record.sh

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