[PATCH 3.16 073/410] perf annotate: Fix objdump comment parsing for Intel mov dissassembly

[Ben Hutchings]

3.16.57-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Thomas Richter <tmricht@xxxxxxxxxxxxxxxxxx>

commit 35a8a148d8c1ee9e5ae18f9565a880490f816f89 upstream.

The command 'perf annotate' parses the output of objdump and also
investigates the comments produced by objdump. For example the
output of objdump produces (on x86):

23eee:  4c 8b 3d 13 01 21 00 mov 0x210113(%rip),%r15
                                # 234008 <stderr@@GLIBC_2.2.5+0x9a8>

and the function mov__parse() is called to investigate the complete
line. Mov__parse() breaks this line into several parts and finally
calls function comment__symbol() to parse the data after the comment
character '#'. Comment__symbol() expects a hexadecimal address followed
by a symbol in '<' and '>' brackets.

However the 2nd parameter given to function comment__symbol()
always points to the comment character '#'. The address parsing
always returns 0 because the character '#' is not a digit and
strtoull() fails without being noticed.

Fix this by advancing the second parameter to function comment__symbol()
by one byte before invocation and add an error check after strtoull()
has been called.

Signed-off-by: Thomas Richter <tmricht@xxxxxxxxxxxxxxxxxx>
Reviewed-by: Hendrik Brueckner <brueckner@xxxxxxxxxxxxxxxxxx>
Acked-by: Ravi Bangoria <ravi.bangoria@xxxxxxxxxxxxxxxxxx>
Cc: Heiko Carstens <heiko.carstens@xxxxxxxxxx>
Cc: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
Fixes: 6de783b6f50f ("perf annotate: Resolve symbols using objdump comment")
Link: http://lkml.kernel.org/r/20171128075632.72182-1-tmricht@xxxxxxxxxxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
 tools/perf/util/annotate.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

--- a/tools/perf/util/annotate.c
+++ b/tools/perf/util/annotate.c
@@ -146,6 +146,8 @@ static int comment__symbol(char *raw, ch
 		return 0;
 
 	*addrp = strtoull(comment, &endptr, 16);
+	if (endptr == comment)
+		return 0;
 	name = strchr(endptr, '<');
 	if (name == NULL)
 		return -1;
@@ -251,8 +253,8 @@ static int mov__parse(struct ins_operand
 	while (comment[0] != '\0' && isspace(comment[0]))
 		++comment;
 
-	comment__symbol(ops->source.raw, comment, &ops->source.addr, &ops->source.name);
-	comment__symbol(ops->target.raw, comment, &ops->target.addr, &ops->target.name);
+	comment__symbol(ops->source.raw, comment + 1, &ops->source.addr, &ops->source.name);
+	comment__symbol(ops->target.raw, comment + 1, &ops->target.addr, &ops->target.name);
 
 	return 0;
 
@@ -298,7 +300,7 @@ static int dec__parse(struct ins_operand
 	while (comment[0] != '\0' && isspace(comment[0]))
 		++comment;
 
-	comment__symbol(ops->target.raw, comment, &ops->target.addr, &ops->target.name);
+	comment__symbol(ops->target.raw, comment + 1, &ops->target.addr, &ops->target.name);
 
 	return 0;
 }