* [PATCH v3 1/2] slab: support for compiler-assisted type-based slab cache partitioning
@ 2026-04-24 13:24 Marco Elver
2026-04-24 13:24 ` [PATCH v3 2/2] slab: fix kernel-docs for mm-api Marco Elver
0 siblings, 1 reply; 2+ messages in thread
From: Marco Elver @ 2026-04-24 13:24 UTC (permalink / raw)
To: elver, Vlastimil Babka, Andrew Morton
Cc: Nathan Chancellor, Nicolas Schier, Dennis Zhou, Tejun Heo,
Christoph Lameter, Harry Yoo, Hao Li, David Rientjes,
Roman Gushchin, Kees Cook, Gustavo A. R. Silva, David Hildenbrand,
Lorenzo Stoakes, Liam R. Howlett, Mike Rapoport,
Suren Baghdasaryan, Michal Hocko, Alexander Potapenko,
Dmitry Vyukov, Nick Desaulniers, Bill Wendling, Justin Stitt,
Miguel Ojeda, linux-kbuild, linux-kernel, linux-mm,
linux-hardening, kasan-dev, llvm, Andrey Konovalov,
Florent Revest, Jann Horn, KP Singh, Matteo Rizzo, GONG Ruiqi
Rework the general infrastructure around RANDOM_KMALLOC_CACHES into more
flexible KMALLOC_PARTITION_CACHES, with the former being a partitioning
mode of the latter.
Introduce a new mode, KMALLOC_PARTITION_TYPED, which leverages a feature
available in Clang 22 and later, called "allocation tokens" via
__builtin_infer_alloc_token() [1]. Unlike KMALLOC_PARTITION_RANDOM
(formerly RANDOM_KMALLOC_CACHES), this mode deterministically assigns a
slab cache to an allocation of type T, regardless of allocation site.
The builtin __builtin_infer_alloc_token(<malloc-args>, ...) instructs
the compiler to infer an allocation type from arguments commonly passed
to memory-allocating functions and returns a type-derived token ID. The
implementation passes kmalloc-args to the builtin: the compiler performs
best-effort type inference, and then recognizes common patterns such as
`kmalloc(sizeof(T), ...)`, `kmalloc(sizeof(T) * n, ...)`, but also
`(T *)kmalloc(...)`. Where the compiler fails to infer a type the
fallback token (default: 0) is chosen.
Note: kmalloc_obj(..) APIs fix the pattern how size and result type are
expressed, and therefore ensures there's not much drift in which
patterns the compiler needs to recognize. Specifically, kmalloc_obj()
and friends expand to `(TYPE *)KMALLOC(__obj_size, GFP)`, which the
compiler recognizes via the cast to TYPE*.
Clang's default token ID calculation is described as [1]:
typehashpointersplit: This mode assigns a token ID based on the hash
of the allocated type's name, where the top half ID-space is reserved
for types that contain pointers and the bottom half for types that do
not contain pointers.
Separating pointer-containing objects from pointerless objects and data
allocations can help mitigate certain classes of memory corruption
exploits [2]: attackers who gains a buffer overflow on a primitive
buffer cannot use it to directly corrupt pointers or other critical
metadata in an object residing in a different, isolated heap region.
It is important to note that heap isolation strategies offer a
best-effort approach, and do not provide a 100% security guarantee,
albeit achievable at relatively low performance cost. Note that this
also does not prevent cross-cache attacks: while waiting for future
features like SLAB_VIRTUAL [3] to provide physical page isolation, this
feature should be deployed alongside SHUFFLE_PAGE_ALLOCATOR and
init_on_free=1 to mitigate cross-cache attacks and page-reuse attacks as
much as possible today.
With all that, my kernel (x86 defconfig) shows me a histogram of slab
cache object distribution per /proc/slabinfo (after boot):
<slab cache> <objs> <hist>
kmalloc-part-15 1465 ++++++++++++++
kmalloc-part-14 2988 +++++++++++++++++++++++++++++
kmalloc-part-13 1656 ++++++++++++++++
kmalloc-part-12 1045 ++++++++++
kmalloc-part-11 1697 ++++++++++++++++
kmalloc-part-10 1489 ++++++++++++++
kmalloc-part-09 965 +++++++++
kmalloc-part-08 710 +++++++
kmalloc-part-07 100 +
kmalloc-part-06 217 ++
kmalloc-part-05 105 +
kmalloc-part-04 4047 ++++++++++++++++++++++++++++++++++++++++
kmalloc-part-03 183 +
kmalloc-part-02 283 ++
kmalloc-part-01 316 +++
kmalloc 1422 ++++++++++++++
The above /proc/slabinfo snapshot shows me there are 6673 allocated
objects (slabs 00 - 07) that the compiler claims contain no pointers or
it was unable to infer the type of, and 12015 objects that contain
pointers (slabs 08 - 15). On a whole, this looks relatively sane.
Additionally, when I compile my kernel with -Rpass=alloc-token, which
provides diagnostics where (after dead-code elimination) type inference
failed, I see 186 allocation sites where the compiler failed to identify
a type (down from 966 when I sent the RFC [4]). Some initial review
confirms these are mostly variable sized buffers, but also include
structs with trailing flexible length arrays.
Link: https://clang.llvm.org/docs/AllocToken.html [1]
Link: https://blog.dfsec.com/ios/2025/05/30/blasting-past-ios-18/ [2]
Link: https://lwn.net/Articles/944647/ [3]
Link: https://lore.kernel.org/all/20250825154505.1558444-1-elver@google.com/ [4]
Link: https://discourse.llvm.org/t/rfc-a-framework-for-allocator-partitioning-hints/87434
Acked-by: GONG Ruiqi <gongruiqi1@huawei.com>
Co-developed-by: Harry Yoo (Oracle) <harry@kernel.org>
Signed-off-by: Harry Yoo (Oracle) <harry@kernel.org>
Signed-off-by: Marco Elver <elver@google.com>
---
v3:
* Introduce DECL_TOKEN_PARAMS / PASS_TOKEN_PARAMS (suggested-by Harry).
* Rename {RANDOM,TYPED}_KMALLOC_CACHES to KMALLOC_PARTITION_{RANDOM,TYPED},
so it's more easily searchable and consistent with the top-level name
with the variant at the end of the CONFIG phrase (reported-by Kees).
* Make KMALLOC_PARTITION_TYPED default if available (suggested-by Kees).
* Add RANDOM_KMALLOC_CACHES transitional option (suggested-by Kees).
* Add CC_HAS_ALLOC_TOKEN and use it (reported-by Kees).
v2: https://lore.kernel.org/all/20260415143735.2974230-1-elver@google.com/
* Avoid empty function argument if !KMALLOC_PARTITION_CACHES
(co-developed-by Harry). While Clang does optimize out the empty
struct argument (and generated code is identical to before if
KMALLOC_PARTITION_CACHES is disabled), GCC doesn't do so. So we need
to fully remove the argument if not actually required.
* Cover krealloc() which was missed before, resulting in ~100 additional
objects in the pointer-containing caches in above histogram.
* Unify kmalloc_token_t definition.
* Expand Kconfig help text.
v1: https://lore.kernel.org/all/20260331111240.153913-1-elver@google.com/
* Rebase and switch to builtin name that was released in Clang 22.
* Keep RANDOM_KMALLOC_CACHES the default.
