[cairo] Pixman concurrency problem on iOS/ARM

[Siarhei Siamashka]

On Mon, Mar 26, 2012 at 10:42 PM, cu <cairouser at yahoo.com> wrote:
> I seem to be hitting occasional (but unfortunate) issue where Pixman
> crashes when the same function is called from two threads.
> During that time nothing is in common between threads - i.e. they render
> from/to separate surfaces, cairo drawing contexts etc.
>
> Nevertheless, from time to time when two threads enter
> pixman_composite_over_8888_8888_asm_neon, the process will crash.
> I am using pixman 0.24.4 for iOS compiled with the "one off" set of
> generated asm NEON intrinsics.
>
> Any help from those "in the know" would be greatly appreciated.

It would help if you could reduce the testcase to a small program
which can still reproduce the problem reliably. And try whatever
debugging tools are available on iOS to get the exact address of the
crash, stack backtrace, disassembly listing and the values in
registers at the time of the crash. The more information, the better.

This could be just anything ranging from a slight ABI incompatibility
to bugs in OS kernel or hardware errata. It's hard to make any guesses
without additional information.

-- 
Best regards,
Siarhei Siamashka