On Wed, 13 Feb 2013 11:39:29 +0000 Catalin Marinas <catalin.marinas@xxxxxxx> wrote: > ARM processors with LPAE enabled use 3 levels of page tables, with an > entry in the top level (pgd) covering 1GB of virtual space. Because of > the branch relocation limitations on ARM, the loadable modules are > mapped 16MB below PAGE_OFFSET, making the corresponding 1GB pgd shared > between kernel modules and user space. > > Since free_pgtables() is called with ceiling == 0, free_pgd_range() (and > subsequently called functions) also frees the page table > shared between user space and kernel modules (which is normally handled > by the ARM-specific pgd_free() function). > > This patch changes the ceiling argument to mm->task_size for the > free_pgtables() and free_pgd_range() function calls. We cannot use > TASK_SIZE since this macro may not be a run-time constant on 64-bit > systems supporting compat applications. I'm trying to work out why we're using 0 in there at all, rather than ->task_size. But that's lost in the mists of time. As you've discovered, handling of task_size and TASK_SIZE is somewhat inconsistent across architectures and with compat tasks. I guess we toss it in there and see if anything breaks... -- 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>