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Possible memory leaks when configUSE_NEWLIB_REENTRANT 1

Posted by wella on April 8, 2014


before submitting a bug I would like to discuss the following issue. I am using GNU Tools for ARM Embedded Processors with the Newlib libray. I have also enabled the configUSENEWLIBREENTRANT macro to support task concurrency. However during the task deletion (no so much realtime...) the reent xNewLibreent is simply freed with the TCB. As far as I know the reent struct should be reclaimed by calling _reclaimreent at first. However such call is missing in prvDeleteTCB( TCB_t *pxTCB ). There should be

	#if ( configUSE_NEWLIB_REENTRANT == 1 )

	#endif /* configUSE_NEWLIB_REENTRANT */

before vPortFree( pxTCB ).

This is even more critical with the Newlib compiled with REENTSMALL. There is a workaround to hook to portCLEANUPTCB( pxTCB ) but the user needs to access pxTCB directly.

Anyway thank you for supporting Newlib.

Best Martin

Possible memory leaks when configUSE_NEWLIB_REENTRANT 1

Posted by rtel on April 9, 2014

Thanks for pointing this out. Note the caveats about newlib support, in that it was added following user request, but I don't use it myself, so am reliant on other to point these things out.

Take a look at tasks.c in the head revision to see if it is correctly meeting your needs now.

[don't know why your post got put into the moderation list - I don't seem to be able to turn that feature off but very few posts get trapped there].


Possible memory leaks when configUSE_NEWLIB_REENTRANT 1

Posted by wella on April 9, 2014

Hello, thank you. It seems to be correct. However I am using newlib only 3 days so that some opinions from more skilled users than me would be valuable.

I appreciate the newlib support got into mainline. I would rather to open a discussion before first because there are some caveats I am not aware of. E.g. I read a nice article about the Newlib today and there is a suggestion:

When the thread terminates, you should clean up all stdio usage by the thread and call of its own atexit handlers by calling (see "reent.c"): wrapupreent(thread_state); source: http://andrewsterian.com/424/Lecture17.pdf

Later on,

Assuming this function has been really only introduced for RTEMS, and given that it's not used in newlib nor in RTEMS, I just removed it now, as you proposed. source: https://sourceware.org/ml/newlib/2013/msg00372.html

Best Martin

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