Using version 10.0.0 of FreeRTOS I’ve been tracking down the source of a memory leak and have determined that it has something to do with using snprintf when floats are included in the argument list. I stripped down my code to this test task: void main_test_task(void *p) { size_t freeNow; uint1…

Using newlib? Which heap implementation are you using for FreeRTOS? (heap3.c?) Which tool provider? Take a look here for a relevant discussion. There may be an issue with the way your tool provider built newlib. [image] Making sure a deleted task's OS/clib resources have been …

Yes newlib, and for heap, heap_useNewlib.c IDE/Toolchain is Atmel Studio. I’ll take a look at that link, thanks.

That thread does sound an awful lot like what I’m experiencing. Shame that the root cause wasn’t uncovered though.

The issue does go away if I change #define configUSE_NEWLIB_REENTRANT from 1 to 0.

Yes, that’s the issue then. As a workaround can your design avoid deleting tasks? That way you could keep configUSE_NEWLIB_REENTRANT set to 1. Alternatively you could get support from Atmel. They probably need to change the newlib config. Or you could venture into making a newlib build for your…

I may be able to work around not deleting tasks, but that’s hardly ideal. I’ve figured out which version of newlib the pre-built library is based on, and am looking into rebuilding it, assuming I can figure out what needs to be changed. I’m actually using the nano version of newlib. Out of curiou…

I’d like to add that there are very few (legacy) non-reentrant resp. stateful libc functions like e.g. strtok where a reentrant alternative version strtok_r exists. Avoiding using those functions allows to go with configUSE_NEWLIB_REENTRANT being disabled. When in doubt the newlib sources can be ch…

[image] hillridge: I may be able to work around not deleting tasks, but that’s hardly ideal. Don’t know your application, but usually the design is better if it doesn’t include task deletion at all. Maybe that’s true in your case too? To add to Hartmut’s excellent advice, note that in the p…

It seems like I have 3 possible options to move forward: Set configUSE_NEWLIB_REENTRANT to 0 and switch to _r version of any problematic functions (if it exists) Leave configUSE_NEWLIB_REENTRANT as 1 and don’t delete/recreate threads Figure out the root cause and rebuild newlib with it fixed #1 i…

[image] hillridge: Set configUSE_NEWLIB_REENTRANT to 0 and switch to _r version of any problematic functions (if it exists) No, the _r versions in newlib are the ones causing the issue (they are automatically used internally to newlib, so you are already using them). They are safely reentran…

Thanks, I follow you now. #2 does sound like the best approach, though it would take some redesign since I have a few tasks that get spun up to do a certain action, then get deleted when they are finished. I’m going to waste the part of my day that wasn’t wasted in meetings looking into the 3rd op…

Memory Leak using snprintf with floats

Kernel

jefftenney (Jeff) August 18, 2021, 6:44pm 13

I believe so. This post indicates NXP got their newlib build configured “correctly”. But I don’t know from my own experience.

Topic		Replies	Views
Memory leak on task deletion with configUSE_NEWLIB_REENTRANT Kernel	20	2365	December 5, 2020
Making sure a deleted task's OS/clib resources have been freed Kernel	28	9378	October 14, 2021
FreeRTOS(8.0.1) + newlib from ARM GCC Kernel	4	475	November 18, 2014
sprintf %f corrupts stack Kernel	14	1161	July 2, 2017
snprintf error (PIC32MZ2048EFM064) Kernel	14	565	December 4, 2018

Memory Leak using snprintf with floats

Related topics