Messages in this thread | | | Date | Tue, 29 Mar 2005 14:18:02 -0500 | From | William Cohen <> | Subject | Re: kprobe_handler should check pre_handler function |
| |
Ananth N Mavinakayanahalli wrote: > On Mon, Mar 28, 2005 at 04:10:32PM -0500, William Cohen wrote: > > Hi Will, > > >>I found kprobes expects there to be a pre_handler function in the >>structure. I was writing a probe that only needed a post_handler >>function, no pre_handler function. The probe was tracking the >>destinations of indirect calls and jumps, the probe needs to fire after >>the instruction single steps to get the target address. The probe >>crashed the machine because arch/i386/kernel/kprobe.c:kprobe_handler() >>blindly calls p->pre_handler(). There should be a check to verify that >>the pointer is non-null. There are cases where the pre_handler is not >>needed and it would make sense to set it to NULL. Thus, a check should >>be done for pre_handler like post_handler and fault_handler. > > > You are right. The check for pre_handler is needed and here is a patch > against 2.6.12-rc1-mm3 that does this. > > Thanks, > Ananth
Ananth,
Thanks. It looks like it addresses the problem. Could you see about getting this patch in the upstream kernel?
-Will
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |