On 10/03/2026 23:51, Alexander Kuzmenkov wrote:
On 16/02/2026 21:10, Andres Freund wrote:
I don't think it makes a whole lot of sense to tackle this
specifically for
xl_running_xacts. Until now we just accepted that WAL insertions can
contain
random padding. If we don't want that, we should go around and make
sure that
there is no padding (or padding is initialized) for *all* WAL records,
document that as the rule, and remove the relevant valgrind suppressions.
That's not random, that's server memory, right? Probably not another
Heartbleed, but I'd rather initialize a few locals than find out.
Happy to see this being worked on, these uninitialized WAL records are a
major obstacle to enabling MemorySanitizer. I ran into this again today
and this is how I found this thread. Unfortunately the MemorySanitizer
can't even use the same suppressions as Valgrind, because the
suppression architecture is different (can only remove the checks from a
given function, not all stack traces that have this function like
Valgrind does).
+1 for initializing all padding in WAL records. In fact I thought that
we already did that. (Except in this case, apparently)
- Heikki
