+ idr-assert-static-storage-for-define_ida.patch added to mm-new branch

+ idr-assert-static-storage-for-define_ida.patch added to mm-new branch

[Andrew Morton]

The patch titled
     Subject: idr: assert static storage for DEFINE_IDA()
has been added to the -mm mm-new branch.  Its filename is
     idr-assert-static-storage-for-define_ida.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/idr-assert-static-storage-for-define_ida.patch

This patch will later appear in the mm-new branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Note, mm-new is a provisional staging ground for work-in-progress
patches, and acceptance into mm-new is a notification for others take
notice and to finish up reviews.  Please do not hesitate to respond to
review feedback and post updated versions to replace or incrementally
fixup patches in mm-new.

The mm-new branch of mm.git is not included in linux-next

If a few days of testing in mm-new is successful, the patch will me moved
into mm.git's mm-unstable branch, which is included in linux-next

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------------------------------------------------------
From: Yury Norov <ynorov@nvidia.com>
Subject: idr: assert static storage for DEFINE_IDA()
Date: Fri, 11 Sep 2026 18:14:42 -0400

DEFINE_IDA() uses IDA_INIT(), which initializes the embedded XArray lock
with a static spinlock initializer.  For an automatic local IDA, lockdep
cannot use the lock address as a persistent class key and reports "INFO:
trying to register non-static key" before disabling itself.

Apply ASSERT_STATIC_STORAGE() to DEFINE_IDA() so that this misuse is
rejected at compile time.  For example:

  void example(void)
  {
          DEFINE_IDA(ida);
          ida_destroy(&ida);
  }

GCC reports:

  error: initializer element is not constant
    name##_storage_check = &(name)
                           ^
  note: in expansion of macro 'ASSERT_STATIC_STORAGE'
    ASSERT_STATIC_STORAGE(name)
  note: in expansion of macro 'DEFINE_IDA'
    DEFINE_IDA(ida);

File-scope definitions and static DEFINE_IDA() within a function remain
valid.  Automatic local IDAs must instead be initialized with ida_init(). 
Direct uses of IDA_INIT() are not covered by this declaration check.

Convert the five automatic local IDAs in the userspace radix-tree tests to
ida_init() so they satisfy the new requirement.

Validated file-scope and static local definitions with a kernel object
build, and confirmed that an automatic local definition fails to compile.

Link: https://lore.kernel.org/20260911221444.1523311-3-ynorov@nvidia.com
Signed-off-by: Yury Norov <ynorov@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Alice Ryhl <aliceryhl@google.com>
Cc: Andrew Ballance <andrewjballance@gmail.com>
Cc: Christopher Li <sparse@chrisli.org>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
---

 include/linux/idr.h                 |    5 ++++-
 tools/testing/radix-tree/idr-test.c |   20 +++++++++++++++-----
 2 files changed, 19 insertions(+), 6 deletions(-)

--- a/include/linux/idr.h~idr-assert-static-storage-for-define_ida
+++ a/include/linux/idr.h
@@ -16,6 +16,7 @@
 #include <linux/gfp.h>
 #include <linux/percpu.h>
 #include <linux/cleanup.h>
+#include <linux/compiler.h>
 
 struct idr {
 	struct radix_tree_root	idr_rt;
@@ -269,7 +270,9 @@ struct ida {
 #define IDA_INIT(name)	{						\
 	.xa = XARRAY_INIT(name, IDA_INIT_FLAGS)				\
 }
-#define DEFINE_IDA(name)	struct ida name = IDA_INIT(name)
+#define DEFINE_IDA(name)							\
+	struct ida name = IDA_INIT(name);					\
+	ASSERT_STATIC_STORAGE(name)
 
 int ida_alloc_range(struct ida *, unsigned int min, unsigned int max, gfp_t);
 void ida_free(struct ida *, unsigned int id);
--- a/tools/testing/radix-tree/idr-test.c~idr-assert-static-storage-for-define_ida
+++ a/tools/testing/radix-tree/idr-test.c
@@ -460,9 +460,11 @@ void ida_dump(struct ida *);
  */
 void ida_check_nomem(void)
 {
-	DEFINE_IDA(ida);
+	struct ida ida;
 	int id;
 
+	ida_init(&ida);
+
 	id = ida_alloc_min(&ida, 256, GFP_NOWAIT);
 	IDA_BUG_ON(&ida, id != -ENOMEM);
 	id = ida_alloc_min(&ida, 1UL << 30, GFP_NOWAIT);
@@ -475,9 +477,11 @@ void ida_check_nomem(void)
  */
 void ida_check_conv_user(void)
 {
-	DEFINE_IDA(ida);
+	struct ida ida;
 	unsigned long i;
 
+	ida_init(&ida);
+
 	for (i = 0; i < 1000000; i++) {
 		int id = ida_alloc(&ida, GFP_NOWAIT);
 		if (id == -ENOMEM) {
@@ -496,11 +500,13 @@ void ida_check_conv_user(void)
 
 void ida_check_random(void)
 {
-	DEFINE_IDA(ida);
+	struct ida ida;
 	DECLARE_BITMAP(bitmap, 2048);
 	unsigned int i;
 	time_t s = time(NULL);
 
+	ida_init(&ida);
+
  repeat:
 	memset(bitmap, 0, sizeof(bitmap));
 	for (i = 0; i < 100000; i++) {
@@ -522,9 +528,11 @@ void ida_check_random(void)
 
 void ida_alloc_free_test(void)
 {
-	DEFINE_IDA(ida);
+	struct ida ida;
 	unsigned long i;
 
+	ida_init(&ida);
+
 	for (i = 0; i < 10000; i++)
 		assert(ida_alloc_max(&ida, 20000, GFP_KERNEL) == i);
 	assert(ida_alloc_range(&ida, 5, 30, GFP_KERNEL) < 0);
@@ -576,10 +584,12 @@ static void *ida_leak_fn(void *arg)
 
 void ida_thread_tests(void)
 {
-	DEFINE_IDA(ida);
+	struct ida ida;
 	pthread_t threads[20];
 	int i;
 
+	ida_init(&ida);
+
 	for (i = 0; i < ARRAY_SIZE(threads); i++)
 		if (pthread_create(&threads[i], NULL, ida_random_fn, NULL)) {
 			perror("creating ida thread");
_

Patches currently in -mm which might be from ynorov@nvidia.com are

lib-fix-lock-initialization-in-region-allocation-benchmark.patch
compilerh-add-assert_static_storage.patch
idr-assert-static-storage-for-define_ida.patch
maple_tree-assert-static-storage-for-define_mtree.patch