From: Long Li <lonuxli.64@xxxxxxxxx> 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. Link: http://lkml.kernel.org/r/20200704035027.GA62481@lilong Signed-off-by: Long Li <lonuxli.64@xxxxxxxxx> Reviewed-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx> Reviewed-by: Pekka Enberg <penberg@xxxxxxxxxx> Acked-by: David Rientjes <rientjes@xxxxxxxxxx> Cc: Christoph Lameter <cl@xxxxxxxxx> Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/slab.c | 10 +++------- mm/slab.h | 1 + mm/slab_common.c | 17 +++++++++++++++++ mm/slub.c | 9 ++------- 4 files changed, 23 insertions(+), 14 deletions(-) --- a/mm/slab.c~mm-slab-check-gfp_slab_bug_mask-before-alloc_pages-in-kmalloc_order +++ a/mm/slab.c @@ -2589,13 +2589,9 @@ static struct page *cache_grow_begin(str * Be lazy and only check for valid flags here, keeping it out of the * critical path in kmem_cache_alloc(). */ - if (unlikely(flags & GFP_SLAB_BUG_MASK)) { - 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(); - } + if (unlikely(flags & GFP_SLAB_BUG_MASK)) + flags = kmalloc_fix_flags(flags); + WARN_ON_ONCE(cachep->ctor && (flags & __GFP_ZERO)); local_flags = flags & (GFP_CONSTRAINT_MASK|GFP_RECLAIM_MASK); --- a/mm/slab_common.c~mm-slab-check-gfp_slab_bug_mask-before-alloc_pages-in-kmalloc_order +++ a/mm/slab_common.c @@ -26,6 +26,8 @@ #define CREATE_TRACE_POINTS #include <trace/events/kmem.h> +#include "internal.h" + #include "slab.h" enum slab_state slab_state; @@ -1332,6 +1334,18 @@ void __init create_kmalloc_caches(slab_f } #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 f 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)) { --- a/mm/slab.h~mm-slab-check-gfp_slab_bug_mask-before-alloc_pages-in-kmalloc_order +++ a/mm/slab.h @@ -152,6 +152,7 @@ void create_kmalloc_caches(slab_flags_t) struct kmem_cache *kmalloc_slab(size_t, gfp_t); #endif +gfp_t kmalloc_fix_flags(gfp_t flags); /* Functions provided by the slab allocators */ int __kmem_cache_create(struct kmem_cache *, slab_flags_t flags); --- a/mm/slub.c~mm-slab-check-gfp_slab_bug_mask-before-alloc_pages-in-kmalloc_order +++ a/mm/slub.c @@ -1745,13 +1745,8 @@ out: static struct page *new_slab(struct kmem_cache *s, gfp_t flags, int node) { - if (unlikely(flags & GFP_SLAB_BUG_MASK)) { - 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(); - } + if (unlikely(flags & GFP_SLAB_BUG_MASK)) + flags = kmalloc_fix_flags(flags); return allocate_slab(s, flags & (GFP_RECLAIM_MASK | GFP_CONSTRAINT_MASK), node); _