RFC: https://lore.kernel.org/all/20250825154505.1558444-1-elver@google.com/
---
Makefile | 5 ++
include/linux/percpu.h | 2 +-
include/linux/slab.h | 136 +++++++++++++++++++++-----------
init/Kconfig | 3 +
kernel/configs/hardening.config | 2 +-
mm/Kconfig | 73 ++++++++++++++---
mm/kfence/kfence_test.c | 4 +-
mm/slab.h | 4 +-
mm/slab_common.c | 52 ++++++------
mm/slub.c | 54 +++++++------
10 files changed, 220 insertions(+), 115 deletions(-)
diff --git a/Makefile b/Makefile
index 54e1ae602000..afe663bdb9c0 100644
--- a/Makefile
+++ b/Makefile
@@ -989,6 +989,11 @@ KBUILD_CFLAGS += $(CC_AUTO_VAR_INIT_ZERO_ENABLER)
endif
endif
+ifdef CONFIG_KMALLOC_PARTITION_TYPED
+# KMALLOC_PARTITION_CACHES_NR + 1
+KBUILD_CFLAGS += -falloc-token-max=16
+endif
+
ifdef CONFIG_CC_IS_CLANG
ifdef CONFIG_CC_HAS_COUNTED_BY_PTR
KBUILD_CFLAGS += -fexperimental-late-parse-attributes
diff --git a/include/linux/percpu.h b/include/linux/percpu.h
index 85bf8dd9f087..bdb721dac0e3 100644
--- a/include/linux/percpu.h
+++ b/include/linux/percpu.h
@@ -36,7 +36,7 @@
#define PCPU_BITMAP_BLOCK_BITS (PCPU_BITMAP_BLOCK_SIZE >> \
PCPU_MIN_ALLOC_SHIFT)
-#ifdef CONFIG_RANDOM_KMALLOC_CACHES
+#ifdef CONFIG_KMALLOC_PARTITION_CACHES
# if defined(CONFIG_LOCKDEP) && !defined(CONFIG_PAGE_SIZE_4KB)
# define PERCPU_DYNAMIC_SIZE_SHIFT 13
# else
diff --git a/include/linux/slab.h b/include/linux/slab.h
index 15a60b501b95..c232f8a10af6 100644
--- a/include/linux/slab.h
+++ b/include/linux/slab.h
@@ -499,14 +499,38 @@ int kmem_cache_shrink(struct kmem_cache *s);
.usersize = sizeof_field(struct __struct, __field), \
}, (__flags))
+#ifdef CONFIG_KMALLOC_PARTITION_CACHES
+typedef struct { unsigned long v; } kmalloc_token_t;
+#ifdef CONFIG_KMALLOC_PARTITION_RANDOM
+extern unsigned long random_kmalloc_seed;
+#define __kmalloc_token(...) ((kmalloc_token_t){ .v = _RET_IP_ })
+#elif defined(CONFIG_KMALLOC_PARTITION_TYPED)
+#define __kmalloc_token(...) ((kmalloc_token_t){ .v = __builtin_infer_alloc_token(__VA_ARGS__) })
+#endif
+#define DECL_TOKEN_PARAM(_token) , kmalloc_token_t (_token)
+#define _PASS_TOKEN_PARAM(_token) , (_token)
+#define PASS_TOKEN_PARAM(_token) (_token)
+#define DECL_TOKEN_PARAMS(_size, _token) size_t (_size), kmalloc_token_t (_token)
+#define PASS_TOKEN_PARAMS(_size, _token) (_size), (_token)
+#else /* !CONFIG_KMALLOC_PARTITION_CACHES */
+typedef struct {} kmalloc_token_t;
+#define __kmalloc_token(...) ((kmalloc_token_t){}) /* no-op */
+#define DECL_TOKEN_PARAM(_token)
+#define _PASS_TOKEN_PARAM(_token)
+#define PASS_TOKEN_PARAM(_token) ((kmalloc_token_t){})
+#define DECL_TOKEN_PARAMS(_size, _token) size_t (_size)
+#define PASS_TOKEN_PARAMS(_size, _token) (_size)
+#endif /* CONFIG_KMALLOC_PARTITION_CACHES */
+
/*
* Common kmalloc functions provided by all allocators
*/
-void * __must_check krealloc_node_align_noprof(const void *objp, size_t new_size,
+void * __must_check krealloc_node_align_noprof(const void *objp,
+ DECL_TOKEN_PARAMS(new_size, token),
unsigned long align,
gfp_t flags, int nid) __realloc_size(2);
-#define krealloc_noprof(_o, _s, _f) krealloc_node_align_noprof(_o, _s, 1, _f, NUMA_NO_NODE)
-#define krealloc_node_align(...) alloc_hooks(krealloc_node_align_noprof(__VA_ARGS__))
+#define krealloc_noprof(_o, _s, _f) krealloc_node_align_noprof(_o, PASS_TOKEN_PARAMS(_s, __kmalloc_token(_s)), 1, _f, NUMA_NO_NODE)
+#define krealloc_node_align(_o, _s, _a, _f, _n) alloc_hooks(krealloc_node_align_noprof(_o, PASS_TOKEN_PARAMS(_s, __kmalloc_token(_s)), _a, _f, _n))
#define krealloc_node(_o, _s, _f, _n) krealloc_node_align(_o, _s, 1, _f, _n)
#define krealloc(...) krealloc_node(__VA_ARGS__, NUMA_NO_NODE)
@@ -612,10 +636,10 @@ static inline unsigned int arch_slab_minalign(void)
#define SLAB_OBJ_MIN_SIZE (KMALLOC_MIN_SIZE < 16 ? \
(KMALLOC_MIN_SIZE) : 16)
-#ifdef CONFIG_RANDOM_KMALLOC_CACHES
-#define RANDOM_KMALLOC_CACHES_NR 15 // # of cache copies
+#ifdef CONFIG_KMALLOC_PARTITION_CACHES
+#define KMALLOC_PARTITION_CACHES_NR 15 // # of cache copies
#else
-#define RANDOM_KMALLOC_CACHES_NR 0
+#define KMALLOC_PARTITION_CACHES_NR 0
#endif
/*
@@ -634,8 +658,8 @@ enum kmalloc_cache_type {
#ifndef CONFIG_MEMCG
KMALLOC_CGROUP = KMALLOC_NORMAL,
#endif
- KMALLOC_RANDOM_START = KMALLOC_NORMAL,
- KMALLOC_RANDOM_END = KMALLOC_RANDOM_START + RANDOM_KMALLOC_CACHES_NR,
+ KMALLOC_PARTITION_START = KMALLOC_NORMAL,
+ KMALLOC_PARTITION_END = KMALLOC_PARTITION_START + KMALLOC_PARTITION_CACHES_NR,
#ifdef CONFIG_SLUB_TINY
KMALLOC_RECLAIM = KMALLOC_NORMAL,
#else
@@ -662,19 +686,19 @@ extern kmem_buckets kmalloc_caches[NR_KMALLOC_TYPES];
(IS_ENABLED(CONFIG_ZONE_DMA) ? __GFP_DMA : 0) | \
(IS_ENABLED(CONFIG_MEMCG) ? __GFP_ACCOUNT : 0))
-extern unsigned long random_kmalloc_seed;
-
-static __always_inline enum kmalloc_cache_type kmalloc_type(gfp_t flags, unsigned long caller)
+static __always_inline enum kmalloc_cache_type kmalloc_type(gfp_t flags, kmalloc_token_t token)
{
/*
* The most common case is KMALLOC_NORMAL, so test for it
* with a single branch for all the relevant flags.
*/
if (likely((flags & KMALLOC_NOT_NORMAL_BITS) == 0))
-#ifdef CONFIG_RANDOM_KMALLOC_CACHES
- /* RANDOM_KMALLOC_CACHES_NR (=15) copies + the KMALLOC_NORMAL */
- return KMALLOC_RANDOM_START + hash_64(caller ^ random_kmalloc_seed,
- ilog2(RANDOM_KMALLOC_CACHES_NR + 1));
+#ifdef CONFIG_KMALLOC_PARTITION_RANDOM
+ /* KMALLOC_PARTITION_CACHES_NR (=15) copies + the KMALLOC_NORMAL */
+ return KMALLOC_PARTITION_START + hash_64(token.v ^ random_kmalloc_seed,
+ ilog2(KMALLOC_PARTITION_CACHES_NR + 1));
+#elif defined(CONFIG_KMALLOC_PARTITION_TYPED)
+ return KMALLOC_PARTITION_START + token.v;
#else
return KMALLOC_NORMAL;
#endif
@@ -858,16 +882,22 @@ unsigned int kmem_cache_sheaf_size(struct slab_sheaf *sheaf);
#define PASS_BUCKET_PARAM(_b) NULL
#endif
+#define DECL_KMALLOC_PARAMS(_size, _b, _token) DECL_BUCKET_PARAMS(_size, _b) \
+ DECL_TOKEN_PARAM(_token)
+
+#define PASS_KMALLOC_PARAMS(_size, _b, _token) PASS_BUCKET_PARAMS(_size, _b) \
+ _PASS_TOKEN_PARAM(_token)
+
/*
* The following functions are not to be used directly and are intended only
* for internal use from kmalloc() and kmalloc_node()
* with the exception of kunit tests
*/
-void *__kmalloc_noprof(size_t size, gfp_t flags)
+void *__kmalloc_noprof(DECL_KMALLOC_PARAMS(size, b, token), gfp_t flags)
__assume_kmalloc_alignment __alloc_size(1);
-void *__kmalloc_node_noprof(DECL_BUCKET_PARAMS(size, b), gfp_t flags, int node)
+void *__kmalloc_node_noprof(DECL_KMALLOC_PARAMS(size, b, token), gfp_t flags, int node)
__assume_kmalloc_alignment __alloc_size(1);
void *__kmalloc_cache_noprof(struct kmem_cache *s, gfp_t flags, size_t size)
@@ -938,7 +968,7 @@ void *__kmalloc_large_node_noprof(size_t size, gfp_t flags, int node)
* Try really hard to succeed the allocation but fail
* eventually.
*/
-static __always_inline __alloc_size(1) void *kmalloc_noprof(size_t size, gfp_t flags)
+static __always_inline __alloc_size(1) void *_kmalloc_noprof(size_t size, gfp_t flags, kmalloc_token_t token)
{
if (__builtin_constant_p(size) && size) {
unsigned int index;
@@ -948,14 +978,16 @@ static __always_inline __alloc_size(1) void *kmalloc_noprof(size_t size, gfp_t f
index = kmalloc_index(size);
return __kmalloc_cache_noprof(
- kmalloc_caches[kmalloc_type(flags, _RET_IP_)][index],
+ kmalloc_caches[kmalloc_type(flags, token)][index],
flags, size);
}
- return __kmalloc_noprof(size, flags);
+ return __kmalloc_noprof(PASS_KMALLOC_PARAMS(size, NULL, token), flags);
}
+#define kmalloc_noprof(...) _kmalloc_noprof(__VA_ARGS__, __kmalloc_token(__VA_ARGS__))
#define kmalloc(...) alloc_hooks(kmalloc_noprof(__VA_ARGS__))
-void *kmalloc_nolock_noprof(size_t size, gfp_t gfp_flags, int node);
+void *_kmalloc_nolock_noprof(DECL_TOKEN_PARAMS(size, token), gfp_t gfp_flags, int node);
+#define kmalloc_nolock_noprof(_s, _f, _n) _kmalloc_nolock_noprof(PASS_TOKEN_PARAMS(_s, __kmalloc_token(_s)), _f, _n)
#define kmalloc_nolock(...) alloc_hooks(kmalloc_nolock_noprof(__VA_ARGS__))
/**
@@ -1060,12 +1092,12 @@ void *kmalloc_nolock_noprof(size_t size, gfp_t gfp_flags, int node);
__alloc_flex(kvzalloc, default_gfp(__VA_ARGS__), typeof(P), FAM, COUNT)
#define kmem_buckets_alloc(_b, _size, _flags) \
- alloc_hooks(__kmalloc_node_noprof(PASS_BUCKET_PARAMS(_size, _b), _flags, NUMA_NO_NODE))
+ alloc_hooks(__kmalloc_node_noprof(PASS_KMALLOC_PARAMS(_size, _b, __kmalloc_token(_size)), _flags, NUMA_NO_NODE))
#define kmem_buckets_alloc_track_caller(_b, _size, _flags) \
- alloc_hooks(__kmalloc_node_track_caller_noprof(PASS_BUCKET_PARAMS(_size, _b), _flags, NUMA_NO_NODE, _RET_IP_))
+ alloc_hooks(__kmalloc_node_track_caller_noprof(PASS_KMALLOC_PARAMS(_size, _b, __kmalloc_token(_size)), _flags, NUMA_NO_NODE, _RET_IP_))
-static __always_inline __alloc_size(1) void *kmalloc_node_noprof(size_t size, gfp_t flags, int node)
+static __always_inline __alloc_size(1) void *_kmalloc_node_noprof(size_t size, gfp_t flags, int node, kmalloc_token_t token)
{
if (__builtin_constant_p(size) && size) {
unsigned int index;
@@ -1075,11 +1107,12 @@ static __always_inline __alloc_size(1) void *kmalloc_node_noprof(size_t size, gf
index = kmalloc_index(size);
return __kmalloc_cache_node_noprof(
- kmalloc_caches[kmalloc_type(flags, _RET_IP_)][index],
+ kmalloc_caches[kmalloc_type(flags, token)][index],
flags, node, size);
}
- return __kmalloc_node_noprof(PASS_BUCKET_PARAMS(size, NULL), flags, node);
+ return __kmalloc_node_noprof(PASS_KMALLOC_PARAMS(size, NULL, token), flags, node);
}
+#define kmalloc_node_noprof(...) _kmalloc_node_noprof(__VA_ARGS__, __kmalloc_token(__VA_ARGS__))
#define kmalloc_node(...) alloc_hooks(kmalloc_node_noprof(__VA_ARGS__))
/**
@@ -1088,14 +1121,15 @@ static __always_inline __alloc_size(1) void *kmalloc_node_noprof(size_t size, gf
* @size: element size.
