Re: [rvm-research] Memory Leaks in Thread Creation/Deletion

Hi,

On 05.09.2014 16:18, Carl Ritson wrote:
> For debugging I recently wrote a test that endless creates and
> terminates threads (attached as ThreadTest3.java).  This test
> consistently crashes JikesRVM after about 450,000 threads have been
> created.  The crash occurs when pthread_create fails due to a lack of
> resources, or as it turns out, a lack of memory.
I can reproduce the crash on hg tip.

> Digging around in sys.C it seems some allocation is done with C++
> primitives (new/delete) and the rest with malloc/free.  There doesn't
> appear to be an obvious reason for this.
> There also seem to be two distinct memory leaks:
>  1. the memory allocated for the parameters passed to the new thread
> via pthread_create is not freed.
>  2. the signal handling stack can be allocated twice, once by
> sysThreadStartup and once by sysSetupHardwareTrapHandler; however,
> only the stack allocated by sysThreadStartup will be release when a
> thread terminates.
> 
> Attached is a patch which attempts to address these issues with
> (mostly) minimal changes:
>  A. uses of new/delete are replaced with malloc/free.
>  B. all calls to malloc/free pass via (existing) checking functions to
> check for address space overlaps.
>  C. thread parameters are releases at thread termination.
>  D. thread termination checks for the presence of an alternate signal
> stack and release it if present.
The patch looks ok to me at first glance. If you're satisfied with your changes, I could commit them once you provide a contributor statement.


Kind regards,

Erik Brangs

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