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Commit 872c8ee8 authored by Alexey Budankov's avatar Alexey Budankov Committed by Arnaldo Carvalho de Melo
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perf session: Fix loading of compressed data split across adjacent records 



Fix decompression failure found during the loading of compressed trace
collected on larger scale systems (>48 cores).

The error happened due to lack of decompression space for a mmaped
buffer data chunk split across adjacent PERF_RECORD_COMPRESSED records.

  $ perf report -i bt.16384.data --stats
  failed to decompress (B): 63869 -> 0 : Destination buffer is too small
  user stack dump failure
  Can't parse sample, err = -14
  0x2637e436 [0x4080]: failed to process type: 9
  Error:
  failed to process sample

  $ perf test 71
  71: Zstd perf.data compression/decompression              : Ok

Signed-off-by: default avatarAlexey Budankov <alexey.budankov@linux.intel.com>
Acked-by: default avatarJiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/4d839e1b-9c48-89c4-9702-a12217420611@linux.intel.com


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 146540fb

tools/perf/util/session.c

+14 −8
Original line number Diff line number Diff line
@@ -36,10 +36,16 @@ static int perf_session__process_compressed_event(struct perf_session *session, 
	void *src;

	size_t decomp_size, src_size;

	u64 decomp_last_rem = 0;

	size_t decomp_len = session->header.env.comp_mmap_len;

	size_t mmap_len, decomp_len = session->header.env.comp_mmap_len;

	struct decomp *decomp, *decomp_last = session->decomp_last;



	decomp = mmap(NULL, sizeof(struct decomp) + decomp_len, PROT_READ|PROT_WRITE,

	if (decomp_last) {

		decomp_last_rem = decomp_last->size - decomp_last->head;

		decomp_len += decomp_last_rem;

	}



	mmap_len = sizeof(struct decomp) + decomp_len;

	decomp = mmap(NULL, mmap_len, PROT_READ|PROT_WRITE,

		      MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);

	if (decomp == MAP_FAILED) {

		pr_err("Couldn't allocate memory for decompression\n");
@@ -47,10 +53,10 @@ static int perf_session__process_compressed_event(struct perf_session *session, 
	}



	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);

	} while (1);

}

tools/perf/util/session.h

+1 −0
Original line number Diff line number Diff line
@@ -46,6 +46,7 @@ struct perf_session { 
struct decomp {

	struct decomp *next;

	u64 file_pos;

	size_t mmap_len;

	u64 head;

	size_t size;

	char data[];

tools/perf/util/zstd.c

+2 −2
Original line number Diff line number Diff line
@@ -99,8 +99,8 @@ size_t zstd_decompress_stream(struct zstd_data *data, void *src, size_t src_size 
	while (input.pos < input.size) {

		ret = ZSTD_decompressStream(data->dstream, &output, &input);

		if (ZSTD_isError(ret)) {

			pr_err("failed to decompress (B): %ld -> %ld : %s\n",

			       src_size, output.size, ZSTD_getErrorName(ret));

			pr_err("failed to decompress (B): %ld -> %ld, dst_size %ld : %s\n",

			       src_size, output.size, dst_size, ZSTD_getErrorName(ret));

			break;

		}

		output.dst  = dst + output.pos;