Several things to consider,
a) Conditional on an uninitialized variable. When this happens in a
system library it's invariably something we can't control. Rarely, we
found, it's uninitialized input to the library API. We can look at these
but likely we won't find anything. Most of these are due to using
particular instructions that don't initialize all the bytes in a word that
is later fetched (e.g. a single bit) that causes the false positive.
b) Access to unitialized memory. This also happens frequently in
optimized code when the code uses SSE instruction (e.g. strcmp, strncmp,
strcpy, etc are common culprits). This is a known problem with valgrind.
c) The server does allocate memory that will never be freed as it's
permanently needed to hold various information. Sometimes Valgrind looses
track that it's still accessible and reports it as likely or definitely
lost. In fact, it's not. The key here is when the memory area is involved
in anything method that has "config" in it.
Hope that explains the source of many of the false reports.
Andy
On Thu, 11 Mar 2021, Oliver Freyermuth wrote:
> Sadly, the initial conditional jump is missing from the new full log.
> Also, that seems to be an older XRootD 4 version, so some of these may already have been addressed.
>
> The first one likely comes from here, or an earlier variant of that code:
> https://github.com/xrootd/xrootd/blob/61b1e815cb683eb420ad02d7cef17851584797f3/src/XrdNet/XrdNetUtils.cc#L363-L367
> but I do not detect the logic error there...
>
> I think the last "possibly lost" is not a real issue, it is happening inside `ld` by library loading.
>
> But I'll leave a better diagnosis to the XRootD devs :-).
>
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