linux-kernel - [tip:perf/core] perf jit: Make perf skip unknown records

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Date:   Mon, 24 Oct 2016 11:59:37 -0700
From:   tip-bot for Stefano Sanfilippo <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     acme@...hat.com, peterz@...radead.org, namhyung@...nel.org,
        jolsa@...hat.com, mingo@...nel.org, anton@...abs.org,
        linux-kernel@...r.kernel.org, rmcilroy@...omium.org, hpa@...or.com,
        eranian@...gle.com, tglx@...utronix.de, ssanfilippo@...omium.org
Subject: [tip:perf/core] perf jit: Make perf skip unknown records

Commit-ID:  7354ec7a86c0cc03bebb7f86af8f20a88b27c262
Gitweb:     http://git.kernel.org/tip/7354ec7a86c0cc03bebb7f86af8f20a88b27c262
Author:     Stefano Sanfilippo <ssanfilippo@...omium.org>
AuthorDate: Thu, 13 Oct 2016 03:59:38 -0700
Committer:  Arnaldo Carvalho de Melo <acme@...hat.com>
CommitDate: Mon, 24 Oct 2016 11:07:38 -0300

perf jit: Make perf skip unknown records

The behavior before this commit was to skip the remaining portion of the
jitdump in case an unknown record was found, including those records
that perf could handle.

With this change, parsing a record with an unknown id will cause a
warning to be emitted, the record will be skipped and parsing will
resume from the next (valid) one.

The patch aims at making perf more future proof, by extracting as much
information as possible from jitdumps.

Signed-off-by: Stefano Sanfilippo <ssanfilippo@...omium.org>
Signed-off-by: Ross McIlroy <rmcilroy@...omium.org>
Reviewed-by: Stephane Eranian <eranian@...gle.com>
Cc: Anton Blanchard <anton@...abs.org>
Cc: Jiri Olsa <jolsa@...hat.com>
Cc: Namhyung Kim <namhyung@...nel.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Link: http://lkml.kernel.org/r/1476356383-30100-5-git-send-email-eranian@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@...hat.com>
---
 tools/perf/util/jitdump.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/tools/perf/util/jitdump.c b/tools/perf/util/jitdump.c
index f3ed3c9..75b66bb 100644
--- a/tools/perf/util/jitdump.c
+++ b/tools/perf/util/jitdump.c
@@ -263,8 +263,7 @@ jit_get_next_entry(struct jit_buf_desc *jd)
 		return NULL;
 
 	if (id >= JIT_CODE_MAX) {
-		pr_warning("next_entry: unknown prefix %d, skipping\n", id);
-		return NULL;
+		pr_warning("next_entry: unknown record type %d, skipping\n", id);
 	}
 	if (bs > jd->bufsize) {
 		void *n;
@@ -322,7 +321,8 @@ jit_get_next_entry(struct jit_buf_desc *jd)
 		break;
 	case JIT_CODE_MAX:
 	default:
-		return NULL;
+		/* skip unknown record (we have read them) */
+		break;
 	}
 	return jr;
 }