* @flags: the type of memory to allocate (see kmalloc).
*/
-static inline __alloc_size(1, 2) void *kmalloc_array_noprof(size_t n, size_t size, gfp_t flags)
+static inline __alloc_size(1, 2) void *_kmalloc_array_noprof(size_t n, size_t size, gfp_t flags, kmalloc_token_t token)
{
size_t bytes;
if (unlikely(check_mul_overflow(n, size, &bytes)))
return NULL;
- return kmalloc_noprof(bytes, flags);
+ return _kmalloc_noprof(bytes, flags, token);
}
+#define kmalloc_array_noprof(...) _kmalloc_array_noprof(__VA_ARGS__, __kmalloc_token(__VA_ARGS__))
#define kmalloc_array(...) alloc_hooks(kmalloc_array_noprof(__VA_ARGS__))
/**
@@ -1115,18 +1149,19 @@ static inline __alloc_size(1, 2) void *kmalloc_array_noprof(size_t n, size_t siz
* In any case, the contents of the object pointed to are preserved up to the
* lesser of the new and old sizes.
*/
-static inline __realloc_size(2, 3) void * __must_check krealloc_array_noprof(void *p,
+static inline __realloc_size(2, 3) void * __must_check _krealloc_array_noprof(void *p,
size_t new_n,
size_t new_size,
- gfp_t flags)
+ gfp_t flags, kmalloc_token_t token)
{
size_t bytes;
if (unlikely(check_mul_overflow(new_n, new_size, &bytes)))
return NULL;
- return krealloc_noprof(p, bytes, flags);
+ return krealloc_node_align_noprof(p, PASS_TOKEN_PARAMS(bytes, token), 1, flags, NUMA_NO_NODE);
}
+#define krealloc_array_noprof(...) _krealloc_array_noprof(__VA_ARGS__, __kmalloc_token(__VA_ARGS__))
#define krealloc_array(...) alloc_hooks(krealloc_array_noprof(__VA_ARGS__))
/**
@@ -1137,10 +1172,10 @@ static inline __realloc_size(2, 3) void * __must_check krealloc_array_noprof(voi
*/
#define kcalloc(n, size, flags) kmalloc_array(n, size, (flags) | __GFP_ZERO)
-void *__kmalloc_node_track_caller_noprof(DECL_BUCKET_PARAMS(size, b), gfp_t flags, int node,
+void *__kmalloc_node_track_caller_noprof(DECL_KMALLOC_PARAMS(size, b, token), gfp_t flags, int node,
unsigned long caller) __alloc_size(1);
#define kmalloc_node_track_caller_noprof(size, flags, node, caller) \
- __kmalloc_node_track_caller_noprof(PASS_BUCKET_PARAMS(size, NULL), flags, node, caller)
+ __kmalloc_node_track_caller_noprof(PASS_KMALLOC_PARAMS(size, NULL, __kmalloc_token(size)), flags, node, caller)
#define kmalloc_node_track_caller(...) \
alloc_hooks(kmalloc_node_track_caller_noprof(__VA_ARGS__, _RET_IP_))
@@ -1157,17 +1192,18 @@ void *__kmalloc_node_track_caller_noprof(DECL_BUCKET_PARAMS(size, b), gfp_t flag
#define kmalloc_track_caller_noprof(...) \
kmalloc_node_track_caller_noprof(__VA_ARGS__, NUMA_NO_NODE, _RET_IP_)
-static inline __alloc_size(1, 2) void *kmalloc_array_node_noprof(size_t n, size_t size, gfp_t flags,
- int node)
+static inline __alloc_size(1, 2) void *_kmalloc_array_node_noprof(size_t n, size_t size, gfp_t flags,
+ int node, kmalloc_token_t token)
{
size_t bytes;
if (unlikely(check_mul_overflow(n, size, &bytes)))
return NULL;
if (__builtin_constant_p(n) && __builtin_constant_p(size))
- return kmalloc_node_noprof(bytes, flags, node);
- return __kmalloc_node_noprof(PASS_BUCKET_PARAMS(bytes, NULL), flags, node);
+ return _kmalloc_node_noprof(bytes, flags, node, token);
+ return __kmalloc_node_noprof(PASS_KMALLOC_PARAMS(bytes, NULL, token), flags, node);
}
+#define kmalloc_array_node_noprof(...) _kmalloc_array_node_noprof(__VA_ARGS__, __kmalloc_token(__VA_ARGS__))
#define kmalloc_array_node(...) alloc_hooks(kmalloc_array_node_noprof(__VA_ARGS__))
#define kcalloc_node(_n, _size, _flags, _node) \
@@ -1183,39 +1219,43 @@ static inline __alloc_size(1, 2) void *kmalloc_array_node_noprof(size_t n, size_
* @size: how many bytes of memory are required.
* @flags: the type of memory to allocate (see kmalloc).
*/
-static inline __alloc_size(1) void *kzalloc_noprof(size_t size, gfp_t flags)
+static inline __alloc_size(1) void *_kzalloc_noprof(size_t size, gfp_t flags, kmalloc_token_t token)
{
- return kmalloc_noprof(size, flags | __GFP_ZERO);
+ return _kmalloc_noprof(size, flags | __GFP_ZERO, token);
}
+#define kzalloc_noprof(...) _kzalloc_noprof(__VA_ARGS__, __kmalloc_token(__VA_ARGS__))
#define kzalloc(...) alloc_hooks(kzalloc_noprof(__VA_ARGS__))
#define kzalloc_node(_size, _flags, _node) kmalloc_node(_size, (_flags)|__GFP_ZERO, _node)
-void *__kvmalloc_node_noprof(DECL_BUCKET_PARAMS(size, b), unsigned long align,
+void *__kvmalloc_node_noprof(DECL_KMALLOC_PARAMS(size, b, token), unsigned long align,
gfp_t flags, int node) __alloc_size(1);
#define kvmalloc_node_align_noprof(_size, _align, _flags, _node) \
- __kvmalloc_node_noprof(PASS_BUCKET_PARAMS(_size, NULL), _align, _flags, _node)
+ __kvmalloc_node_noprof(PASS_KMALLOC_PARAMS(_size, NULL, __kmalloc_token(_size)), _align, _flags, _node)
#define kvmalloc_node_align(...) \
alloc_hooks(kvmalloc_node_align_noprof(__VA_ARGS__))
#define kvmalloc_node(_s, _f, _n) kvmalloc_node_align(_s, 1, _f, _n)
+#define kvmalloc_node_noprof(size, flags, node) \
+ kvmalloc_node_align_noprof(size, 1, flags, node)
#define kvmalloc(...) kvmalloc_node(__VA_ARGS__, NUMA_NO_NODE)
+#define kvmalloc_noprof(_size, _flags) kvmalloc_node_noprof(_size, _flags, NUMA_NO_NODE)
#define kvzalloc(_size, _flags) kvmalloc(_size, (_flags)|__GFP_ZERO)
#define kvzalloc_node(_size, _flags, _node) kvmalloc_node(_size, (_flags)|__GFP_ZERO, _node)
#define kmem_buckets_valloc(_b, _size, _flags) \
- alloc_hooks(__kvmalloc_node_noprof(PASS_BUCKET_PARAMS(_size, _b), 1, _flags, NUMA_NO_NODE))
+ alloc_hooks(__kvmalloc_node_noprof(PASS_KMALLOC_PARAMS(_size, _b, __kmalloc_token(_size)), 1, _flags, NUMA_NO_NODE))
static inline __alloc_size(1, 2) void *
-kvmalloc_array_node_noprof(size_t n, size_t size, gfp_t flags, int node)
+_kvmalloc_array_node_noprof(size_t n, size_t size, gfp_t flags, int node, kmalloc_token_t token)
{
size_t bytes;
if (unlikely(check_mul_overflow(n, size, &bytes)))
return NULL;
- return kvmalloc_node_align_noprof(bytes, 1, flags, node);
+ return __kvmalloc_node_noprof(PASS_KMALLOC_PARAMS(bytes, NULL, token), 1, flags, node);
}
-
+#define kvmalloc_array_node_noprof(...) _kvmalloc_array_node_noprof(__VA_ARGS__, __kmalloc_token(__VA_ARGS__))
#define kvmalloc_array_noprof(...) kvmalloc_array_node_noprof(__VA_ARGS__, NUMA_NO_NODE)
#define kvcalloc_node_noprof(_n,_s,_f,_node) kvmalloc_array_node_noprof(_n,_s,(_f)|__GFP_ZERO,_node)
#define kvcalloc_noprof(...) kvcalloc_node_noprof(__VA_ARGS__, NUMA_NO_NODE)
@@ -1224,10 +1264,10 @@ kvmalloc_array_node_noprof(size_t n, size_t size, gfp_t flags, int node)
#define kvcalloc_node(...) alloc_hooks(kvcalloc_node_noprof(__VA_ARGS__))
#define kvcalloc(...) alloc_hooks(kvcalloc_noprof(__VA_ARGS__))
-void *kvrealloc_node_align_noprof(const void *p, size_t size, unsigned long align,
+void *kvrealloc_node_align_noprof(const void *p, DECL_TOKEN_PARAMS(size, token), unsigned long align,
gfp_t flags, int nid) __realloc_size(2);
-#define kvrealloc_node_align(...) \
- alloc_hooks(kvrealloc_node_align_noprof(__VA_ARGS__))
+#define kvrealloc_node_align(_p, _s, _a, _f, _n) \
+ alloc_hooks(kvrealloc_node_align_noprof(_p, PASS_TOKEN_PARAMS(_s, __kmalloc_token(_s)), _a, _f, _n))
#define kvrealloc_node(_p, _s, _f, _n) kvrealloc_node_align(_p, _s, 1, _f, _n)
#define kvrealloc(...) kvrealloc_node(__VA_ARGS__, NUMA_NO_NODE)
diff --git a/init/Kconfig b/init/Kconfig
index 2937c4d308ae..dba97bc8e2ce 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -170,6 +170,9 @@ config CC_HAS_BROKEN_COUNTED_BY_REF
# https://github.com/llvm/llvm-project/issues/182575
default y if CC_IS_CLANG && CLANG_VERSION < 220100
+config CC_HAS_ALLOC_TOKEN
+ def_bool $(cc-option,-falloc-token-max=123)
+
config CC_HAS_MULTIDIMENSIONAL_NONSTRING
def_bool $(success,echo 'char tag[][4] __attribute__((__nonstring__)) = { };' | $(CC) $(CLANG_FLAGS) -x c - -c -o /dev/null -Werror)
