Re: [PATCH 3/5] uprobes: remove check for uprobe variable in handle_swbp()

[Sebastian Andrzej Siewior]

On 08/08/2012 11:10 AM, Suzuki K. Poulose wrote:
> > --- a/kernel/events/uprobes.c
> > +++ b/kernel/events/uprobes.c
> > @@ -1528,17 +1528,15 @@ cleanup_ret:
> > utask->active_uprobe = NULL;
> > utask->state = UTASK_RUNNING;
> > }
> > - if (uprobe) {
> > - if (!(uprobe->flags & UPROBE_SKIP_SSTEP))
> > + if (!(uprobe->flags & UPROBE_SKIP_SSTEP))
> Shouldn't we check uprobe != NULL before we check the uprobe->flags ?
> i.e, shouldn't the above line be :
>
> if (uprobe && ! (uprobe->flags & UPROBE_SKIP_SSTEP)) ?

The function starts like this:

         if (!uprobe) {
                 if (is_swbp > 0) {
                         send_sig(SIGTRAP, current, 0);
                 } else {
                         instruction_pointer_set(regs, bp_vaddr);
                 }
                 return;
         }

Which makes uprobe != NULL by the time we get there, no?

Sebastian
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