Re: [openib-general] Re: [PATCH][RFC][0/4] InfiniBand userspace verbs implementation

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 

On 4/26/05, Andrew Morton <[email protected]> wrote:

> >
> > However I don't see how to make it work if I put the reference
> > counting for overlapping regions in userspace but when I want mlock()
> > accounting in the kernel.  If a buggy/malicious app does:
> >
> >     a) register from 0x0000 to 0x2fff
> >     b) register from 0x1000 to 0x1fff
> >     c) unregister from 0x0000 to 0x2fff
> 
> As far as the kernel is concerned, step b) should be a no-op.  (The kernel
> might choose to split the vma, but that's not significant).
> 

If "register" and "unregister" is meant in the RDMA sense then the above
sequence is totally reasonable. The b) registration could be for a different
protection domain that did not require access to all of the larger region.

Unless a full counting lock is available from the kernel, the responsibility
of the collective RDMA components would be to a) pin 0x0000 to 0x2fff,
b) nothing c) unpin 0x000 to 0x0fff and 0x2000 to 0x2fff
-
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/
[Index of Archives]     [Kernel Newbies]     [Netfilter]     [Bugtraq]     [Photo]     [Stuff]     [Gimp]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Video 4 Linux]     [Linux for the blind]     [Linux Resources]
  Powered by Linux