diff --git a/kernel/configs/hardening.config b/kernel/configs/hardening.config
index 7c3924614e01..26831a2a5739 100644
--- a/kernel/configs/hardening.config
+++ b/kernel/configs/hardening.config
@@ -22,7 +22,7 @@ CONFIG_SLAB_FREELIST_RANDOM=y
CONFIG_SLAB_FREELIST_HARDENED=y
CONFIG_SLAB_BUCKETS=y
CONFIG_SHUFFLE_PAGE_ALLOCATOR=y
-CONFIG_RANDOM_KMALLOC_CACHES=y
+CONFIG_KMALLOC_PARTITION_CACHES=y
# Sanity check userspace page table mappings.
CONFIG_PAGE_TABLE_CHECK=y
diff --git a/mm/Kconfig b/mm/Kconfig
index e8bf1e9e6ad9..4f187b07eb48 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -248,22 +248,75 @@ config SLUB_STATS
out which slabs are relevant to a particular load.
Try running: slabinfo -DA
-config RANDOM_KMALLOC_CACHES
- default n
+config KMALLOC_PARTITION_CACHES
depends on !SLUB_TINY
- bool "Randomize slab caches for normal kmalloc"
+ bool "Partitioned slab caches for normal kmalloc"
+ default RANDOM_KMALLOC_CACHES
help
- A hardening feature that creates multiple copies of slab caches for
- normal kmalloc allocation and makes kmalloc randomly pick one based
- on code address, which makes the attackers more difficult to spray
- vulnerable memory objects on the heap for the purpose of exploiting
- memory vulnerabilities.
+ A hardening feature that creates multiple isolated copies of slab
+ caches for normal kmalloc allocations. This makes it more difficult
+ to exploit memory-safety vulnerabilities by attacking vulnerable
+ co-located memory objects. Several modes are provided.
Currently the number of copies is set to 16, a reasonably large value
that effectively diverges the memory objects allocated for different
subsystems or modules into different caches, at the expense of a
- limited degree of memory and CPU overhead that relates to hardware and
- system workload.
+ limited degree of memory and CPU overhead that relates to hardware
+ and system workload.
+
+choice
+ prompt "Partitioned slab cache mode"
+ depends on KMALLOC_PARTITION_CACHES
+ default KMALLOC_PARTITION_TYPED if CC_HAS_ALLOC_TOKEN
+ default KMALLOC_PARTITION_RANDOM
+ help
+ Selects the slab cache partitioning mode.
+
+config KMALLOC_PARTITION_RANDOM
+ bool "Randomize slab caches for normal kmalloc"
+ help
+ Randomly pick a slab cache based on code address and a per-boot
+ random seed.
+
+ This makes it harder for attackers to predict object co-location.
+ The placement is random: while attackers don't know which kmalloc
+ cache an object will be allocated from, they might circumvent
+ the randomization by retrying attacks across multiple machines until
+ the target objects are co-located.
+
+config KMALLOC_PARTITION_TYPED
+ bool "Type based slab cache selection for normal kmalloc"
+ depends on CC_HAS_ALLOC_TOKEN
+ help
+ Rely on Clang's allocation tokens to choose a slab cache, where token
+ IDs are derived from the allocated type.
+
+ Unlike KMALLOC_PARTITION_RANDOM, cache assignment is deterministic based
+ on type, which guarantees that objects of certain types are not
+ placed in the same cache. This effectively mitigates certain classes
+ of exploits that probabilistic defenses like KMALLOC_PARTITION_RANDOM
+ only make harder but not impossible. However, this also means the
+ cache assignment is predictable.
+
+ Clang's default token ID calculation returns a bounded hash with
+ disjoint ranges for pointer-containing and pointerless objects: when
+ used as the slab cache index, this prevents buffer overflows on
+ primitive buffers from directly corrupting pointer-containing
+ objects.
+
+ The current effectiveness of Clang's type inference can be judged by
+ -Rpass=alloc-token, which provides diagnostics where (after dead-code
+ elimination) type inference failed.
+
+ Requires Clang 22 or later.
+
+endchoice
+
+config RANDOM_KMALLOC_CACHES
+ bool
+ transitional
+ help
+ Transitional config for migration to KMALLOC_PARTITION_CACHES.
endmenu # Slab allocator options
diff --git a/mm/kfence/kfence_test.c b/mm/kfence/kfence_test.c
index 5725a367246d..8807ea8ed0d3 100644
--- a/mm/kfence/kfence_test.c
+++ b/mm/kfence/kfence_test.c
@@ -214,7 +214,7 @@ static void test_cache_destroy(void)
static inline size_t kmalloc_cache_alignment(size_t size)
{
/* just to get ->align so no need to pass in the real caller */
- enum kmalloc_cache_type type = kmalloc_type(GFP_KERNEL, 0);
+ enum kmalloc_cache_type type = kmalloc_type(GFP_KERNEL, __kmalloc_token(0));
return kmalloc_caches[type][__kmalloc_index(size, false)]->align;
}
@@ -285,7 +285,7 @@ static void *test_alloc(struct kunit *test, size_t size, gfp_t gfp, enum allocat
if (is_kfence_address(alloc)) {
struct slab *slab = virt_to_slab(alloc);
- enum kmalloc_cache_type type = kmalloc_type(GFP_KERNEL, _RET_IP_);
+ enum kmalloc_cache_type type = kmalloc_type(GFP_KERNEL, __kmalloc_token(size));
struct kmem_cache *s = test_cache ?:
kmalloc_caches[type][__kmalloc_index(size, false)];
diff --git a/mm/slab.h b/mm/slab.h
index bf2f87acf5e3..1bf9c3021ae3 100644
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -362,12 +362,12 @@ static inline unsigned int size_index_elem(unsigned int bytes)
* KMALLOC_MAX_CACHE_SIZE and the caller must check that.
*/
static inline struct kmem_cache *
-kmalloc_slab(size_t size, kmem_buckets *b, gfp_t flags, unsigned long caller)
+kmalloc_slab(size_t size, kmem_buckets *b, gfp_t flags, kmalloc_token_t token)
{
unsigned int index;
if (!b)
- b = &kmalloc_caches[kmalloc_type(flags, caller)];
+ b = &kmalloc_caches[kmalloc_type(flags, token)];
if (size <= 192)
index = kmalloc_size_index[size_index_elem(size)];
else
diff --git a/mm/slab_common.c b/mm/slab_common.c
index d5a70a831a2a..388eb5980859 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -742,7 +742,7 @@ kmem_buckets kmalloc_caches[NR_KMALLOC_TYPES] __ro_after_init =
{ /* initialization for https://llvm.org/pr42570 */ };
EXPORT_SYMBOL(kmalloc_caches);
-#ifdef CONFIG_RANDOM_KMALLOC_CACHES
+#ifdef CONFIG_KMALLOC_PARTITION_RANDOM
unsigned long random_kmalloc_seed __ro_after_init;
EXPORT_SYMBOL(random_kmalloc_seed);
#endif
@@ -787,7 +787,7 @@ size_t kmalloc_size_roundup(size_t size)
* The flags don't matter since size_index is common to all.
* Neither does the caller for just getting ->object_size.
