在 2016/6/23 10:02, Wangnan (F) 写道:
Hi,
This patch fixes a real crash problem when we do 'perf report'
on an arm64 platform with arm32 program.
It is introduced by commit f9b2bdf228 ("perf tools: Find vdso
with the consider of cross-platform"). From dmesg report, perf
crashes in dso__type() because dso is NULL.
Still don't know why on x86 it never crash, but it is obviously
This is because the fault only occured while
dso_type==DSO__TYPE_32BIT, run 64bit executable won't enter the
fault branch, but if we run a 32bit executable on x86_64, this
bug can be reproduced easily.
# file ~/hello
~/hello: ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV),
dynamically linked (uses shared libs), for GNU/Linux 4.5.0, not stripped
# perf record -g hello
Segmentation fault
Thank you.
that we need to check the return vaule from __dso__find(): it can
be NULL.
So please consider pulling.
Thank you.
On 2016/6/22 14:57, He Kuang wrote:
We should check if 'dso' is a null pointer before passing it to the
function dso__type(), otherwise a segfault will be raised in
dso__data_get_fd(). In function machine__find_vdso(), the return value
checking of 'dso' is missed and this patch fixes this issue.
Signed-off-by: He Kuang <heku...@huawei.com>
---
tools/perf/util/vdso.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools/perf/util/vdso.c b/tools/perf/util/vdso.c
index 8f81c41..7bdcad4 100644
--- a/tools/perf/util/vdso.c
+++ b/tools/perf/util/vdso.c
@@ -296,7 +296,7 @@ static struct dso *machine__find_vdso(struct
machine *machine,
if (!dso) {
dso = __dsos__find(&machine->dsos, DSO__NAME_VDSO,
true);
- if (dso_type != dso__type(dso, machine))
+ if (dso && dso_type != dso__type(dso, machine))
dso = NULL;
}
break;
