[PATCH AUTOSEL 4.18 6/8] perf report: Don't try to map ip to invalid map

Sasha Levin
2018-10-25T14:10:45Z

From: Milian Wolff <milian.wolff@kdab.com>

[ Upstream commit ff4ce2885af8f9e8e99864d78dbeb4673f089c76 ]

Fixes a crash when the report encounters an address that could not be
associated with an mmaped region:

#0 0x00005555557bdc4a in callchain_srcline (ip=<error reading variable: Cannot access memory at address 0x38>, sym=0x0, map=0x0) at util/machine.c:2329
#1 unwind_entry (entry=entry@entry=0x7fffffff9180, arg=arg@entry=0x7ffff5642498) at util/machine.c:2329
#2 0x00005555558370af in entry (arg=0x7ffff5642498, cb=0x5555557bdb50 <unwind_entry>, thread=<optimized out>, ip=18446744073709551615) at util/unwind-libunwind-local.c:586
#3 get_entries (ui=ui@entry=0x7fffffff9620, cb=0x5555557bdb50 <unwind_entry>, arg=0x7ffff5642498, max_stack=<optimized out>) at util/unwind-libunwind-local.c:703
#4 0x0000555555837192 in _unwind__get_entries (cb=<optimized out>, arg=<optimized out>, thread=<optimized out>, data=<optimized out>, max_stack=<optimized out>) at util/unwind-libunwind-local.c:725
#5 0x00005555557c310f in thread__resolve_callchain_unwind (max_stack=127, sample=0x7fffffff9830, evsel=0x555555c7b3b0, cursor=0x7ffff5642498, thread=0x555555c7f6f0) at util/machine.c:2351
#6 thread__resolve_callchain (thread=0x555555c7f6f0, cursor=0x7ffff5642498, evsel=0x555555c7b3b0, sample=0x7fffffff9830, parent=0x7fffffff97b8, root_al=0x7fffffff9750, max_stack=127) at util/machine.c:2378
#7 0x00005555557ba4ee in sample__resolve_callchain (sample=<optimized out>, cursor=<optimized out>, parent=parent@entry=0x7fffffff97b8, evsel=<optimized out>, al=al@entry=0x7fffffff9750,
max_stack=<optimized out>) at util/callchain.c:1085

Signed-off-by: Milian Wolff <milian.wolff@kdab.com>
Tested-by: Sandipan Das <sandipan@linux.ibm.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Jin Yao <yao.jin@linux.intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Fixes: 2a9d5050dc84 ("perf script: Show correct offsets for DWARF-based unwinding")
Link: http://lkml.kernel.org/r/20180926135207.30263-1-milian.wolff@kdab.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
tools/perf/util/machine.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
index 22dbb6612b41..d49744dc46d7 100644
--- a/tools/perf/util/machine.c
+++ b/tools/perf/util/machine.c
@@ -2272,7 +2272,7 @@ static int unwind_entry(struct unwind_entry *entry, void *arg)
{
struct callchain_cursor *cursor = arg;
const char *srcline = NULL;
- u64 addr;
+ u64 addr = entry->ip;

if (symbol_conf.hide_unresolved && entry->sym == NULL)
return 0;
@@ -2284,7 +2284,8 @@ static int unwind_entry(struct unwind_entry *entry, void *arg)
* Convert entry->ip from a virtual address to an offset in
* its corresponding binary.
*/
- addr = map__map_ip(entry->map, entry->ip);
+ if (entry->map)
+ addr = map__map_ip(entry->map, entry->ip);

srcline = callchain_srcline(entry->map, entry->sym, addr);
return callchain_cursor_append(cursor, entry->ip,
--
2.17.1