[PATCH 14/36] perf annotate: Fix objdump comment parsing for Intel mov dissassembly

Arnaldo Carvalho de Melo
2017-12-06T14:49:16Z

From: Thomas Richter <tmricht@linux.vnet.ibm.com>

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@linux.vnet.ibm.com>
Reviewed-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Acked-by: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Fixes: 6de783b6f50f ("perf annotate: Resolve symbols using objdump comment")
Link: http://lkml.kernel.org/r/20171128075632.72182-1-tmricht@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
tools/perf/util/annotate.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/tools/perf/util/annotate.c b/tools/perf/util/annotate.c
index 22ea7936d92f..facad1e279a8 100644
--- a/tools/perf/util/annotate.c
+++ b/tools/perf/util/annotate.c
@@ -322,6 +322,8 @@ static int comment__symbol(char *raw, char *comment, u64 *addrp, char **namep)
return 0;

*addrp = strtoull(comment, &endptr, 16);
+ if (endptr == comment)
+ return 0;
name = strchr(endptr, '<');
if (name == NULL)
return -1;
@@ -435,8 +437,8 @@ static int mov__parse(struct arch *arch, struct ins_operands *ops, struct map *m
return 0;

comment = ltrim(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;

@@ -480,7 +482,7 @@ static int dec__parse(struct arch *arch __maybe_unused, struct ins_operands *ops
return 0;

comment = ltrim(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;
}
--
2.13.6