ESP32 Forum

Before I start the topic let me give brief summary of the setup;

I am using esp-idf 5.2.1 version and esp32 based board. My project contains WiFi connection as wifi_sta and creating a socket connection with a remote ip and port in order to exchange data.

Basically I have this core dump which I am having difficulties to figure out what is causing the crash resulting the core dump.
In the core dump, the back trace leads me through a line in my code which is an if statement where as in the statement comparing one defined constant and one constant integer. Other than that i see no useful information in the core dump. Here is my core dump and the line of code which it refers to:


The line refered as "0x400e0f3f: ReadArea at D:/Github/KRIO-2S_V5/main/s7.c:323" is as follows :


WordLen is a function parameter with type int and S7WLBit is #defined as 0x01 of value. The function is called at "0x400e1a5e: GetDInt_S7 at D:/Github/KRIO-2S_V5/main/s7.c:970" with the WordLen as a #defined value of 0x02. So basically my core dump lead me with the following code:


And boom! I have a crash

I am trying to receive a better information according of this crash by looking at the core dump but i can not tell more.

Any help on this topic?

Hard to say without the sources; in general it could be that your C code gets optimized in such a way that bits of the preceding or following lines are merged with that statement.

Thanks for the reply!

For further clarification, here is the follow and previous lines of the referenced line in the core dump.

I hope that brings some color to the picture.

Any chance that `info` is a null pointer or something? You can probably try loading the coredump into gdb, that might allow you to print its value.

"info" is pointer which in the program, it is used by multiple tasks and is thread safe as it is used with a mutex. When the count of tasks which are using "info" are zero than there is another routine frees that pointer which also waiting for the mutex indefinetely to free.

In this sense I've double checked the possibilities to share common resource within tasks and it is free routine and everything seems correct.

About the second recommendation to load the core dump into gdb, can you broaden this subject? I am not sure what is referred as gdb at this point.

Note that 'info' doesn't need to be explicitly set to NULL in order for it to be NULL. E.g. something like a buffer overflow or an use-after-free could also have overwritten the memory where that pointer is stored.

Not sure what IDE you're using, but commandline you could try this. You should be able to do a 'p info' to get the value of that pointer.

After some deep code review I found out the problem was the pointer info being nulled during a socket close operation.

I have a end point struct which holds the socket and info pointer and my socket routine basically closes socket and frees info when it detects there is a socket operation error. Hence I found out this by testing a multi thread sharing same socket as they had a synchronization issue while rising the socket error and resulting in closing a on use socket for another thread.

Thanks for the replies