@@ -48,16 +48,6 @@ static int __init kaslr_init(void)
pr_info("KASLR enabled\n");
- /*
- * KASAN without KASAN_VMALLOC does not expect the module region to
- * intersect the vmalloc region, since shadow memory is allocated for
- * each module at load time, whereas the vmalloc region will already be
- * shadowed by KASAN zero pages.
- */
- BUILD_BUG_ON((IS_ENABLED(CONFIG_KASAN_GENERIC) ||
- IS_ENABLED(CONFIG_KASAN_SW_TAGS)) &&
- !IS_ENABLED(CONFIG_KASAN_VMALLOC));
-
seed = get_random_u32();
if (IS_ENABLED(CONFIG_RANDOMIZE_MODULE_REGION_FULL)) {
@@ -32,33 +32,16 @@ void *module_alloc(unsigned long size)
if (IS_ENABLED(CONFIG_ARM64_MODULE_PLTS))
gfp_mask |= __GFP_NOWARN;
- if (IS_ENABLED(CONFIG_KASAN_GENERIC) ||
- IS_ENABLED(CONFIG_KASAN_SW_TAGS))
- /* don't exceed the static module region - see below */
- module_alloc_end = MODULES_END;
-
p = __vmalloc_node_range(size, MODULE_ALIGN, module_alloc_base,
- module_alloc_end, gfp_mask, PAGE_KERNEL, VM_DEFER_KMEMLEAK,
+ module_alloc_end, gfp_mask, PAGE_KERNEL, 0,
NUMA_NO_NODE, __builtin_return_address(0));
- if (!p && IS_ENABLED(CONFIG_ARM64_MODULE_PLTS) &&
- (IS_ENABLED(CONFIG_KASAN_VMALLOC) ||
- (!IS_ENABLED(CONFIG_KASAN_GENERIC) &&
- !IS_ENABLED(CONFIG_KASAN_SW_TAGS))))
- /*
- * KASAN without KASAN_VMALLOC can only deal with module
- * allocations being served from the reserved module region,
- * since the remainder of the vmalloc region is already
- * backed by zero shadow pages, and punching holes into it
- * is non-trivial. Since the module region is not randomized
- * when KASAN is enabled without KASAN_VMALLOC, it is even
- * less likely that the module region gets exhausted, so we
- * can simply omit this fallback in that case.
- */
+ if (!p && IS_ENABLED(CONFIG_ARM64_MODULE_PLTS)) {
p = __vmalloc_node_range(size, MODULE_ALIGN, module_alloc_base,
module_alloc_base + SZ_2G, GFP_KERNEL,
PAGE_KERNEL, 0, NUMA_NO_NODE,
__builtin_return_address(0));
+ }
if (p && (kasan_alloc_module_shadow(p, size, gfp_mask) < 0)) {
vfree(p);
Historically, KASAN could be selected with or without KASAN_VMALLOC, and we had to be very careful where to place modules when KASAN_VMALLOC was not selected. However, since commit: f6f37d9320a11e90 ("arm64: select KASAN_VMALLOC for SW/HW_TAGS modes") Selecting CONFIG_KASAN on arm64 will also select CONFIG_KASAN_VMALLOC, and so the logic for handling CONFIG_KASAN without CONFIG_KASAN_VMALLOC is redundant and can be removed. Note: the "kasan.vmalloc={on,off}" option which only exists for HW_TAGS changes whether the vmalloc region is given non-match-all tags, and does not affect the page table manipulation code. The VM_DEFER_KMEMLEAK flag was only necessary for !CONFIG_KASAN_VMALLOC as described in its introduction in commit: 60115fa54ad7b913 ("mm: defer kmemleak object creation of module_alloc()") ... and therefore it can also be removed. Remove the redundant logic for !CONFIG_KASAN_VMALLOC. At the same time, add the missing braces around the multi-line conditional block in arch/arm64/kernel/module.c. Suggested-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Mark Rutland <mark.rutland@arm.com> Reviewed-by: Ard Biesheuvel <ardb@kernel.org> Cc: Alexander Potapenko <glider@google.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andrey Konovalov <andreyknvl@google.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Will Deacon <will@kernel.org> --- arch/arm64/kernel/kaslr.c | 10 ---------- arch/arm64/kernel/module.c | 23 +++-------------------- 2 files changed, 3 insertions(+), 30 deletions(-)