Messages in this thread | | | Date | Sun, 24 Jun 2007 09:38:50 +0100 | From | Russell King <> | Subject | Re: Oops in a driver while using SLUB as a SLAB allocator |
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On Fri, Jun 22, 2007 at 07:39:33PM +0100, Hugh Dickins wrote: > On Fri, 22 Jun 2007, Christoph Lameter wrote: > > > > Add VM_BUG_ON in case someone uses page_mapping on a slab page > > > > Detect slab objects being passed to the page oriented functions of the VM. > > > > It is not sufficient to simply return NULL because the functions calling > > page_mapping may depend on other items of the page_struct also to be setup > > properly. Moreover the slab object may not be properly aligned. The page > > orientedfunctions of the VM expect to operate on page aligned, page sized > > objects. operations on objects straddling page boundaries may only affect > > the objects partially which may lead to surprising results. > > > > It is better to detect eventually remaining uses and eliminate them. > > > > Signed-off-by: Christoph Lameter <clameter@sgi.com> > > I'm quite happy with this approach for 2.6.23-rc, along with your ARM > dma_map patch which (if I understood aright) rmk approved.
I didn't approve it. Please re-read my reply - there are still some unanswered questions in it which _really_ need answering.
The report talks about the AT91 machines. These machines do not have cache coherent DMA. Therefore, the code being patched should be optimised away by the compiler. *Or* we have even bigger problems.
Please forward the original problem report.
-- Russell King Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/ maintainer of: - 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/
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