Messages in this thread Patch in this message |  | | | Date | Thu, 4 Jun 2009 12:26:03 +0800 | | From | Wu Fengguang <> | | Subject | Re: [PATCH] [6/16] HWPOISON: Add various poison checks in mm/memory.c |
| |
On Thu, Jun 04, 2009 at 02:46:38AM +0800, Andi Kleen wrote: > > Bail out early when hardware poisoned pages are found in page fault handling.
I suspect this patch is also not absolutely necessary: the poisoned page will normally have been isolated already.
> Since they are poisoned they should not be mapped freshly into processes, > because that would cause another (potentially deadly) machine check > > This is generally handled in the same way as OOM, just a different > error code is returned to the architecture code. > > Signed-off-by: Andi Kleen <ak@linux.intel.com> > > --- > mm/memory.c | 3 +++ > 1 file changed, 3 insertions(+) > > Index: linux/mm/memory.c > =================================================================== > --- linux.orig/mm/memory.c 2009-06-03 19:36:23.000000000 +0200 > +++ linux/mm/memory.c 2009-06-03 19:36:23.000000000 +0200 > @@ -2797,6 +2797,9 @@ > if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE))) > return ret; > > + if (unlikely(PageHWPoison(vmf.page))) > + return VM_FAULT_HWPOISON; > +
Direct return with locked page could lockup someone later. Either drop this patch or fix it with this check?
Thanks, Fengguang --- --- linux.orig/mm/memory.c +++ linux/mm/memory.c @@ -2658,8 +2658,11 @@ static int __do_fault(struct mm_struct * if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE))) return ret; - if (unlikely(PageHWPoison(vmf.page))) + if (unlikely(PageHWPoison(vmf.page))) { + if (ret & VM_FAULT_LOCKED) + unlock_page(vmf.page); return VM_FAULT_HWPOISON; + } /* * For consistency in subsequent calls, make the faulted page always
|  |