From: Joonsoo Kim <[email protected]> We can disable debug_pagealloc processing even if the code is compiled with CONFIG_DEBUG_PAGEALLOC. This patch changes the code to query whether it is enabled or not in runtime.
v2: update comment, per David. adjust comment to use 80 cols, per Andrew. Reviewed-by: Christian Borntraeger <[email protected]> Acked-by: David Rientjes <[email protected]> Signed-off-by: Joonsoo Kim <[email protected]> --- mm/vmalloc.c | 25 ++++++++++++------------- 1 file changed, 12 insertions(+), 13 deletions(-) diff --git a/mm/vmalloc.c b/mm/vmalloc.c index fb42a5b..d4b2e34 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -531,22 +531,21 @@ static void unmap_vmap_area(struct vmap_area *va) static void vmap_debug_free_range(unsigned long start, unsigned long end) { /* - * Unmap page tables and force a TLB flush immediately if - * CONFIG_DEBUG_PAGEALLOC is set. This catches use after free - * bugs similarly to those in linear kernel virtual address - * space after a page has been freed. + * Unmap page tables and force a TLB flush immediately if pagealloc + * debugging is enabled. This catches use after free bugs similarly to + * those in linear kernel virtual address space after a page has been + * freed. * - * All the lazy freeing logic is still retained, in order to - * minimise intrusiveness of this debugging feature. + * All the lazy freeing logic is still retained, in order to minimise + * intrusiveness of this debugging feature. * - * This is going to be *slow* (linear kernel virtual address - * debugging doesn't do a broadcast TLB flush so it is a lot - * faster). + * This is going to be *slow* (linear kernel virtual address debugging + * doesn't do a broadcast TLB flush so it is a lot faster). */ -#ifdef CONFIG_DEBUG_PAGEALLOC - vunmap_page_range(start, end); - flush_tlb_kernel_range(start, end); -#endif + if (debug_pagealloc_enabled()) { + vunmap_page_range(start, end); + flush_tlb_kernel_range(start, end); + } } /* -- 1.9.1
