Question

Can someone please help me with interpreatation of this stack trace:

        Loading modules: [ libumem.so.1 libc.so.1 libuutil.so.1 ld.so.1 ]
        > $c
        libc.so.1`strlen+0xc(80b37ba, fe679d2c, fe679d00, 0)
        libc.so.1`snprintf+0x74(fe67d970, 1388, 80b37b8, efef9f68, 80b379d, fe679e30)
        > 80b37ba::whatis
        80b37ba is unknown
        > fe679d2c::whatis
        fe679d2c is unknown
        > fe679d00::whatis
        fe679d00 is unknown

strlen function gets one argument, but in this stack trace I see 3 addresses ? What is the meaning of them ?

regards

Answer 1

The debugger doesn’t manage to interpret most of it.

The debugger may not know how many parameters a function gets. So it prints more. But you can ignore the extra parameters.

The parts that do make sense show that snprintf was called, and then call strlen. This is probably due to %s in the format string. The strlen parameter is similar (not identical, I don’t know why), to snprintf‘s 3rd parameter.
So probably some code does something like snprintf("%d %s\n", number, string).
You can find the actual format string at fe67d970, and it will probably let you identify who called it (unless you use the same format string everywhere).