On Fri, 22 Sept 2023 at 15:11, 'Jinjie Ruan' via KUnit Development
<kunit-dev@xxxxxxxxxxxxxxxx> wrote:
>
> When CONFIG_KUNIT_ALL_TESTS=y, making CONFIG_DEBUG_KMEMLEAK=y and
> CONFIG_DEBUG_KMEMLEAK_AUTO_SCAN=y, the below memory leak is detected.
>
> If kunit_filter_suites() succeeds, not only copy but also filtered_suite
> and filtered_suite->test_cases should be freed.
>
> So as Rae suggested, to avoid the suite set never be freed when
> KUNIT_ASSERT_EQ() fails and exits after kunit_filter_suites() succeeds,
> update kfree_at_end() func to free_suite_set_at_end() to use
> kunit_free_suite_set() to free them as kunit_module_exit() and
> kunit_run_all_tests() do it. As the second arg got of
> free_suite_set_at_end() is a local variable, copy it for free to avoid
> wild-memory-access. After applying this patch, the following memory leak
> is never detected.
>
> unreferenced object 0xffff8881001de400 (size 1024):
> comm "kunit_try_catch", pid 1396, jiffies 4294720452 (age 932.801s)
> hex dump (first 32 bytes):
> 73 75 69 74 65 32 00 00 00 00 00 00 00 00 00 00 suite2..........
> 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
> backtrace:
> [<ffffffff817db753>] __kmalloc_node_track_caller+0x53/0x150
> [<ffffffff817bd242>] kmemdup+0x22/0x50
> [<ffffffff829e961d>] kunit_filter_suites+0x44d/0xcc0
> [<ffffffff829eb69f>] filter_suites_test+0x12f/0x360
> [<ffffffff829e802a>] kunit_generic_run_threadfn_adapter+0x4a/0x90
> [<ffffffff81236fc6>] kthread+0x2b6/0x380
> [<ffffffff81096afd>] ret_from_fork+0x2d/0x70
> [<ffffffff81003511>] ret_from_fork_asm+0x11/0x20
> unreferenced object 0xffff8881052cd388 (size 192):
> comm "kunit_try_catch", pid 1396, jiffies 4294720452 (age 932.801s)
> hex dump (first 32 bytes):
> a0 85 9e 82 ff ff ff ff 80 cd 7c 84 ff ff ff ff ..........|.....
> 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
> backtrace:
> [<ffffffff817dbad2>] __kmalloc+0x52/0x150
> [<ffffffff829e9651>] kunit_filter_suites+0x481/0xcc0
> [<ffffffff829eb69f>] filter_suites_test+0x12f/0x360
> [<ffffffff829e802a>] kunit_generic_run_threadfn_adapter+0x4a/0x90
> [<ffffffff81236fc6>] kthread+0x2b6/0x380
> [<ffffffff81096afd>] ret_from_fork+0x2d/0x70
> [<ffffffff81003511>] ret_from_fork_asm+0x11/0x20
>
> unreferenced object 0xffff888100da8400 (size 1024):
> comm "kunit_try_catch", pid 1398, jiffies 4294720454 (age 781.945s)
> hex dump (first 32 bytes):
> 73 75 69 74 65 32 00 00 00 00 00 00 00 00 00 00 suite2..........
> 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
> backtrace:
> [<ffffffff817db753>] __kmalloc_node_track_caller+0x53/0x150
> [<ffffffff817bd242>] kmemdup+0x22/0x50
> [<ffffffff829e961d>] kunit_filter_suites+0x44d/0xcc0
> [<ffffffff829eb13f>] filter_suites_test_glob_test+0x12f/0x560
> [<ffffffff829e802a>] kunit_generic_run_threadfn_adapter+0x4a/0x90
> [<ffffffff81236fc6>] kthread+0x2b6/0x380
> [<ffffffff81096afd>] ret_from_fork+0x2d/0x70
> [<ffffffff81003511>] ret_from_fork_asm+0x11/0x20
> unreferenced object 0xffff888105117878 (size 96):
> comm "kunit_try_catch", pid 1398, jiffies 4294720454 (age 781.945s)
> hex dump (first 32 bytes):
> a0 85 9e 82 ff ff ff ff a0 ac 7c 84 ff ff ff ff ..........|.....
