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From: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
To: linux-kernel@vger.kernel.org, Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>, Jiri Olsa <jolsa@redhat.com>,
	Ingo Molnar <mingo@redhat.com>, Paul Mackerras <paulus@samba.org>,
	Peter Zijlstra <a.p.zijlstra@chello.nl>
Subject: [PATCH -tip/urgent ] [BUGFIX] perf/probe: Fix a segfault if asked for variable it doesn't find
Date: Thu, 29 May 2014 19:52:32 +0900
Message-ID: <20140529105232.28251.30447.stgit@ltc230.yrl.intra.hitachi.co.jp> (raw)
In-Reply-To: <20140528214406.GE2764@kernel.org>

Fix a segfault bug by asking for variable it doesn't find.
Since the convert_variable() didn't handle error code returned
from convert_variable_location(), it just passed an incomplete
variable field and then a segfault was occured when formatting
the field.

This fixes that bug by handling success code correctly in
convert_variable(). Other callers of convert_variable_location()
are correctly checking the return code.

This bug was introduced by following commit. But another hidden
erroneous error handling has been there previuosly (-ENOMEM case).

 commit 3d918a12a1b3088ac16ff37fa52760639d6e2403

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Reported-by: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
---
 tools/perf/util/probe-finder.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index 5627621..9d8eb26 100644
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -511,12 +511,12 @@ static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
 
 	ret = convert_variable_location(vr_die, pf->addr, pf->fb_ops,
 					&pf->sp_die, pf->tvar);
-	if (ret == -ENOENT)
+	if (ret == -ENOENT || ret == -EINVAL)
 		pr_err("Failed to find the location of %s at this address.\n"
 		       " Perhaps, it has been optimized out.\n", pf->pvar->var);
 	else if (ret == -ENOTSUP)
 		pr_err("Sorry, we don't support this variable location yet.\n");
-	else if (pf->pvar->field) {
+	else if (ret == 0 && pf->pvar->field) {
 		ret = convert_variable_fields(vr_die, pf->pvar->var,
 					      pf->pvar->field, &pf->tvar->ref,
 					      &die_mem);



  parent reply index

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-05-28 21:44 [BUG] perf probe segfaulting when " Arnaldo Carvalho de Melo
2014-05-29  9:56 ` Masami Hiramatsu
2014-05-29 10:52 ` Masami Hiramatsu [this message]
2014-05-29 11:03   ` [PATCH -tip/urgent ] [BUGFIX] perf/probe: Fix a segfault if " Masami Hiramatsu
2014-05-29 12:19   ` [PATCH -tip ] [BUGFIX] perf/probe: Fix perf probe to find correct variable DIE Masami Hiramatsu
2014-05-29 12:39     ` Masami Hiramatsu
2014-05-29 13:41       ` Jiri Olsa
2014-06-03 18:29         ` Ingo Molnar
2014-05-29 13:56       ` Arnaldo Carvalho de Melo
2014-06-03 20:38       ` Arnaldo Carvalho de Melo
2014-06-04  8:25         ` Masami Hiramatsu
2014-06-04 11:31           ` Jiri Olsa
2014-06-04 12:19             ` Masami Hiramatsu
2014-06-04 12:22               ` Jiri Olsa
2014-06-03 18:56     ` Arnaldo Carvalho de Melo
2014-06-05  8:15     ` [tip:perf/urgent] perf probe: " tip-bot for Masami Hiramatsu
2014-05-30  6:03   ` [PATCH -tip/urgent ] [BUGFIX] perf/probe: Fix a segfault if asked for variable it doesn't find Namhyung Kim
2014-05-30  6:32     ` Masami Hiramatsu
2014-06-05  8:15   ` [tip:perf/urgent] perf probe: " tip-bot for Masami Hiramatsu

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