On 11/6/18 6:51 PM, Tomas Vondra wrote:
> On 11/6/18 6:35 PM, Alvaro Herrera wrote:
>> On 2018-Nov-06, Tomas Vondra wrote:
>>
>>> Hi,
>>>
>>> I've recently updated to Fedora 28, and in that environment I get
>>> quite a
>>> few new valgrind issues (see the attached log).
>>
>> Hmm, related to
>> https://postgr.es/m/20180220150838.GD18315@e733.localdomain ?
>> Apparently the right answer is to add local suppressions ...
>>
>
> Yep, seems like that. I'll check if the patch proposed by Aleksander
> resolves all the issues reported by valgrind.
>
OK, I propose we add suppressions per the attached patch.
The rules are clearly incomplete, due to dependence on optimization
used. For example now the stack includes __wcsnlen_avx2, but I see it
was __wcsnlen_sse4_1 in Aleksander's report in February.
Not sure what to do about this - maybe we should wildcard this first
frame, to accept all wcsnlen variants. Opinions?
regards
--
Tomas Vondra http://www.2ndQuadrant.com
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
diff --git a/src/tools/valgrind.supp b/src/tools/valgrind.supp
index 2f3b602773..1c8311338c 100644
--- a/src/tools/valgrind.supp
+++ b/src/tools/valgrind.supp
@@ -213,3 +213,39 @@
Memcheck:Cond
fun:PyObject_Realloc
}
+
+# wcsrtombs uses some clever optimizations internally, which to valgrind
+# may look like access to uninitialized data. For example AVX2 instructions
+# load data in 256-bit chunks, irrespectedly of wchar length. gconv does
+# somethink similar by loading data in 32bit chunks and then shifting the
+# data internally. Neither of those actually uses the uninitialized part
+# of the buffer, as far as we know.
+#
+# https://www.postgresql.org/message-id/90ac0452-e907-e7a4-b3c8-15bd33780...@2ndquadrant.com
+
+{
+ wcsnlen_optimized
+ Memcheck:Cond
+ fun:__wcsnlen_avx2
+ fun:wcsrtombs
+ fun:wcstombs
+ fun:wchar2char
+}
+
+{
+ wcsnlen_optimized_addr32
+ Memcheck:Addr32
+ fun:__wcsnlen_avx2
+ fun:wcsrtombs
+ fun:wcstombs
+ fun:wchar2char
+}
+
+{
+ gconv_transform_internal
+ Memcheck:Cond
+ fun:__gconv_transform_internal_utf8
+ fun:wcsrtombs
+ fun:wcstombs
+ fun:wchar2char
+}
