Strange issue with mutex

[Korken]

Hi all,

I have been adding mutexes to a piece of code, but I always get the following error when I have debug checks enabled:

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#0  chSysHalt (reason=reason@entry=0x800e5cc <func.7893> "chSchReadyI") at ../../src/ChibiOS/os/rt/src/chsys.c:207
#1  0x0800189a in chSchReadyI (tp=0x200056ac <mac_arbiter_+860>) at ../../src/ChibiOS/os/rt/src/chschd.c:223
#2  0x08002340 in chMtxUnlock (mp=mp@entry=0x20003edc <cmd_thd+2428>) at ../../src/ChibiOS/os/rt/src/chmtx.c:383

which happens in the following code:

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void send(uint64_t address, msg_t* msg, bool ack)
{
    _mtx.lock();
    _mac.send(address, msg, ack); // Something that needs protection
    _mtx.unlock();
   
    signalEvents(1); // Wakeup the MAC data pump
}

Is there something obvious that I am missing here in the use of my mutex?
send is being called inside a thread, and _mtx is part of a class.
Using ChibiOS 17.6.x.

Thanks!

[Giovanni]

Hi,

Most likely the problem is not in that code, it is about the unlocked thread already being in the READY or FINAL state. Maybe you have a thread terminating before releasing its mutexes or do something strange from an ISR.

Giovanni

[Korken]

Thanks Giovanni!

Perfect analysis as always