Debugging SIGBUS on x86 Linux

You can get a SIGBUS from an unaligned access if you turn on the unaligned access trap, but normally that's off on an x86. You can also get it from accessing a memory mapped device if there's an error of some kind.

Your best bet is using a debugger to identify the faulting instruction (SIGBUS is synchronous), and trying to see what it was trying to do.

SIGBUS can happen in Linux for quite a few reasons other than memory alignment faults - for example, if you attempt to access an mmap region beyond the end of the mapped file.

Are you using anything like mmap, shared memory regions, or similar?