> 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
> backtrace:
> [<ffffffff817dbad2>] __kmalloc+0x52/0x150
> [<ffffffff829e9651>] kunit_filter_suites+0x481/0xcc0
> [<ffffffff829eb13f>] filter_suites_test_glob_test+0x12f/0x560
> [<ffffffff829e802a>] kunit_generic_run_threadfn_adapter+0x4a/0x90
> [<ffffffff81236fc6>] kthread+0x2b6/0x380
> [<ffffffff81096afd>] ret_from_fork+0x2d/0x70
> [<ffffffff81003511>] ret_from_fork_asm+0x11/0x20
> unreferenced object 0xffff888102c31c00 (size 1024):
> comm "kunit_try_catch", pid 1404, jiffies 4294720460 (age 781.948s)
> hex dump (first 32 bytes):
> 6e 6f 72 6d 61 6c 5f 73 75 69 74 65 00 00 00 00 normal_suite....
> 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
> backtrace:
> [<ffffffff817db753>] __kmalloc_node_track_caller+0x53/0x150
> [<ffffffff817bd242>] kmemdup+0x22/0x50
> [<ffffffff829ecf17>] kunit_filter_attr_tests+0xf7/0x860
> [<ffffffff829e99ff>] kunit_filter_suites+0x82f/0xcc0
> [<ffffffff829ea975>] filter_attr_test+0x195/0x5f0
> [<ffffffff829e802a>] kunit_generic_run_threadfn_adapter+0x4a/0x90
> [<ffffffff81236fc6>] kthread+0x2b6/0x380
> [<ffffffff81096afd>] ret_from_fork+0x2d/0x70
> [<ffffffff81003511>] ret_from_fork_asm+0x11/0x20
> unreferenced object 0xffff8881052cd250 (size 192):
> comm "kunit_try_catch", pid 1404, jiffies 4294720460 (age 781.948s)
> hex dump (first 32 bytes):
> a0 85 9e 82 ff ff ff ff 00 a9 7c 84 ff ff ff ff ..........|.....
> 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
> backtrace:
> [<ffffffff817dbad2>] __kmalloc+0x52/0x150
> [<ffffffff829ecfc1>] kunit_filter_attr_tests+0x1a1/0x860
> [<ffffffff829e99ff>] kunit_filter_suites+0x82f/0xcc0
> [<ffffffff829ea975>] filter_attr_test+0x195/0x5f0
> [<ffffffff829e802a>] kunit_generic_run_threadfn_adapter+0x4a/0x90
> [<ffffffff81236fc6>] kthread+0x2b6/0x380
> [<ffffffff81096afd>] ret_from_fork+0x2d/0x70
> [<ffffffff81003511>] ret_from_fork_asm+0x11/0x20
> unreferenced object 0xffff888104f4e400 (size 1024):
> comm "kunit_try_catch", pid 1408, jiffies 4294720464 (age 781.944s)
> hex dump (first 32 bytes):
> 73 75 69 74 65 00 00 00 00 00 00 00 00 00 00 00 suite...........