*/
- return kmalloc_slab(size, NULL, GFP_KERNEL, 0)->object_size;
+ return kmalloc_slab(size, NULL, GFP_KERNEL, __kmalloc_token(0))->object_size;
}
/* Above the smaller buckets, size is a multiple of page size. */
@@ -821,26 +821,26 @@ EXPORT_SYMBOL(kmalloc_size_roundup);
#define KMALLOC_RCL_NAME(sz)
#endif
-#ifdef CONFIG_RANDOM_KMALLOC_CACHES
-#define __KMALLOC_RANDOM_CONCAT(a, b) a ## b
-#define KMALLOC_RANDOM_NAME(N, sz) __KMALLOC_RANDOM_CONCAT(KMA_RAND_, N)(sz)
-#define KMA_RAND_1(sz) .name[KMALLOC_RANDOM_START + 1] = "kmalloc-rnd-01-" #sz,
-#define KMA_RAND_2(sz) KMA_RAND_1(sz) .name[KMALLOC_RANDOM_START + 2] = "kmalloc-rnd-02-" #sz,
-#define KMA_RAND_3(sz) KMA_RAND_2(sz) .name[KMALLOC_RANDOM_START + 3] = "kmalloc-rnd-03-" #sz,
-#define KMA_RAND_4(sz) KMA_RAND_3(sz) .name[KMALLOC_RANDOM_START + 4] = "kmalloc-rnd-04-" #sz,
-#define KMA_RAND_5(sz) KMA_RAND_4(sz) .name[KMALLOC_RANDOM_START + 5] = "kmalloc-rnd-05-" #sz,
-#define KMA_RAND_6(sz) KMA_RAND_5(sz) .name[KMALLOC_RANDOM_START + 6] = "kmalloc-rnd-06-" #sz,
-#define KMA_RAND_7(sz) KMA_RAND_6(sz) .name[KMALLOC_RANDOM_START + 7] = "kmalloc-rnd-07-" #sz,
-#define KMA_RAND_8(sz) KMA_RAND_7(sz) .name[KMALLOC_RANDOM_START + 8] = "kmalloc-rnd-08-" #sz,
-#define KMA_RAND_9(sz) KMA_RAND_8(sz) .name[KMALLOC_RANDOM_START + 9] = "kmalloc-rnd-09-" #sz,
-#define KMA_RAND_10(sz) KMA_RAND_9(sz) .name[KMALLOC_RANDOM_START + 10] = "kmalloc-rnd-10-" #sz,
-#define KMA_RAND_11(sz) KMA_RAND_10(sz) .name[KMALLOC_RANDOM_START + 11] = "kmalloc-rnd-11-" #sz,
-#define KMA_RAND_12(sz) KMA_RAND_11(sz) .name[KMALLOC_RANDOM_START + 12] = "kmalloc-rnd-12-" #sz,
-#define KMA_RAND_13(sz) KMA_RAND_12(sz) .name[KMALLOC_RANDOM_START + 13] = "kmalloc-rnd-13-" #sz,
-#define KMA_RAND_14(sz) KMA_RAND_13(sz) .name[KMALLOC_RANDOM_START + 14] = "kmalloc-rnd-14-" #sz,
-#define KMA_RAND_15(sz) KMA_RAND_14(sz) .name[KMALLOC_RANDOM_START + 15] = "kmalloc-rnd-15-" #sz,
-#else // CONFIG_RANDOM_KMALLOC_CACHES
-#define KMALLOC_RANDOM_NAME(N, sz)
+#ifdef CONFIG_KMALLOC_PARTITION_CACHES
+#define __KMALLOC_PARTITION_CONCAT(a, b) a ## b
+#define KMALLOC_PARTITION_NAME(N, sz) __KMALLOC_PARTITION_CONCAT(KMA_PART_, N)(sz)
+#define KMA_PART_1(sz) .name[KMALLOC_PARTITION_START + 1] = "kmalloc-part-01-" #sz,
+#define KMA_PART_2(sz) KMA_PART_1(sz) .name[KMALLOC_PARTITION_START + 2] = "kmalloc-part-02-" #sz,
+#define KMA_PART_3(sz) KMA_PART_2(sz) .name[KMALLOC_PARTITION_START + 3] = "kmalloc-part-03-" #sz,
+#define KMA_PART_4(sz) KMA_PART_3(sz) .name[KMALLOC_PARTITION_START + 4] = "kmalloc-part-04-" #sz,
+#define KMA_PART_5(sz) KMA_PART_4(sz) .name[KMALLOC_PARTITION_START + 5] = "kmalloc-part-05-" #sz,
+#define KMA_PART_6(sz) KMA_PART_5(sz) .name[KMALLOC_PARTITION_START + 6] = "kmalloc-part-06-" #sz,
+#define KMA_PART_7(sz) KMA_PART_6(sz) .name[KMALLOC_PARTITION_START + 7] = "kmalloc-part-07-" #sz,
+#define KMA_PART_8(sz) KMA_PART_7(sz) .name[KMALLOC_PARTITION_START + 8] = "kmalloc-part-08-" #sz,
+#define KMA_PART_9(sz) KMA_PART_8(sz) .name[KMALLOC_PARTITION_START + 9] = "kmalloc-part-09-" #sz,
+#define KMA_PART_10(sz) KMA_PART_9(sz) .name[KMALLOC_PARTITION_START + 10] = "kmalloc-part-10-" #sz,
+#define KMA_PART_11(sz) KMA_PART_10(sz) .name[KMALLOC_PARTITION_START + 11] = "kmalloc-part-11-" #sz,
+#define KMA_PART_12(sz) KMA_PART_11(sz) .name[KMALLOC_PARTITION_START + 12] = "kmalloc-part-12-" #sz,
+#define KMA_PART_13(sz) KMA_PART_12(sz) .name[KMALLOC_PARTITION_START + 13] = "kmalloc-part-13-" #sz,
+#define KMA_PART_14(sz) KMA_PART_13(sz) .name[KMALLOC_PARTITION_START + 14] = "kmalloc-part-14-" #sz,
+#define KMA_PART_15(sz) KMA_PART_14(sz) .name[KMALLOC_PARTITION_START + 15] = "kmalloc-part-15-" #sz,
+#else // CONFIG_KMALLOC_PARTITION_CACHES
+#define KMALLOC_PARTITION_NAME(N, sz)
#endif
#define INIT_KMALLOC_INFO(__size, __short_size) \
@@ -849,7 +849,7 @@ EXPORT_SYMBOL(kmalloc_size_roundup);
KMALLOC_RCL_NAME(__short_size) \
KMALLOC_CGROUP_NAME(__short_size) \
KMALLOC_DMA_NAME(__short_size) \
- KMALLOC_RANDOM_NAME(RANDOM_KMALLOC_CACHES_NR, __short_size) \
+ KMALLOC_PARTITION_NAME(KMALLOC_PARTITION_CACHES_NR, __short_size) \
.size = __size, \
}
@@ -961,8 +961,8 @@ new_kmalloc_cache(int idx, enum kmalloc_cache_type type)
flags |= SLAB_CACHE_DMA;
}
-#ifdef CONFIG_RANDOM_KMALLOC_CACHES
- if (type >= KMALLOC_RANDOM_START && type <= KMALLOC_RANDOM_END)
+#ifdef CONFIG_KMALLOC_PARTITION_CACHES
+ if (type >= KMALLOC_PARTITION_START && type <= KMALLOC_PARTITION_END)
flags |= SLAB_NO_MERGE;
#endif
@@ -1010,7 +1010,7 @@ void __init create_kmalloc_caches(void)
for (i = KMALLOC_SHIFT_LOW; i <= KMALLOC_SHIFT_HIGH; i++)
new_kmalloc_cache(i, type);
}
-#ifdef CONFIG_RANDOM_KMALLOC_CACHES
+#ifdef CONFIG_KMALLOC_PARTITION_RANDOM
random_kmalloc_seed = get_random_u64();
#endif
diff --git a/mm/slub.c b/mm/slub.c
index 161079ac5ba1..ccb208cfbecd 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -2129,11 +2129,11 @@ static inline size_t obj_exts_alloc_size(struct kmem_cache *s,
if (!is_kmalloc_normal(s))
return sz;
- obj_exts_cache = kmalloc_slab(sz, NULL, gfp, 0);
+ obj_exts_cache = kmalloc_slab(sz, NULL, gfp, __kmalloc_token(0));
/*
- * We can't simply compare s with obj_exts_cache, because random kmalloc
- * caches have multiple caches per size, selected by caller address.
- * Since caller address may differ between kmalloc_slab() and actual
+ * We can't simply compare s with obj_exts_cache, because partitioned kmalloc
+ * caches have multiple caches per size, selected by caller address or type.
+ * Since caller address or type may differ between kmalloc_slab() and actual
* allocation, bump size when sizes are equal.
*/
if (s->object_size == obj_exts_cache->object_size)
@@ -5274,7 +5274,7 @@ EXPORT_SYMBOL(__kmalloc_large_node_noprof);
static __always_inline
void *__do_kmalloc_node(size_t size, kmem_buckets *b, gfp_t flags, int node,
- unsigned long caller)
+ unsigned long caller, kmalloc_token_t token)
{
struct kmem_cache *s;
void *ret;
@@ -5289,22 +5289,24 @@ void *__do_kmalloc_node(size_t size, kmem_buckets *b, gfp_t flags, int node,
if (unlikely(!size))
return ZERO_SIZE_PTR;
- s = kmalloc_slab(size, b, flags, caller);
+ s = kmalloc_slab(size, b, flags, token);
ret = slab_alloc_node(s, NULL, flags, node, caller, size);
ret = kasan_kmalloc(s, ret, size, flags);
trace_kmalloc(caller, ret, size, s->size, flags, node);
return ret;
}
-void *__kmalloc_node_noprof(DECL_BUCKET_PARAMS(size, b), gfp_t flags, int node)
+void *__kmalloc_node_noprof(DECL_KMALLOC_PARAMS(size, b, token), gfp_t flags, int node)
{
- return __do_kmalloc_node(size, PASS_BUCKET_PARAM(b), flags, node, _RET_IP_);
+ return __do_kmalloc_node(size, PASS_BUCKET_PARAM(b), flags, node,
+ _RET_IP_, PASS_TOKEN_PARAM(token));
}
EXPORT_SYMBOL(__kmalloc_node_noprof);
-void *__kmalloc_noprof(size_t size, gfp_t flags)
+void *__kmalloc_noprof(DECL_KMALLOC_PARAMS(size, b, token), gfp_t flags)
{
- return __do_kmalloc_node(size, NULL, flags, NUMA_NO_NODE, _RET_IP_);
+ return __do_kmalloc_node(size, PASS_BUCKET_PARAM(b), flags,
+ NUMA_NO_NODE, _RET_IP_, PASS_TOKEN_PARAM(token));
}
EXPORT_SYMBOL(__kmalloc_noprof);
@@ -5319,7 +5321,7 @@ EXPORT_SYMBOL(__kmalloc_noprof);
* NULL does not mean EBUSY or EAGAIN. It means ENOMEM.
* There is no reason to call it again and expect !NULL.
