From: Ian Rogers <irog...@google.com>
Realloc of size zero is a free not an error, avoid this causing a double
free. Caught by clang's address sanitizer:
==2634==ERROR: AddressSanitizer: attempting double-free on 0x6020000015f0 in
thread T0:
#0 0x5649659297fd in free
llvm/llvm-project/compiler-rt/lib/asan/asan_malloc_linux.cpp:123:3
#1 0x5649659e9251 in __zfree tools/lib/zalloc.c:13:2
#2 0x564965c0f92c in mem2node__exit tools/perf/util/mem2node.c:114:2
#3 0x564965a08b4c in perf_c2c__report tools/perf/builtin-c2c.c:2867:2
#4 0x564965a0616a in cmd_c2c tools/perf/builtin-c2c.c:2989:10
#5 0x564965944348 in run_builtin tools/perf/perf.c:312:11
#6 0x564965943235 in handle_internal_command tools/perf/perf.c:364:8
#7 0x5649659440c4 in run_argv tools/perf/perf.c:408:2
#8 0x564965942e41 in main tools/perf/perf.c:538:3
0x6020000015f0 is located 0 bytes inside of 1-byte region
[0x6020000015f0,0x6020000015f1)
freed by thread T0 here:
#0 0x564965929da3 in realloc
third_party/llvm/llvm-project/compiler-rt/lib/asan/asan_malloc_linux.cpp:164:3
#1 0x564965c0f55e in mem2node__init tools/perf/util/mem2node.c:97:16
#2 0x564965a08956 in perf_c2c__report tools/perf/builtin-c2c.c:2803:8
#3 0x564965a0616a in cmd_c2c tools/perf/builtin-c2c.c:2989:10
#4 0x564965944348 in run_builtin tools/perf/perf.c:312:11
#5 0x564965943235 in handle_internal_command tools/perf/perf.c:364:8
#6 0x5649659440c4 in run_argv tools/perf/perf.c:408:2
#7 0x564965942e41 in main tools/perf/perf.c:538:3
previously allocated by thread T0 here:
#0 0x564965929c42 in calloc
third_party/llvm/llvm-project/compiler-rt/lib/asan/asan_malloc_linux.cpp:154:3
#1 0x5649659e9220 in zalloc tools/lib/zalloc.c:8:9
#2 0x564965c0f32d in mem2node__init tools/perf/util/mem2node.c:61:12
#3 0x564965a08956 in perf_c2c__report tools/perf/builtin-c2c.c:2803:8
#4 0x564965a0616a in cmd_c2c tools/perf/builtin-c2c.c:2989:10
#5 0x564965944348 in run_builtin tools/perf/perf.c:312:11
#6 0x564965943235 in handle_internal_command tools/perf/perf.c:364:8
#7 0x5649659440c4 in run_argv tools/perf/perf.c:408:2
#8 0x564965942e41 in main tools/perf/perf.c:538:3
v2: add a WARN_ON_ONCE when the free condition arises.
Signed-off-by: Ian Rogers <irog...@google.com>
Acked-by: Jiri Olsa <jo...@redhat.com>
Cc: Alexander Shishkin <alexander.shish...@linux.intel.com>
Cc: Mark Rutland <mark.rutl...@arm.com>
Cc: Namhyung Kim <namhy...@kernel.org>
Cc: Peter Zijlstra <pet...@infradead.org>
Cc: Stephane Eranian <eran...@google.com>
Cc: clang-built-li...@googlegroups.com
Link: http://lore.kernel.org/lkml/20200320182347.87675-1-irog...@google.com
Signed-off-by: Arnaldo Carvalho de Melo <a...@redhat.com>
---
tools/perf/util/mem2node.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/tools/perf/util/mem2node.c b/tools/perf/util/mem2node.c
index 797d86a1ab09..c84f5841c7ab 100644
--- a/tools/perf/util/mem2node.c
+++ b/tools/perf/util/mem2node.c
@@ -1,5 +1,6 @@
#include <errno.h>
#include <inttypes.h>
+#include <asm/bug.h>
#include <linux/bitmap.h>
#include <linux/kernel.h>
#include <linux/zalloc.h>
@@ -95,7 +96,7 @@ int mem2node__init(struct mem2node *map, struct perf_env *env)
/* Cut unused entries, due to merging. */
tmp_entries = realloc(entries, sizeof(*entries) * j);
- if (tmp_entries)
+ if (tmp_entries || WARN_ON_ONCE(j == 0))
entries = tmp_entries;
for (i = 0; i < j; i++) {
--
2.21.1
