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 <lonuxli.64@xxxxxxxxx>
---
changes in V4:
-Change the check function name to kmalloc_check_flags()
-Put the flags check into the kmalloc_check_flags()
changes in V3:
-Put the warning message in one place
-updage the change log to be clear
mm/slab.c | 8 +-------
mm/slab.h | 1 +
mm/slab_common.c | 18 +++++++++++++++++-
mm/slub.c | 8 +-------
4 files changed, 20 insertions(+), 15 deletions(-)
diff --git a/mm/slab.c b/mm/slab.c
index ac7a223d9ac3..755f33f96f04 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -2573,13 +2573,7 @@ static struct page *cache_grow_begin(struct kmem_cache *cachep,
* 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();
- }
+ flags = kmalloc_check_flags(flags);
WARN_ON_ONCE(cachep->ctor && (flags & __GFP_ZERO));
local_flags = flags & (GFP_CONSTRAINT_MASK|GFP_RECLAIM_MASK);
diff --git a/mm/slab.h b/mm/slab.h
index a06f3313e4a0..48df5660764c 100644
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -90,6 +90,7 @@ void create_kmalloc_caches(slab_flags_t);
struct kmem_cache *kmalloc_slab(size_t, gfp_t);
#endif
+gfp_t kmalloc_check_flags(gfp_t flags);
/* Functions provided by the slab allocators */
int __kmem_cache_create(struct kmem_cache *, slab_flags_t flags);
diff --git a/mm/slab_common.c b/mm/slab_common.c
index a143a8c8f874..9184e4575d6d 100644
--- a/mm/slab_common.c
+++ b/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;
@@ -805,6 +807,20 @@ void __init create_kmalloc_caches(slab_flags_t flags)
}
#endif /* !CONFIG_SLOB */
+gfp_t kmalloc_check_flags(gfp_t flags)
+{
+ 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();
+ }
+
+ 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
@@ -815,7 +831,7 @@ void *kmalloc_order(size_t size, gfp_t flags, unsigned int order)
void *ret = NULL;
struct page *page;
- flags |= __GFP_COMP;
+ flags = kmalloc_check_flags(flags) | __GFP_COMP;
page = alloc_pages(flags, order);
if (likely(page)) {
ret = page_address(page);
diff --git a/mm/slub.c b/mm/slub.c
index 62d2de56549e..8e787767850f 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -1817,13 +1817,7 @@ static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
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();
- }
+ flags = kmalloc_check_flags(flags);
return allocate_slab(s,
flags & (GFP_RECLAIM_MASK | GFP_CONSTRAINT_MASK), node);
--
2.17.1
