From 444050990db4abdf0c85ca6050542b888ba316a1 Mon Sep 17 00:00:00 2001 From: Long Li Date: Thu, 6 Aug 2020 23:18:28 -0700 Subject: mm, slab: check GFP_SLAB_BUG_MASK before alloc_pages in kmalloc_order kmalloc cannot allocate memory from HIGHMEM. Allocating large amounts of memory currently bypasses the check and will simply leak the memory when page_address() returns NULL. To fix this, factor the GFP_SLAB_BUG_MASK check out of slab & slub, and call it from kmalloc_order() as well. In order to make the code clear, the warning message is put in one place. Signed-off-by: Long Li Signed-off-by: Andrew Morton Reviewed-by: Matthew Wilcox (Oracle) Reviewed-by: Pekka Enberg Acked-by: David Rientjes Cc: Christoph Lameter Cc: Joonsoo Kim Link: http://lkml.kernel.org/r/20200704035027.GA62481@lilong Signed-off-by: Linus Torvalds --- mm/slab_common.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) (limited to 'mm/slab_common.c') diff --git a/mm/slab_common.c b/mm/slab_common.c index e493203b5002..616ec8a0d91a 100644 --- a/mm/slab_common.c +++ b/mm/slab_common.c @@ -26,6 +26,8 @@ #define CREATE_TRACE_POINTS #include +#include "internal.h" + #include "slab.h" enum slab_state slab_state; @@ -1332,6 +1334,18 @@ void __init create_kmalloc_caches(slab_flags_t flags) } #endif /* !CONFIG_SLOB */ +gfp_t kmalloc_fix_flags(gfp_t flags) +{ + gfp_t invalid_mask = flags & GFP_SLAB_BUG_MASK; + + flags &= ~GFP_SLAB_BUG_MASK; + pr_warn("Unexpected gfp: %#x (%pGg). Fixing up to gfp: %#x (%pGg). Fix your code!\n", + invalid_mask, &invalid_mask, flags, &flags); + dump_stack(); + + return flags; +} + /* * To avoid unnecessary overhead, we pass through large allocation requests * directly to the page allocator. We use __GFP_COMP, because we will need to @@ -1342,6 +1356,9 @@ void *kmalloc_order(size_t size, gfp_t flags, unsigned int order) void *ret = NULL; struct page *page; + if (unlikely(flags & GFP_SLAB_BUG_MASK)) + flags = kmalloc_fix_flags(flags); + flags |= __GFP_COMP; page = alloc_pages(flags, order); if (likely(page)) { -- cgit