[PATCH] perf annotate: Fix SEGV with assembly labels

[Anton Blanchard <anton@samba.org>]

I'm getting a SEGV when running perf annotate on a ppc64 box. The
objdump -S output causing the SEGV looks like:

        b       .ret_from_except_lite
c00000000000a508:       b       c00000000000a4d4 <.ret_from_except_lite>

1:      bl      .save_nvgprs
c00000000000a50c:       bl      c00000000000a110 <.save_nvgprs>

symbol__parse_objdump_line makes an effort to distinguish between
instruction addresses and assembly labels but the check is
insufficent.

In the above case we get line_ip = 1, and (line_ip - start) is
positive so our offset < 0 check does not catch it.

Fix this by adding an unsigned comparison against start.

Signed-off-by: Anton Blanchard <anton@samba.org>
Cc: <stable@kernel.org>
---

diff --git a/tools/perf/util/annotate.c b/tools/perf/util/annotate.c
index d102716..a791d23 100644
--- a/tools/perf/util/annotate.c
+++ b/tools/perf/util/annotate.c
@@ -809,7 +809,7 @@ static int symbol__parse_objdump_line(struct symbol *sym, struct map *map,
 		    end = map__rip_2objdump(map, sym->end);
 
 		offset = line_ip - start;
-		if (offset < 0 || (u64)line_ip > end)
+		if (offset < 0 || (u64)line_ip < start || (u64)line_ip > end)
 			offset = -1;
 		else
 			parsed_line = tmp2 + 1;