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authorLong Li <lonuxli.64@gmail.com>2020-08-06 23:18:28 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-08-07 11:33:22 -0700
commit444050990db4abdf0c85ca6050542b888ba316a1 (patch)
tree94acbfbb4ec5aef67b237176977b953c7c8ad929 /mm/slab_common.c
parentdabc3e291d56e3125113101bc6d53d1a1738294d (diff)
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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 <lonuxli.64@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Pekka Enberg <penberg@kernel.org> Acked-by: David Rientjes <rientjes@google.com> Cc: Christoph Lameter <cl@linux.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Link: http://lkml.kernel.org/r/20200704035027.GA62481@lilong Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/slab_common.c')
-rw-r--r--mm/slab_common.c17
1 files changed, 17 insertions, 0 deletions
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 <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_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)) {