https://devzone.nordicsemi.com/f/nordic-q-a/51034/safe-a-sync-socket-operationsHi, I was wondering if I could get some guidance (or directed to some documentation on the subject) with regards to what socket operations are safe to do in a-sync timer callback. Right now I am trying the following: I setup a UDP socket listeneren-USTelligent Community 13Fri, 16 Aug 2019 11:39:37 GMThttps://devzone.nordicsemi.com/thread/204484?ContentTypeID=1Fri, 16 Aug 2019 11:39:37 GMT137ad170-7792-4731-bb38-c0d22fbe4515:d913e17d-5269-4175-837b-5872a950be0cH&#229;kon Alseth<p>Hi,</p> <p>&nbsp;</p> [quote user=""]If I try and do step 3 asynchronously, within the timer handler, it fails.[/quote] <p>K_TIMER, right? Those will execute in interrupt context, so I would not recommend&nbsp;calling functions directly from the k_timer_handler, as some functions (like taking a semaphore) will generate a fault condition if called from interrupt context, but instead use a work queue (<a href="https://docs.zephyrproject.org/1.9.0/kernel/threads/workqueues.html">https://docs.zephyrproject.org/1.9.0/kernel/threads/workqueues.html</a>)</p> <p>This would be similar in behavior as your current workaround (setting a flag).</p> <p>&nbsp;</p> <p>Kind regards,</p> <p>Håkon</p><div style="clear:both;"></div>