kmalloc_obj fixes for v7.0-rc2

- Fix pointer-to-array allocation types for ubd and kcsan
 
 - Force size overflow helpers to __always_inline
 
 - Bump __builtin_counted_by_ref to Clang 22.1 from 22.0 (Nathan Chancellor)
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Merge tag 'kmalloc_obj-v7.0-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull kmalloc_obj fixes from Kees Cook:

 - Fix pointer-to-array allocation types for ubd and kcsan

 - Force size overflow helpers to __always_inline

 - Bump __builtin_counted_by_ref to Clang 22.1 from 22.0 (Nathan Chancellor)

* tag 'kmalloc_obj-v7.0-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  kcsan: test: Adjust "expect" allocation type for kmalloc_obj
  overflow: Make sure size helpers are always inlined
  init/Kconfig: Adjust fixed clang version for __builtin_counted_by_ref
  ubd: Use pointer-to-pointers for io_thread_req arrays

arch/um/drivers/ubd_kern.c

@@ -69,11 +69,11 @@ struct io_thread_req {
 };
 
 
-static struct io_thread_req * (*irq_req_buffer)[];
+static struct io_thread_req **irq_req_buffer;
 static struct io_thread_req *irq_remainder;
 static int irq_remainder_size;
 
-static struct io_thread_req * (*io_req_buffer)[];
+static struct io_thread_req **io_req_buffer;
 static struct io_thread_req *io_remainder;
 static int io_remainder_size;
 
@@ -398,7 +398,7 @@ static int thread_fd = -1;
 
 static int bulk_req_safe_read(
 	int fd,
-	struct io_thread_req * (*request_buffer)[],
+	struct io_thread_req **request_buffer,
 	struct io_thread_req **remainder,
 	int *remainder_size,
 	int max_recs
@@ -465,7 +465,7 @@ static irqreturn_t ubd_intr(int irq, void *dev)
 			&irq_remainder, &irq_remainder_size,
 			UBD_REQ_BUFFER_SIZE)) >= 0) {
 		for (i = 0; i < len / sizeof(struct io_thread_req *); i++)
-			ubd_end_request((*irq_req_buffer)[i]);
+			ubd_end_request(irq_req_buffer[i]);
 	}
 
 	if (len < 0 && len != -EAGAIN)
@@ -1512,7 +1512,7 @@ void *io_thread(void *arg)
 		}
 
 		for (count = 0; count < n/sizeof(struct io_thread_req *); count++) {
-			struct io_thread_req *req = (*io_req_buffer)[count];
+			struct io_thread_req *req = io_req_buffer[count];
 			int i;
 
 			io_count++;

include/linux/overflow.h

@@ -42,7 +42,7 @@
  * both the type-agnostic benefits of the macros while also being able to
  * enforce that the return value is, in fact, checked.
  */
-static inline bool __must_check __must_check_overflow(bool overflow)
+static __always_inline bool __must_check __must_check_overflow(bool overflow)
 {
 	return unlikely(overflow);
 }
@@ -327,7 +327,7 @@ static inline bool __must_check __must_check_overflow(bool overflow)
  * with any overflow causing the return value to be SIZE_MAX. The
  * lvalue must be size_t to avoid implicit type conversion.
  */
-static inline size_t __must_check size_mul(size_t factor1, size_t factor2)
+static __always_inline size_t __must_check size_mul(size_t factor1, size_t factor2)
 {
 	size_t bytes;
 
@@ -346,7 +346,7 @@ static inline size_t __must_check size_mul(size_t factor1, size_t factor2)
  * with any overflow causing the return value to be SIZE_MAX. The
  * lvalue must be size_t to avoid implicit type conversion.
  */
-static inline size_t __must_check size_add(size_t addend1, size_t addend2)
+static __always_inline size_t __must_check size_add(size_t addend1, size_t addend2)
 {
 	size_t bytes;
 
@@ -367,7 +367,7 @@ static inline size_t __must_check size_add(size_t addend1, size_t addend2)
  * argument may be SIZE_MAX (or the result with be forced to SIZE_MAX).
  * The lvalue must be size_t to avoid implicit type conversion.
  */
-static inline size_t __must_check size_sub(size_t minuend, size_t subtrahend)
+static __always_inline size_t __must_check size_sub(size_t minuend, size_t subtrahend)
 {
 	size_t bytes;
 

init/Kconfig

@@ -153,7 +153,7 @@ config CC_HAS_COUNTED_BY_PTR
 config CC_HAS_BROKEN_COUNTED_BY_REF
 	bool
 	# https://github.com/llvm/llvm-project/issues/182575
-	default y if CC_IS_CLANG && CLANG_VERSION < 220000
+	default y if CC_IS_CLANG && CLANG_VERSION < 220100
 
 config CC_HAS_MULTIDIMENSIONAL_NONSTRING
 	def_bool $(success,echo 'char tag[][4] __attribute__((__nonstring__)) = { };' | $(CC) $(CLANG_FLAGS) -x c - -c -o /dev/null -Werror)

kernel/kcsan/kcsan_test.c

@@ -168,7 +168,7 @@ static bool __report_matches(const struct expect_report *r)
 	if (!report_available())
 		return false;
 
-	expect = kmalloc_obj(observed.lines);
+	expect = (typeof(expect))kmalloc_obj(observed.lines);
 	if (WARN_ON(!expect))
 		return false;