From: Vlastimil Babka <vbabka@xxxxxxx> 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@xxxxxxxxx Signed-off-by: Vlastimil Babka <vbabka@xxxxxxx> Signed-off-by: Oliver Glitta <glittao@xxxxxxxxx> Reviewed-by: Brendan Higgins <brendanhiggins@xxxxxxxxxx> Cc: Christoph Lameter <cl@xxxxxxxxx> Cc: Daniel Latypov <dlatypov@xxxxxxxxxx> Cc: David Rientjes <rientjes@xxxxxxxxxx> Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx> Cc: Marco Elver <elver@xxxxxxxxxx> Cc: Pekka Enberg <penberg@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- 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; _
