On 07/02/2021 14:45, Jonas Maebe via fpc-devel wrote:
On 02/02/2021 16:48, C Western via fpc-devel wrote:
My application works fine single threaded, but crashes occasionally when
multi threaded, with what I think is some sort of memory corruption, but
I haven't been able to pin this down yet, and fixing the above two
points would help.
It's probably a data race. AArch64's memory model is much more relaxed
than that of x86-64, so data races are much more likely to lead to
errors. Additionally, while on x86 interlocked* routines implicitly act
as memory barriers between them (due to an architectural idiosyncrasy),
they don't on any other architecture.
I have located a possible fix; however I don't understand why I need to
make the change I did. The variable reads/writes of concern currently
use SetEvent in one thread and WaitFor in another - do these not have
implicit memory barriers in them? Or is an explicit memory barrier
required in AArch64? (or it could also be a different issue).
Colin
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