diff options
| -rw-r--r-- | include/linux/gfp.h | 25 | ||||
| -rw-r--r-- | mm/kmemleak.c | 12 |
2 files changed, 29 insertions, 8 deletions
diff --git a/include/linux/gfp.h b/include/linux/gfp.h index 450c2cbcf04b..7f9691d375f0 100644 --- a/include/linux/gfp.h +++ b/include/linux/gfp.h @@ -157,6 +157,31 @@ static inline int gfp_zonelist(gfp_t flags) } /* + * gfp flag masking for nested internal allocations. + * + * For code that needs to do allocations inside the public allocation API (e.g. + * memory allocation tracking code) the allocations need to obey the caller + * allocation context constrains to prevent allocation context mismatches (e.g. + * GFP_KERNEL allocations in GFP_NOFS contexts) from potential deadlock + * situations. + * + * It is also assumed that these nested allocations are for internal kernel + * object storage purposes only and are not going to be used for DMA, etc. Hence + * we strip out all the zone information and leave just the context information + * intact. + * + * Further, internal allocations must fail before the higher level allocation + * can fail, so we must make them fail faster and fail silently. We also don't + * want them to deplete emergency reserves. Hence nested allocations must be + * prepared for these allocations to fail. + */ +static inline gfp_t gfp_nested_mask(gfp_t flags) +{ + return ((flags & (GFP_KERNEL | GFP_ATOMIC | __GFP_NOLOCKDEP)) | + (__GFP_NORETRY | __GFP_NOMEMALLOC | __GFP_NOWARN)); +} + +/* * We get the zone list from the current node and the gfp_mask. * This zone list contains a maximum of MAX_NUMNODES*MAX_NR_ZONES zones. * There are two zonelists per node, one for all zones with memory and diff --git a/mm/kmemleak.c b/mm/kmemleak.c index fdcf01f62202..d5b6fba44fc9 100644 --- a/mm/kmemleak.c +++ b/mm/kmemleak.c @@ -114,12 +114,6 @@ #define BYTES_PER_POINTER sizeof(void *) -/* GFP bitmask for kmemleak internal allocations */ -#define gfp_kmemleak_mask(gfp) (((gfp) & (GFP_KERNEL | GFP_ATOMIC | \ - __GFP_NOLOCKDEP)) | \ - __GFP_NORETRY | __GFP_NOMEMALLOC | \ - __GFP_NOWARN) - /* scanning area inside a memory block */ struct kmemleak_scan_area { struct hlist_node node; @@ -463,7 +457,8 @@ static struct kmemleak_object *mem_pool_alloc(gfp_t gfp) /* try the slab allocator first */ if (object_cache) { - object = kmem_cache_alloc_noprof(object_cache, gfp_kmemleak_mask(gfp)); + object = kmem_cache_alloc_noprof(object_cache, + gfp_nested_mask(gfp)); if (object) return object; } @@ -947,7 +942,8 @@ static void add_scan_area(unsigned long ptr, size_t size, gfp_t gfp) untagged_objp = (unsigned long)kasan_reset_tag((void *)object->pointer); if (scan_area_cache) - area = kmem_cache_alloc_noprof(scan_area_cache, gfp_kmemleak_mask(gfp)); + area = kmem_cache_alloc_noprof(scan_area_cache, + gfp_nested_mask(gfp)); raw_spin_lock_irqsave(&object->lock, flags); if (!area) { |