Re: Debugging 64-bit kernel crashes involving

On 3/8/07, Kyle McMartin <[email protected]> wrote:
> On Tue, Feb 27, 2007 at 06:02:10PM -0600, James Bottomley wrote:
> > +     /* need to be executing in user context */
> > +     if (regs->iasq[0] != 0 || regs->iasq[1] != 0) {
>
> Is there a reason we can't use user_space() from ptrace.h here? You may have
> just spotted a subtle bug elsewhere since user_space only checks iasq[1]...
>

I would have checked both for the sake of consistency.

Upon entry to the syscall both iasq[0] and iasq[1] will be user
spaces, so only checking iasq[1] is OK. In the case of interruption it
would only matter if iasq[0]==user, and iasq[1]!=user, but this would
mean we interrupted the kernel on a return to userspace. If such a
thing can happen, then yes, we should probably check both in
"user_space()" and add comments.

I haven't thought very hard about this, so ICBW.

Are we considering James' patch for inclusion into git.parisc-linux.org?

Cheers,
Carlos.