On 5 December 2014 at 17:27, Russell King - ARM Linux <linux@xxxxxxxxxxxxxxxx> wrote: > On Fri, Dec 05, 2014 at 05:07:45PM +0000, Catalin Marinas wrote: >> On Fri, Dec 05, 2014 at 12:05:06PM +0000, Will Deacon wrote: >> > Care to submit this as a proper patch? We should at least fix Peter's issue >> > before doing things like extending headers, which won't work for older >> > kernels anyway. >> >> Quick fix is the revert of the whole patch, together with removing >> PAGE_ALIGN(end) in poison_init_mem() on arm32. If Russell is ok with >> this patch, we can take it via the arm64 tree, otherwise I'll send you a >> partial revert only for the arm64 part. > > Not really. Let's look at the history. > > For years, we've been poisoning memory, page aligning the end pointer. > This has never been an issue. Depends what you mean by "never been an issue". I had to change QEMU (commit 98ed805c, January 2013) for 32-bit ARM back when the kernel started trashing the tail end of the page after the initrd with the poisoning, to 4K-align the dtb so it didn't share a page with the initrd-tail. That nobody else complained suggests that most bootloaders don't in practice overlap the two, though (ie that QEMU is an outlier in how it chooses to arrange things in memory). I should probably have reported the breakage at the time, but I took the pragmatic (lazy?) approach of just changing our bootloader code. thanks -- PMM -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>