On Kunit, if we allocate a resource A and B on this order, with its deferred actions to free them. The resource stack would be something like this: +---------+ | free(B) | +---------+ | ... | +---------+ | free(A) | +---------+ If the deferred action of A accesses B, this would cause a use-after-free bug. To solve that, we need a way to change the order of actions. Create a function to move an action to the top of the resource stack, as shown in the diagram below. +---------+ +---------+ | free(B) | | free(A) | +---------+ +---------+ | ... | -> | free(B) | +---------+ +---------+ | free(A) | | ... | +---------+ +---------+ Signed-off-by: Arthur Grillo <arthurgrillo@xxxxxxxxxx> --- include/kunit/resource.h | 17 +++++++++++++++++ lib/kunit/resource.c | 19 +++++++++++++++++++ 2 files changed, 36 insertions(+) diff --git a/include/kunit/resource.h b/include/kunit/resource.h index c7383e90f5c9..c598b23680e3 100644 --- a/include/kunit/resource.h +++ b/include/kunit/resource.h @@ -479,4 +479,21 @@ void kunit_remove_action(struct kunit *test, void kunit_release_action(struct kunit *test, kunit_action_t *action, void *ctx); + +/** + * kunit_move_action_to_top_or_reset - Move a previously added action to the top + * of the order of actions calls. + * @test: Test case to associate the action with. + * @action: The function to run on test exit + * @ctx: Data passed into @func + * + * Reorder the action stack, by moving the desired action to the top. + * + * Returns: + * 0 on success, an error if the action could not be inserted on the top. + */ +int kunit_move_action_to_top_or_reset(struct kunit *test, + kunit_action_t *action, + void *ctx); + #endif /* _KUNIT_RESOURCE_H */ diff --git a/lib/kunit/resource.c b/lib/kunit/resource.c index f0209252b179..fe40a34b62a6 100644 --- a/lib/kunit/resource.c +++ b/lib/kunit/resource.c @@ -176,3 +176,22 @@ void kunit_release_action(struct kunit *test, } } EXPORT_SYMBOL_GPL(kunit_release_action); + +int kunit_move_action_to_top_or_reset(struct kunit *test, + kunit_action_t *action, + void *ctx) +{ + struct kunit_action_ctx match_ctx; + struct kunit_resource *res; + + match_ctx.func = action; + match_ctx.ctx = ctx; + res = kunit_find_resource(test, __kunit_action_match, &match_ctx); + if (res) { + kunit_remove_action(test, action, ctx); + return kunit_add_action_or_reset(test, action, ctx); + } + + return 0; +} +EXPORT_SYMBOL_GPL(kunit_move_action_to_top_or_reset); -- 2.41.0