+ kunit-make-test-lock-irq-safe.patch added to -mm tree

+ kunit-make-test-lock-irq-safe.patch added to -mm tree

[akpm]

The patch titled
     Subject: kunit: make test->lock irq safe
has been added to the -mm tree.  Its filename is
     kunit-make-test-lock-irq-safe.patch

This patch should soon appear at
    https://ozlabs.org/~akpm/mmots/broken-out/kunit-make-test-lock-irq-safe.patch
and later at
    https://ozlabs.org/~akpm/mmotm/broken-out/kunit-make-test-lock-irq-safe.patch

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------------------------------------------------------
From: Vlastimil Babka <vbabka@suse.cz>
Subject: kunit: make test->lock irq safe

The upcoming SLUB kunit test will be calling kunit_find_named_resource()
from a context with disabled interrupts.  That means kunit's test->lock
needs to be IRQ safe to avoid potential deadlocks and lockdep splats.

This patch therefore changes the test->lock usage to spin_lock_irqsave()
and spin_unlock_irqrestore().

Link: https://lkml.kernel.org/r/20210511150734.3492-1-glittao@gmail.com
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Oliver Glitta <glittao@gmail.com>
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Daniel Latypov <dlatypov@google.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Marco Elver <elver@google.com>
Cc: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 include/kunit/test.h |    5 +++--
 lib/kunit/test.c     |   18 +++++++++++-------
 2 files changed, 14 insertions(+), 9 deletions(-)

--- a/include/kunit/test.h~kunit-make-test-lock-irq-safe
+++ a/include/kunit/test.h
@@ -515,8 +515,9 @@ kunit_find_resource(struct kunit *test,
 		    void *match_data)
 {
 	struct kunit_resource *res, *found = NULL;
+	unsigned long flags;
 
-	spin_lock(&test->lock);
+	spin_lock_irqsave(&test->lock, flags);
 
 	list_for_each_entry_reverse(res, &test->resources, node) {
 		if (match(test, res, (void *)match_data)) {
@@ -526,7 +527,7 @@ kunit_find_resource(struct kunit *test,
 		}
 	}
 
-	spin_unlock(&test->lock);
+	spin_unlock_irqrestore(&test->lock, flags);
 
 	return found;
 }
--- a/lib/kunit/test.c~kunit-make-test-lock-irq-safe
+++ a/lib/kunit/test.c
@@ -475,6 +475,7 @@ int kunit_add_resource(struct kunit *tes
 		       void *data)
 {
 	int ret = 0;
+	unsigned long flags;
 
 	res->free = free;
 	kref_init(&res->refcount);
@@ -487,10 +488,10 @@ int kunit_add_resource(struct kunit *tes
 		res->data = data;
 	}
 
-	spin_lock(&test->lock);
+	spin_lock_irqsave(&test->lock, flags);
 	list_add_tail(&res->node, &test->resources);
 	/* refcount for list is established by kref_init() */
-	spin_unlock(&test->lock);
+	spin_unlock_irqrestore(&test->lock, flags);
 
 	return ret;
 }
@@ -548,9 +549,11 @@ EXPORT_SYMBOL_GPL(kunit_alloc_and_get_re
 
 void kunit_remove_resource(struct kunit *test, struct kunit_resource *res)
 {
-	spin_lock(&test->lock);
+	unsigned long flags;
+
+	spin_lock_irqsave(&test->lock, flags);
 	list_del(&res->node);
-	spin_unlock(&test->lock);
+	spin_unlock_irqrestore(&test->lock, flags);
 	kunit_put_resource(res);
 }
 EXPORT_SYMBOL_GPL(kunit_remove_resource);
@@ -630,6 +633,7 @@ EXPORT_SYMBOL_GPL(kunit_kfree);
 void kunit_cleanup(struct kunit *test)
 {
 	struct kunit_resource *res;
+	unsigned long flags;
 
 	/*
 	 * test->resources is a stack - each allocation must be freed in the
@@ -641,9 +645,9 @@ void kunit_cleanup(struct kunit *test)
 	 * protect against the current node being deleted, not the next.
 	 */
 	while (true) {
-		spin_lock(&test->lock);
+		spin_lock_irqsave(&test->lock, flags);
 		if (list_empty(&test->resources)) {
-			spin_unlock(&test->lock);
+			spin_unlock_irqrestore(&test->lock, flags);
 			break;
 		}
 		res = list_last_entry(&test->resources,
@@ -654,7 +658,7 @@ void kunit_cleanup(struct kunit *test)
 		 * resource, and this can't happen if the test->lock
 		 * is held.
 		 */
-		spin_unlock(&test->lock);
+		spin_unlock_irqrestore(&test->lock, flags);
 		kunit_remove_resource(test, res);
 	}
 	current->kunit_test = NULL;
_

Patches currently in -mm which might be from vbabka@suse.cz are

mm-slub-move-slub_debug-static-key-enabling-outside-slab_mutex.patch
kunit-make-test-lock-irq-safe.patch
mm-memcg-slab-create-a-new-set-of-kmalloc-cg-n-caches-fix.patch