From 79357cd06d41d0f5a11b17d7c86176e395d10ef2 Mon Sep 17 00:00:00 2001 From: "Uladzislau Rezki (Sony)" Date: Sun, 31 Aug 2025 14:10:58 +0200 Subject: mm/vmalloc, mm/kasan: respect gfp mask in kasan_populate_vmalloc() kasan_populate_vmalloc() and its helpers ignore the caller's gfp_mask and always allocate memory using the hardcoded GFP_KERNEL flag. This makes them inconsistent with vmalloc(), which was recently extended to support GFP_NOFS and GFP_NOIO allocations. Page table allocations performed during shadow population also ignore the external gfp_mask. To preserve the intended semantics of GFP_NOFS and GFP_NOIO, wrap the apply_to_page_range() calls into the appropriate memalloc scope. xfs calls vmalloc with GFP_NOFS, so this bug could lead to deadlock. There was a report here https://lkml.kernel.org/r/686ea951.050a0220.385921.0016.GAE@google.com This patch: - Extends kasan_populate_vmalloc() and helpers to take gfp_mask; - Passes gfp_mask down to alloc_pages_bulk() and __get_free_page(); - Enforces GFP_NOFS/NOIO semantics with memalloc_*_save()/restore() around apply_to_page_range(); - Updates vmalloc.c and percpu allocator call sites accordingly. Link: https://lkml.kernel.org/r/20250831121058.92971-1-urezki@gmail.com Fixes: 451769ebb7e7 ("mm/vmalloc: alloc GFP_NO{FS,IO} for vmalloc") Signed-off-by: Uladzislau Rezki (Sony) Reported-by: syzbot+3470c9ffee63e4abafeb@syzkaller.appspotmail.com Reviewed-by: Andrey Ryabinin Cc: Baoquan He Cc: Michal Hocko Cc: Alexander Potapenko Cc: Andrey Konovalov Cc: Dmitry Vyukov Cc: Vincenzo Frascino Cc: Signed-off-by: Andrew Morton --- include/linux/kasan.h | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'include/linux') diff --git a/include/linux/kasan.h b/include/linux/kasan.h index 890011071f2b..fe5ce9215821 100644 --- a/include/linux/kasan.h +++ b/include/linux/kasan.h @@ -562,7 +562,7 @@ static inline void kasan_init_hw_tags(void) { } #if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS) void kasan_populate_early_vm_area_shadow(void *start, unsigned long size); -int kasan_populate_vmalloc(unsigned long addr, unsigned long size); +int kasan_populate_vmalloc(unsigned long addr, unsigned long size, gfp_t gfp_mask); void kasan_release_vmalloc(unsigned long start, unsigned long end, unsigned long free_region_start, unsigned long free_region_end, @@ -574,7 +574,7 @@ static inline void kasan_populate_early_vm_area_shadow(void *start, unsigned long size) { } static inline int kasan_populate_vmalloc(unsigned long start, - unsigned long size) + unsigned long size, gfp_t gfp_mask) { return 0; } @@ -610,7 +610,7 @@ static __always_inline void kasan_poison_vmalloc(const void *start, static inline void kasan_populate_early_vm_area_shadow(void *start, unsigned long size) { } static inline int kasan_populate_vmalloc(unsigned long start, - unsigned long size) + unsigned long size, gfp_t gfp_mask) { return 0; } -- cgit v1.2.3 From 3fac212fe489aa0dbe8d80a42a7809840ca7b0f9 Mon Sep 17 00:00:00 2001 From: Nathan Chancellor Date: Tue, 2 Sep 2025 15:49:26 -0700 Subject: compiler-clang.h: define __SANITIZE_*__ macros only when undefined Clang 22 recently added support for defining __SANITIZE__ macros similar to GCC [1], which causes warnings (or errors with CONFIG_WERROR=y or W=e) with the existing defines that the kernel creates to emulate this behavior with existing clang versions. In file included from :3: In file included from include/linux/compiler_types.h:171: include/linux/compiler-clang.h:37:9: error: '__SANITIZE_THREAD__' macro redefined [-Werror,-Wmacro-redefined] 37 | #define __SANITIZE_THREAD__ | ^ :352:9: note: previous definition is here 352 | #define __SANITIZE_THREAD__ 1 | ^ Refactor compiler-clang.h to only define the sanitizer macros when they are undefined and adjust the rest of the code to use these macros for checking if the sanitizers are enabled, clearing up the warnings and allowing the kernel to easily drop these defines when the minimum supported version of LLVM for building the kernel becomes 22.0.0 or newer. Link: https://lkml.kernel.org/r/20250902-clang-update-sanitize-defines-v1-1-cf3702ca3d92@kernel.org Link: https://github.com/llvm/llvm-project/commit/568c23bbd3303518c5056d7f03444dae4fdc8a9c [1] Signed-off-by: Nathan Chancellor Reviewed-by: Justin Stitt Cc: Alexander Potapenko Cc: Andrey Konovalov Cc: Andrey Ryabinin Cc: Bill Wendling Cc: Dmitriy Vyukov Cc: Marco Elver Cc: Signed-off-by: Andrew Morton --- include/linux/compiler-clang.h | 29 ++++++++++++++++++++++++----- 1 file changed, 24 insertions(+), 5 deletions(-) (limited to 'include/linux') diff --git a/include/linux/compiler-clang.h b/include/linux/compiler-clang.h index fa4ffe037bc7..8720a0705900 100644 --- a/include/linux/compiler-clang.h +++ b/include/linux/compiler-clang.h @@ -18,23 +18,42 @@ #define KASAN_ABI_VERSION 5 /* + * Clang 22 added preprocessor macros to match GCC, in hopes of eventually + * dropping __has_feature support for sanitizers: + * https://github.com/llvm/llvm-project/commit/568c23bbd3303518c5056d7f03444dae4fdc8a9c + * Create these macros for older versions of clang so that it is easy to clean + * up once the minimum supported version of LLVM for building the kernel always + * creates these macros. + * * Note: Checking __has_feature(*_sanitizer) is only true if the feature is * enabled. Therefore it is not required to additionally check defined(CONFIG_*) * to avoid adding redundant attributes in other configurations. */ +#if __has_feature(address_sanitizer) && !defined(__SANITIZE_ADDRESS__) +#define __SANITIZE_ADDRESS__ +#endif +#if __has_feature(hwaddress_sanitizer) && !defined(__SANITIZE_HWADDRESS__) +#define __SANITIZE_HWADDRESS__ +#endif +#if __has_feature(thread_sanitizer) && !defined(__SANITIZE_THREAD__) +#define __SANITIZE_THREAD__ +#endif -#if __has_feature(address_sanitizer) || __has_feature(hwaddress_sanitizer) -/* Emulate GCC's __SANITIZE_ADDRESS__ flag */ +/* + * Treat __SANITIZE_HWADDRESS__ the same as __SANITIZE_ADDRESS__ in the kernel. + */ +#ifdef __SANITIZE_HWADDRESS__ #define __SANITIZE_ADDRESS__ +#endif + +#ifdef __SANITIZE_ADDRESS__ #define __no_sanitize_address \ __attribute__((no_sanitize("address", "hwaddress"))) #else #define __no_sanitize_address #endif -#if __has_feature(thread_sanitizer) -/* emulate gcc's __SANITIZE_THREAD__ flag */ -#define __SANITIZE_THREAD__ +#ifdef __SANITIZE_THREAD__ #define __no_sanitize_thread \ __attribute__((no_sanitize("thread"))) #else -- cgit v1.2.3