[lwip-devel] [bug #21433] Calling mem_free/pbuf_free from interrupt context isn't safe

[Simon Goldschmidt]

Follow-up Comment #1, bug #21433 (project lwip):

My favourite solution for this is to create a new semaphore function
'sys_sem_tryget(sem)' which behaves much like 'sys_arch_mbox_tryfetch()'
(check if the semaphore is available, return SYS_ARCH_TIMEOUT if not; don't
block -> usable from interrupt context).

Then, if the semaphore is not available, put the struct mem on a list of
memory to free. This list is then freed both at the end of mem_free (from
application context) and at the start of mem_malloc (to make sure everything
is freed before allocating again), all the time protected by mem_sem.

Attached a patch, please comment!

The reason I'd change this fast is we could include sys_sem_tryget in 1.3.0
so most port-breaks are done now.

(file #14212)
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Additional Item Attachment:

File name: mem_free_from_interrupt.patch  Size:3 KB


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