*/
-void *kmalloc_nolock_noprof(size_t size, gfp_t gfp_flags, int node)
+void *_kmalloc_nolock_noprof(DECL_TOKEN_PARAMS(size, token), gfp_t gfp_flags, int node)
{
gfp_t alloc_gfp = __GFP_NOWARN | __GFP_NOMEMALLOC | gfp_flags;
struct kmem_cache *s;
@@ -5342,7 +5344,7 @@ void *kmalloc_nolock_noprof(size_t size, gfp_t gfp_flags, int node)
retry:
if (unlikely(size > KMALLOC_MAX_CACHE_SIZE))
return NULL;
- s = kmalloc_slab(size, NULL, alloc_gfp, _RET_IP_);
+ s = kmalloc_slab(size, NULL, alloc_gfp, PASS_TOKEN_PARAM(token));
if (!(s->flags & __CMPXCHG_DOUBLE) && !kmem_cache_debug(s))
/*
@@ -5395,12 +5397,13 @@ void *kmalloc_nolock_noprof(size_t size, gfp_t gfp_flags, int node)
ret = kasan_kmalloc(s, ret, size, alloc_gfp);
return ret;
}
-EXPORT_SYMBOL_GPL(kmalloc_nolock_noprof);
+EXPORT_SYMBOL_GPL(_kmalloc_nolock_noprof);
-void *__kmalloc_node_track_caller_noprof(DECL_BUCKET_PARAMS(size, b), gfp_t flags,
+void *__kmalloc_node_track_caller_noprof(DECL_KMALLOC_PARAMS(size, b, token), gfp_t flags,
int node, unsigned long caller)
{
- return __do_kmalloc_node(size, PASS_BUCKET_PARAM(b), flags, node, caller);
+ return __do_kmalloc_node(size, PASS_BUCKET_PARAM(b), flags, node,
+ caller, PASS_TOKEN_PARAM(token));
}
EXPORT_SYMBOL(__kmalloc_node_track_caller_noprof);
@@ -6631,7 +6634,7 @@ void kfree_nolock(const void *object)
EXPORT_SYMBOL_GPL(kfree_nolock);
static __always_inline __realloc_size(2) void *
-__do_krealloc(const void *p, size_t new_size, unsigned long align, gfp_t flags, int nid)
+__do_krealloc(const void *p, size_t new_size, unsigned long align, gfp_t flags, int nid, kmalloc_token_t token)
{
void *ret;
size_t ks = 0;
@@ -6703,7 +6706,7 @@ __do_krealloc(const void *p, size_t new_size, unsigned long align, gfp_t flags,
return (void *)p;
alloc_new:
- ret = kmalloc_node_track_caller_noprof(new_size, flags, nid, _RET_IP_);
+ ret = __kmalloc_node_track_caller_noprof(PASS_KMALLOC_PARAMS(new_size, NULL, token), flags, nid, _RET_IP_);
if (ret && p) {
/* Disable KASAN checks as the object's redzone is accessed. */
kasan_disable_current();
@@ -6752,7 +6755,7 @@ __do_krealloc(const void *p, size_t new_size, unsigned long align, gfp_t flags,
*
* Return: pointer to the allocated memory or %NULL in case of error
*/
-void *krealloc_node_align_noprof(const void *p, size_t new_size, unsigned long align,
+void *krealloc_node_align_noprof(const void *p, DECL_TOKEN_PARAMS(new_size, token), unsigned long align,
gfp_t flags, int nid)
{
void *ret;
@@ -6762,7 +6765,7 @@ void *krealloc_node_align_noprof(const void *p, size_t new_size, unsigned long a
return ZERO_SIZE_PTR;
}
- ret = __do_krealloc(p, new_size, align, flags, nid);
+ ret = __do_krealloc(p, new_size, align, flags, nid, PASS_TOKEN_PARAM(token));
if (ret && kasan_reset_tag(p) != kasan_reset_tag(ret))
kfree(p);
@@ -6799,6 +6802,7 @@ static gfp_t kmalloc_gfp_adjust(gfp_t flags, size_t size)
* failure, fall back to non-contiguous (vmalloc) allocation.
* @size: size of the request.
* @b: which set of kmalloc buckets to allocate from.
+ * @token: allocation token.
* @align: desired alignment.
* @flags: gfp mask for the allocation - must be compatible (superset) with GFP_KERNEL.
* @node: numa node to allocate from
@@ -6815,7 +6819,7 @@ static gfp_t kmalloc_gfp_adjust(gfp_t flags, size_t size)
*
* Return: pointer to the allocated memory of %NULL in case of failure
*/
-void *__kvmalloc_node_noprof(DECL_BUCKET_PARAMS(size, b), unsigned long align,
+void *__kvmalloc_node_noprof(DECL_KMALLOC_PARAMS(size, b, token), unsigned long align,
gfp_t flags, int node)
{
bool allow_block;
@@ -6827,7 +6831,7 @@ void *__kvmalloc_node_noprof(DECL_BUCKET_PARAMS(size, b), unsigned long align,
*/
ret = __do_kmalloc_node(size, PASS_BUCKET_PARAM(b),
kmalloc_gfp_adjust(flags, size),
- node, _RET_IP_);
+ node, _RET_IP_, PASS_TOKEN_PARAM(token));
if (ret || size <= PAGE_SIZE)
return ret;
@@ -6923,7 +6927,7 @@ EXPORT_SYMBOL(kvfree_sensitive);
*
* Return: pointer to the allocated memory or %NULL in case of error
*/
-void *kvrealloc_node_align_noprof(const void *p, size_t size, unsigned long align,
+void *kvrealloc_node_align_noprof(const void *p, DECL_TOKEN_PARAMS(size, token), unsigned long align,
gfp_t flags, int nid)
{
void *n;
@@ -6931,10 +6935,10 @@ void *kvrealloc_node_align_noprof(const void *p, size_t size, unsigned long alig
if (is_vmalloc_addr(p))
return vrealloc_node_align_noprof(p, size, align, flags, nid);
- n = krealloc_node_align_noprof(p, size, align, kmalloc_gfp_adjust(flags, size), nid);
+ n = krealloc_node_align_noprof(p, PASS_TOKEN_PARAMS(size, token), align, kmalloc_gfp_adjust(flags, size), nid);
if (!n) {
/* We failed to krealloc(), fall back to kvmalloc(). */
- n = kvmalloc_node_align_noprof(size, align, flags, nid);
+ n = __kvmalloc_node_noprof(PASS_KMALLOC_PARAMS(size, NULL, token), align, flags, nid);
if (!n)
return NULL;
@@ -8449,7 +8453,7 @@ static void __init bootstrap_kmalloc_sheaves(void)
{
enum kmalloc_cache_type type;
- for (type = KMALLOC_NORMAL; type <= KMALLOC_RANDOM_END; type++) {
+ for (type = KMALLOC_NORMAL; type <= KMALLOC_PARTITION_END; type++) {
for (int idx = 0; idx < KMALLOC_SHIFT_HIGH + 1; idx++) {
if (kmalloc_caches[type][idx])
bootstrap_cache_sheaves(kmalloc_caches[type][idx]);
--
2.54.0.545.g6539524ca2-goog
^ permalink raw reply related [flat|nested] 2+ messages in thread* [PATCH v3 2/2] slab: fix kernel-docs for mm-api
2026-04-24 13:24 [PATCH v3 1/2] slab: support for compiler-assisted type-based slab cache partitioning Marco Elver
@ 2026-04-24 13:24 ` Marco Elver
0 siblings, 0 replies; 2+ messages in thread
From: Marco Elver @ 2026-04-24 13:24 UTC (permalink / raw)
To: elver, Vlastimil Babka, Andrew Morton
Cc: Nathan Chancellor, Nicolas Schier, Dennis Zhou, Tejun Heo,
Christoph Lameter, Harry Yoo, Hao Li, David Rientjes,
Roman Gushchin, Kees Cook, Gustavo A. R. Silva, David Hildenbrand,
Lorenzo Stoakes, Liam R. Howlett, Mike Rapoport,
Suren Baghdasaryan, Michal Hocko, Alexander Potapenko,
Dmitry Vyukov, Nick Desaulniers, Bill Wendling, Justin Stitt,
Miguel Ojeda, linux-kbuild, linux-kernel, linux-mm,
linux-hardening, kasan-dev, llvm
The mm-api kernel-doc comments have been broken for a while, as many
documented symbols shifted from being direct function definitions to
macros wrapping _noprof implementations during the introduction of
allocation tagging (starting with commit 7bd230a26648 "mm/slab: enable
slab allocation tagging for kmalloc and friends").
When the kernel-doc block remains above the internal implementation
function but uses the public API name, the documentation generator fails
to associate the documented symbol and generates warnings and fails to
emit the documentation.
Fix this by:
1. Moving the kernel-doc comment blocks from slub.c to slab.h, placing
them directly above the user-facing macros.
2. Converting the variadic macros for the documented APIs to use
explicit arguments.
No functional change intended.
Signed-off-by: Marco Elver <elver@google.com>
---
include/linux/slab.h | 192 ++++++++++++++++++++++++++++++++-----------
mm/slub.c | 98 ----------------------
2 files changed, 144 insertions(+), 146 deletions(-)
diff --git a/include/linux/slab.h b/include/linux/slab.h
index c232f8a10af6..dcff0da1c01c 100644
--- a/include/linux/slab.h
+++ b/include/linux/slab.h
@@ -530,7 +530,46 @@ void * __must_check krealloc_node_align_noprof(const void *objp,
unsigned long align,
gfp_t flags, int nid) __realloc_size(2);
#define krealloc_noprof(_o, _s, _f) krealloc_node_align_noprof(_o, PASS_TOKEN_PARAMS(_s, __kmalloc_token(_s)), 1, _f, NUMA_NO_NODE)
-#define krealloc_node_align(_o, _s, _a, _f, _n) alloc_hooks(krealloc_node_align_noprof(_o, PASS_TOKEN_PARAMS(_s, __kmalloc_token(_s)), _a, _f, _n))
+/**
+ * krealloc_node_align - reallocate memory. The contents will remain unchanged.
+ * @p: object to reallocate memory for.
+ * @new_size: how many bytes of memory are required.
+ * @align: desired alignment.
+ * @flags: the type of memory to allocate.
+ * @nid: NUMA node or NUMA_NO_NODE
+ *
+ * If @p is %NULL, krealloc() behaves exactly like kmalloc(). If @new_size
+ * is 0 and @p is not a %NULL pointer, the object pointed to is freed.
