On Fri, 21 Nov 2008 15:16:50 +0100 Helge Deller <deller@xxxxxx> wrote: > Any user on existing parisc 32- and 64bit-kernels can easily crash > the kernel and as such enforce a DSO. > A simple testcase is available here: > http://gsyprf10.external.hp.com/~deller/crash.tgz > > The problem is introduced by the fact, that the handle_interruption() > crash handler calls the show_regs() function, which in turn tries > to unwind the stack by calling parisc_show_stack(). > Since the stack contains userspace addresses, a try to unwind > the stack is dangerous and useless and leads to the crash. > > The fix is trivial: For userspace processes > a) avoid to unwind the stack, and > b) avoid to resolve userspace addresses to kernel symbol names. > > While touching this code, I converted print_symbol() to %pS > printk formats and made parisc_show_stack() static. > > An initial patch for this was written by Kyle McMartin back in August: > http://marc.info/?l=linux-parisc&m=121805168830283&w=2 > > Compile and run-tested with a 64bit parisc kernel. Why has a fix for such a severe bug been floating around unmerged for such a long time? > Patches for -stable series will follow shortly. That shouldn't be needed - I'll cc stable on my copy and the stable maintainers should see that and pick it up. The patch applies cleanly all the way back to 2.6.25. -- To unsubscribe from this list: send the line "unsubscribe linux-parisc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
