On 24 September 2013 07:23, Anurag Aggarwal <[email protected]> wrote: > While executing unwind backtrace instructions in ARM, in the function > unwind_exec_insn() > there are chances that SP overflows from stack. > > > For example while executing instruction with opcode 0xAE, vsp can go > beyond stack to area that has not been allocated till now. > > unsigned long *vsp = (unsigned long *)ctrl->vrs[SP]; > int reg; > > /* pop R4-R[4+bbb] */ > for (reg = 4; reg <= 4 + (insn & 7); reg++) > ctrl->vrs[reg] = *vsp++; > > The above scenario can happen while executing any of the unwind instruction. > > One of the ways to fix the problem is to check for vsp with stack > limits before we increment it, but doing it for all the instructions > seems a little bad. > > I just want to know that if anyone has faced the problem before
I haven't seen it but I think with some stack (or unwind bytecode) corruption it could happen. I think we could place some checks only when vsp is assigned and return -URC_FAILURE, together with some warning. -- Catalin -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