+ *
+ * Only alignments up to those guaranteed by kmalloc() will be honored. Please see
+ * Documentation/core-api/memory-allocation.rst for more details.
+ *
+ * If __GFP_ZERO logic is requested, callers must ensure that, starting with the
+ * initial memory allocation, every subsequent call to this API for the same
+ * memory allocation is flagged with __GFP_ZERO. Otherwise, it is possible that
+ * __GFP_ZERO is not fully honored by this API.
+ *
+ * When slub_debug_orig_size() is off, krealloc() only knows about the bucket
+ * size of an allocation (but not the exact size it was allocated with) and
+ * hence implements the following semantics for shrinking and growing buffers
+ * with __GFP_ZERO::
+ *
+ * new bucket
+ * 0 size size
+ * |--------|----------------|
+ * | keep | zero |
+ *
+ * Otherwise, the original allocation size 'orig_size' could be used to
+ * precisely clear the requested size, and the new size will also be stored
+ * as the new 'orig_size'.
+ *
+ * In any case, the contents of the object pointed to are preserved up to the
+ * lesser of the new and old sizes.
+ *
+ * Return: pointer to the allocated memory or %NULL in case of error
+ */
+#define krealloc_node_align(p, new_size, align, flags, nid) \
+ alloc_hooks(krealloc_node_align_noprof(p, PASS_TOKEN_PARAMS(new_size, __kmalloc_token(new_size)), align, flags, nid))
#define krealloc_node(_o, _s, _f, _n) krealloc_node_align(_o, _s, 1, _f, _n)
#define krealloc(...) krealloc_node(__VA_ARGS__, NUMA_NO_NODE)
@@ -913,6 +952,22 @@ void *__kmalloc_large_noprof(size_t size, gfp_t flags)
void *__kmalloc_large_node_noprof(size_t size, gfp_t flags, int node)
__assume_page_alignment __alloc_size(1);
+static __always_inline __alloc_size(1) void *_kmalloc_noprof(size_t size, gfp_t flags, kmalloc_token_t token)
+{
+ if (__builtin_constant_p(size) && size) {
+ unsigned int index;
+
+ if (size > KMALLOC_MAX_CACHE_SIZE)
+ return __kmalloc_large_noprof(size, flags);
+
+ index = kmalloc_index(size);
+ return __kmalloc_cache_noprof(
+ kmalloc_caches[kmalloc_type(flags, token)][index],
+ flags, size);
+ }
+ return __kmalloc_noprof(PASS_KMALLOC_PARAMS(size, NULL, token), flags);
+}
+#define kmalloc_noprof(...) _kmalloc_noprof(__VA_ARGS__, __kmalloc_token(__VA_ARGS__))
/**
* kmalloc - allocate kernel memory
* @size: how many bytes of memory are required.
@@ -968,27 +1023,22 @@ void *__kmalloc_large_node_noprof(size_t size, gfp_t flags, int node)
* Try really hard to succeed the allocation but fail
* eventually.
*/
-static __always_inline __alloc_size(1) void *_kmalloc_noprof(size_t size, gfp_t flags, kmalloc_token_t token)
-{
- if (__builtin_constant_p(size) && size) {
- unsigned int index;
-
- if (size > KMALLOC_MAX_CACHE_SIZE)
- return __kmalloc_large_noprof(size, flags);
-
- index = kmalloc_index(size);
- return __kmalloc_cache_noprof(
- kmalloc_caches[kmalloc_type(flags, token)][index],
- flags, size);
- }
- return __kmalloc_noprof(PASS_KMALLOC_PARAMS(size, NULL, token), flags);
-}
-#define kmalloc_noprof(...) _kmalloc_noprof(__VA_ARGS__, __kmalloc_token(__VA_ARGS__))
-#define kmalloc(...) alloc_hooks(kmalloc_noprof(__VA_ARGS__))
+#define kmalloc(size, flags) alloc_hooks(kmalloc_noprof(size, flags))
void *_kmalloc_nolock_noprof(DECL_TOKEN_PARAMS(size, token), gfp_t gfp_flags, int node);
#define kmalloc_nolock_noprof(_s, _f, _n) _kmalloc_nolock_noprof(PASS_TOKEN_PARAMS(_s, __kmalloc_token(_s)), _f, _n)
-#define kmalloc_nolock(...) alloc_hooks(kmalloc_nolock_noprof(__VA_ARGS__))
+/**
+ * kmalloc_nolock - Allocate an object of given size from any context.
+ * @size: size to allocate
+ * @gfp_flags: GFP flags. Only __GFP_ACCOUNT, __GFP_ZERO, __GFP_NO_OBJ_EXT
+ * allowed.
+ * @node: node number of the target node.
+ *
+ * Return: pointer to the new object or NULL in case of error.
+ * NULL does not mean EBUSY or EAGAIN. It means ENOMEM.
+ * There is no reason to call it again and expect !NULL.
+ */
+#define kmalloc_nolock(size, gfp_flags, node) alloc_hooks(kmalloc_nolock_noprof(size, gfp_flags, node))
/**
* __alloc_objs - Allocate objects of a given type using
@@ -1115,23 +1165,36 @@ static __always_inline __alloc_size(1) void *_kmalloc_node_noprof(size_t size, g
#define kmalloc_node_noprof(...) _kmalloc_node_noprof(__VA_ARGS__, __kmalloc_token(__VA_ARGS__))
#define kmalloc_node(...) alloc_hooks(kmalloc_node_noprof(__VA_ARGS__))
+static inline __alloc_size(1, 2) void *_kmalloc_array_noprof(size_t n, size_t size, gfp_t flags, kmalloc_token_t token)
+{
+ size_t bytes;
+
+ if (unlikely(check_mul_overflow(n, size, &bytes)))
+ return NULL;
+ return _kmalloc_noprof(bytes, flags, token);
+}
+#define kmalloc_array_noprof(...) _kmalloc_array_noprof(__VA_ARGS__, __kmalloc_token(__VA_ARGS__))
/**
* kmalloc_array - allocate memory for an array.
* @n: number of elements.
* @size: element size.
* @flags: the type of memory to allocate (see kmalloc).
*/
-static inline __alloc_size(1, 2) void *_kmalloc_array_noprof(size_t n, size_t size, gfp_t flags, kmalloc_token_t token)
+#define kmalloc_array(n, size, flags) alloc_hooks(kmalloc_array_noprof(n, size, flags))
+
+static inline __realloc_size(2, 3) void * __must_check _krealloc_array_noprof(void *p,
+ size_t new_n,
+ size_t new_size,
+ gfp_t flags, kmalloc_token_t token)
{
size_t bytes;
- if (unlikely(check_mul_overflow(n, size, &bytes)))
+ if (unlikely(check_mul_overflow(new_n, new_size, &bytes)))
return NULL;
- return _kmalloc_noprof(bytes, flags, token);
-}
-#define kmalloc_array_noprof(...) _kmalloc_array_noprof(__VA_ARGS__, __kmalloc_token(__VA_ARGS__))
-#define kmalloc_array(...) alloc_hooks(kmalloc_array_noprof(__VA_ARGS__))
+ return krealloc_node_align_noprof(p, PASS_TOKEN_PARAMS(bytes, token), 1, flags, NUMA_NO_NODE);
+}
+#define krealloc_array_noprof(...) _krealloc_array_noprof(__VA_ARGS__, __kmalloc_token(__VA_ARGS__))
/**
* krealloc_array - reallocate memory for an array.
* @p: pointer to the memory chunk to reallocate
@@ -1149,20 +1212,7 @@ static inline __alloc_size(1, 2) void *_kmalloc_array_noprof(size_t n, size_t si
* In any case, the contents of the object pointed to are preserved up to the
* lesser of the new and old sizes.
*/
-static inline __realloc_size(2, 3) void * __must_check _krealloc_array_noprof(void *p,
- size_t new_n,
- size_t new_size,
- gfp_t flags, kmalloc_token_t token)
-{
- size_t bytes;
-
- if (unlikely(check_mul_overflow(new_n, new_size, &bytes)))
- return NULL;
-
- return krealloc_node_align_noprof(p, PASS_TOKEN_PARAMS(bytes, token), 1, flags, NUMA_NO_NODE);
-}
-#define krealloc_array_noprof(...) _krealloc_array_noprof(__VA_ARGS__, __kmalloc_token(__VA_ARGS__))
-#define krealloc_array(...) alloc_hooks(krealloc_array_noprof(__VA_ARGS__))
+#define krealloc_array(p, new_n, new_size, flags) alloc_hooks(krealloc_array_noprof(p, new_n, new_size, flags))
/**
* kcalloc - allocate memory for an array. The memory is set to zero.
@@ -1214,17 +1264,17 @@ static inline __alloc_size(1, 2) void *_kmalloc_array_node_noprof(size_t n, size
*/
#define kmem_cache_zalloc(_k, _flags) kmem_cache_alloc(_k, (_flags)|__GFP_ZERO)
-/**
- * kzalloc - allocate memory. The memory is set to zero.
- * @size: how many bytes of memory are required.
- * @flags: the type of memory to allocate (see kmalloc).
- */
static inline __alloc_size(1) void *_kzalloc_noprof(size_t size, gfp_t flags, kmalloc_token_t token)
{
return _kmalloc_noprof(size, flags | __GFP_ZERO, token);
}
#define kzalloc_noprof(...) _kzalloc_noprof(__VA_ARGS__, __kmalloc_token(__VA_ARGS__))
-#define kzalloc(...) alloc_hooks(kzalloc_noprof(__VA_ARGS__))
+/**
+ * kzalloc - allocate memory. The memory is set to zero.
+ * @size: how many bytes of memory are required.
+ * @flags: the type of memory to allocate (see kmalloc).
