On Thu, Sep 9, 2021 at 9:59 AM Daniel Latypov dlatypov@google.com wrote:
On Thu, Sep 9, 2021 at 12:26 AM 'Xiyu Yang' via KUnit Development kunit-dev@googlegroups.com wrote:
The reference counting issue happens in the normal path of kfree_at_end(). When kunit_alloc_and_get_resource() is invoked, the function forgets to handle the returned resource object, whose refcount increased inside, causing a refcount leak.
Fix this issue by calling kunit_alloc_resource() instead of kunit_alloc_and_get_resource().
Signed-off-by: Xiyu Yang xiyuyang19@fudan.edu.cn Signed-off-by: Xin Tan tanxin.ctf@gmail.com
Reviewed-by: Daniel Latypov dlatypov@google.com
Ah, thanks for finding and fixing this! We really should have better documentation/otherwise make it clearer that people shouldn't use the "_and_get" version.
I went and added some pr_info() calls to verify that these were being leaked before and they're fixed now.
I copy-pasted this mistake into https://lore.kernel.org/linux-kselftest/20210831171926.3832806-2-dlatypov@go.... I'll send a v3 fix for that patch as well.
Fixed that patch: https://lore.kernel.org/linux-kselftest/20210909171052.3192326-2-dlatypov@go...
I assume this patch and that one shouldn't have merge conflicts, so we don't need these to be applied in any specific order.
lib/kunit/executor_test.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/lib/kunit/executor_test.c b/lib/kunit/executor_test.c index cdbe54b16501..c2dcfb1f6e97 100644 --- a/lib/kunit/executor_test.c +++ b/lib/kunit/executor_test.c @@ -116,7 +116,7 @@ static void kfree_at_end(struct kunit *test, const void *to_free) /* kfree() handles NULL already, but avoid allocating a no-op cleanup. */ if (IS_ERR_OR_NULL(to_free)) return;
kunit_alloc_and_get_resource(test, NULL, kfree_res_free, GFP_KERNEL,
kunit_alloc_resource(test, NULL, kfree_res_free, GFP_KERNEL, (void *)to_free);}
-- 2.7.4
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