+ */
+#define kzalloc(size, flags) alloc_hooks(kzalloc_noprof(size, flags))
#define kzalloc_node(_size, _flags, _node) kmalloc_node(_size, (_flags)|__GFP_ZERO, _node)
void *__kvmalloc_node_noprof(DECL_KMALLOC_PARAMS(size, b, token), unsigned long align,
@@ -1233,7 +1283,26 @@ void *__kvmalloc_node_noprof(DECL_KMALLOC_PARAMS(size, b, token), unsigned long
__kvmalloc_node_noprof(PASS_KMALLOC_PARAMS(_size, NULL, __kmalloc_token(_size)), _align, _flags, _node)
#define kvmalloc_node_align(...) \
alloc_hooks(kvmalloc_node_align_noprof(__VA_ARGS__))
-#define kvmalloc_node(_s, _f, _n) kvmalloc_node_align(_s, 1, _f, _n)
+/**
+ * kvmalloc_node - attempt to allocate physically contiguous memory, but upon
+ * failure, fall back to non-contiguous (vmalloc) allocation.
+ * @size: size of the request.
+ * @flags: gfp mask for the allocation - must be compatible (superset) with GFP_KERNEL.
+ * @node: numa node to allocate from
+ *
+ * Only alignments up to those guaranteed by kmalloc() will be honored. Please see
+ * Documentation/core-api/memory-allocation.rst for more details.
+ *
+ * Uses kmalloc to get the memory but if the allocation fails then falls back
+ * to the vmalloc allocator. Use kvfree for freeing the memory.
+ *
+ * GFP_NOWAIT and GFP_ATOMIC are supported, the __GFP_NORETRY modifier is not.
+ * __GFP_RETRY_MAYFAIL is supported, and it should be used only if kmalloc is
+ * preferable to the vmalloc fallback, due to visible performance drawbacks.
+ *
+ * Return: pointer to the allocated memory of %NULL in case of failure
+ */
+#define kvmalloc_node(size, flags, node) kvmalloc_node_align(size, 1, flags, node)
#define kvmalloc_node_noprof(size, flags, node) \
kvmalloc_node_align_noprof(size, 1, flags, node)
#define kvmalloc(...) kvmalloc_node(__VA_ARGS__, NUMA_NO_NODE)
@@ -1266,8 +1335,35 @@ _kvmalloc_array_node_noprof(size_t n, size_t size, gfp_t flags, int node, kmallo
void *kvrealloc_node_align_noprof(const void *p, DECL_TOKEN_PARAMS(size, token), unsigned long align,
gfp_t flags, int nid) __realloc_size(2);
-#define kvrealloc_node_align(_p, _s, _a, _f, _n) \
- alloc_hooks(kvrealloc_node_align_noprof(_p, PASS_TOKEN_PARAMS(_s, __kmalloc_token(_s)), _a, _f, _n))
+/**
+ * kvrealloc_node_align - reallocate memory; contents remain unchanged
+ * @p: object to reallocate memory for
+ * @size: the size to reallocate
+ * @align: desired alignment
+ * @flags: the flags for the page level allocator
+ * @nid: NUMA node id
+ *
+ * If @p is %NULL, kvrealloc() behaves exactly like kvmalloc(). If @size is 0
+ * and @p is not a %NULL pointer, the object pointed to is freed.
+ *
+ * Only alignments up to those guaranteed by kmalloc() will be honored. Please see
+ * Documentation/core-api/memory-allocation.rst for more details.
+ *
+ * If __GFP_ZERO logic is requested, callers must ensure that, starting with the
+ * initial memory allocation, every subsequent call to this API for the same
+ * memory allocation is flagged with __GFP_ZERO. Otherwise, it is possible that
+ * __GFP_ZERO is not fully honored by this API.
+ *
+ * In any case, the contents of the object pointed to are preserved up to the
+ * lesser of the new and old sizes.
+ *
+ * This function must not be called concurrently with itself or kvfree() for the
+ * same memory allocation.
+ *
+ * Return: pointer to the allocated memory or %NULL in case of error
+ */
+#define kvrealloc_node_align(p, size, align, flags, nid) \
+ alloc_hooks(kvrealloc_node_align_noprof(p, PASS_TOKEN_PARAMS(size, __kmalloc_token(size)), align, flags, nid))
#define kvrealloc_node(_p, _s, _f, _n) kvrealloc_node_align(_p, _s, 1, _f, _n)
#define kvrealloc(...) kvrealloc_node(__VA_ARGS__, NUMA_NO_NODE)
diff --git a/mm/slub.c b/mm/slub.c
index ccb208cfbecd..dbc3c947e5be 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -5310,17 +5310,6 @@ void *__kmalloc_noprof(DECL_KMALLOC_PARAMS(size, b, token), gfp_t flags)
}
EXPORT_SYMBOL(__kmalloc_noprof);
-/**
- * kmalloc_nolock - Allocate an object of given size from any context.
- * @size: size to allocate
- * @gfp_flags: GFP flags. Only __GFP_ACCOUNT, __GFP_ZERO, __GFP_NO_OBJ_EXT
- * allowed.
- * @node: node number of the target node.
- *
- * Return: pointer to the new object or NULL in case of error.
- * NULL does not mean EBUSY or EAGAIN. It means ENOMEM.
- * There is no reason to call it again and expect !NULL.
- */
void *_kmalloc_nolock_noprof(DECL_TOKEN_PARAMS(size, token), gfp_t gfp_flags, int node)
{
gfp_t alloc_gfp = __GFP_NOWARN | __GFP_NOMEMALLOC | gfp_flags;
@@ -6717,44 +6706,6 @@ __do_krealloc(const void *p, size_t new_size, unsigned long align, gfp_t flags,
return ret;
}
-/**
- * krealloc_node_align - reallocate memory. The contents will remain unchanged.
- * @p: object to reallocate memory for.
- * @new_size: how many bytes of memory are required.
- * @align: desired alignment.
- * @flags: the type of memory to allocate.
- * @nid: NUMA node or NUMA_NO_NODE
- *
- * If @p is %NULL, krealloc() behaves exactly like kmalloc(). If @new_size
- * is 0 and @p is not a %NULL pointer, the object pointed to is freed.
- *
- * Only alignments up to those guaranteed by kmalloc() will be honored. Please see
- * Documentation/core-api/memory-allocation.rst for more details.
- *
- * If __GFP_ZERO logic is requested, callers must ensure that, starting with the
- * initial memory allocation, every subsequent call to this API for the same
- * memory allocation is flagged with __GFP_ZERO. Otherwise, it is possible that
- * __GFP_ZERO is not fully honored by this API.
- *
- * When slub_debug_orig_size() is off, krealloc() only knows about the bucket
- * size of an allocation (but not the exact size it was allocated with) and
- * hence implements the following semantics for shrinking and growing buffers
- * with __GFP_ZERO::
- *
- * new bucket
- * 0 size size
- * |--------|----------------|
- * | keep | zero |
- *
- * Otherwise, the original allocation size 'orig_size' could be used to
- * precisely clear the requested size, and the new size will also be stored
- * as the new 'orig_size'.
- *
- * In any case, the contents of the object pointed to are preserved up to the
- * lesser of the new and old sizes.
- *
- * Return: pointer to the allocated memory or %NULL in case of error
- */
void *krealloc_node_align_noprof(const void *p, DECL_TOKEN_PARAMS(new_size, token), unsigned long align,
gfp_t flags, int nid)
{
@@ -6797,28 +6748,6 @@ static gfp_t kmalloc_gfp_adjust(gfp_t flags, size_t size)
return flags;
}
-/**
- * __kvmalloc_node - attempt to allocate physically contiguous memory, but upon
- * failure, fall back to non-contiguous (vmalloc) allocation.
- * @size: size of the request.
- * @b: which set of kmalloc buckets to allocate from.
- * @token: allocation token.
- * @align: desired alignment.
- * @flags: gfp mask for the allocation - must be compatible (superset) with GFP_KERNEL.
- * @node: numa node to allocate from
- *
- * Only alignments up to those guaranteed by kmalloc() will be honored. Please see
- * Documentation/core-api/memory-allocation.rst for more details.
- *
- * Uses kmalloc to get the memory but if the allocation fails then falls back
- * to the vmalloc allocator. Use kvfree for freeing the memory.
- *
- * GFP_NOWAIT and GFP_ATOMIC are supported, the __GFP_NORETRY modifier is not.
- * __GFP_RETRY_MAYFAIL is supported, and it should be used only if kmalloc is
- * preferable to the vmalloc fallback, due to visible performance drawbacks.
- *
- * Return: pointer to the allocated memory of %NULL in case of failure
- */
void *__kvmalloc_node_noprof(DECL_KMALLOC_PARAMS(size, b, token), unsigned long align,
gfp_t flags, int node)
{
@@ -6900,33 +6829,6 @@ void kvfree_sensitive(const void *addr, size_t len)
}
EXPORT_SYMBOL(kvfree_sensitive);
-/**
- * kvrealloc_node_align - reallocate memory; contents remain unchanged
- * @p: object to reallocate memory for
- * @size: the size to reallocate
- * @align: desired alignment
- * @flags: the flags for the page level allocator
- * @nid: NUMA node id
- *
- * If @p is %NULL, kvrealloc() behaves exactly like kvmalloc(). If @size is 0
- * and @p is not a %NULL pointer, the object pointed to is freed.
- *
- * Only alignments up to those guaranteed by kmalloc() will be honored. Please see
- * Documentation/core-api/memory-allocation.rst for more details.
- *
- * If __GFP_ZERO logic is requested, callers must ensure that, starting with the
- * initial memory allocation, every subsequent call to this API for the same
- * memory allocation is flagged with __GFP_ZERO. Otherwise, it is possible that
- * __GFP_ZERO is not fully honored by this API.
- *
- * In any case, the contents of the object pointed to are preserved up to the
- * lesser of the new and old sizes.
- *
- * This function must not be called concurrently with itself or kvfree() for the
- * same memory allocation.
- *
- * Return: pointer to the allocated memory or %NULL in case of error
- */
void *kvrealloc_node_align_noprof(const void *p, DECL_TOKEN_PARAMS(size, token), unsigned long align,
gfp_t flags, int nid)
{
--
2.54.0.545.g6539524ca2-goog
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2026-04-24 13:24 [PATCH v3 1/2] slab: support for compiler-assisted type-based slab cache partitioning Marco Elver
2026-04-24 13:24 ` [PATCH v3 2/2] slab: fix kernel-docs for mm-api Marco Elver
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