> 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
> backtrace:
> [<ffffffff817db753>] __kmalloc_node_track_caller+0x53/0x150
> [<ffffffff817bd242>] kmemdup+0x22/0x50
> [<ffffffff829ecf17>] kunit_filter_attr_tests+0xf7/0x860
> [<ffffffff829e99ff>] kunit_filter_suites+0x82f/0xcc0
> [<ffffffff829e9fc3>] filter_attr_skip_test+0x133/0x6e0
> [<ffffffff829e802a>] kunit_generic_run_threadfn_adapter+0x4a/0x90
> [<ffffffff81236fc6>] kthread+0x2b6/0x380
> [<ffffffff81096afd>] ret_from_fork+0x2d/0x70
> [<ffffffff81003511>] ret_from_fork_asm+0x11/0x20
> unreferenced object 0xffff8881052cc620 (size 192):
> comm "kunit_try_catch", pid 1408, jiffies 4294720464 (age 781.944s)
> hex dump (first 32 bytes):
> a0 85 9e 82 ff ff ff ff c0 a8 7c 84 ff ff ff ff ..........|.....
> 00 00 00 00 00 00 00 00 02 00 00 00 02 00 00 00 ................
> backtrace:
> [<ffffffff817dbad2>] __kmalloc+0x52/0x150
> [<ffffffff829ecfc1>] kunit_filter_attr_tests+0x1a1/0x860
> [<ffffffff829e99ff>] kunit_filter_suites+0x82f/0xcc0
> [<ffffffff829e9fc3>] filter_attr_skip_test+0x133/0x6e0
> [<ffffffff829e802a>] kunit_generic_run_threadfn_adapter+0x4a/0x90
> [<ffffffff81236fc6>] kthread+0x2b6/0x380
> [<ffffffff81096afd>] ret_from_fork+0x2d/0x70
> [<ffffffff81003511>] ret_from_fork_asm+0x11/0x20
>
> Fixes: e5857d396f35 ("kunit: flatten kunit_suite*** to kunit_suite** in .kunit_test_suites")
> Signed-off-by: Jinjie Ruan <ruanjinjie@xxxxxxxxxx>
> Suggested-by: Rae Moar <rmoar@xxxxxxxxxx>
> Reported-by: kernel test robot <lkp@xxxxxxxxx>
> Closes: https://lore.kernel.org/oe-kbuild-all/202309142251.uJ8saAZv-lkp@xxxxxxxxx/
> ---
> v3:
> - Update the kfree_at_end() to use kunit_free_suite_set() instead calling it
> directly.
> - Update the commit message.
> - Add Suggested-by.
> v2:
> - Add the memory leak backtrace.
> - Remove the unused func kfree_at_end() kernel test robot noticed.
> - Update the commit message.
> ---
Ah, I like this much more than v2, thanks!
The need to make a new struct kunit_suite_set so it stays in scope is
a bit ugly, but is probably the best we can do.
My only suggestion is that we make free_suite_set() take a void *,
which would let us avoid to kunit_action_t function pointer cast,
which will break CFI, and result in some warnings with clang 16+ and
W=1.
See:
https://lore.kernel.org/all/20230915050125.3609689-1-davidgow@xxxxxxxxxx/
(The existing code was already broken, so I'm happy to accept this
as-is, and fix it separately if you prefer.)
Otherwise,
Reviewed-by: David Gow <davidgow@xxxxxxxxxx>
Cheers,
-- David
> lib/kunit/executor_test.c | 35 ++++++++++++++++++++++-------------
> 1 file changed, 22 insertions(+), 13 deletions(-)
>
> diff --git a/lib/kunit/executor_test.c b/lib/kunit/executor_test.c
> index b4f6f96b2844..6b68959def9d 100644
> --- a/lib/kunit/executor_test.c
> +++ b/lib/kunit/executor_test.c
> @@ -9,7 +9,7 @@
> #include <kunit/test.h>
> #include <kunit/attributes.h>
>
> -static void kfree_at_end(struct kunit *test, const void *to_free);
> +static void free_suite_set_at_end(struct kunit *test, const void *to_free);
> static struct kunit_suite *alloc_fake_suite(struct kunit *test,
> const char *suite_name,
> struct kunit_case *test_cases);
> @@ -56,7 +56,7 @@ static void filter_suites_test(struct kunit *test)
> got = kunit_filter_suites(&suite_set, "suite2", NULL, NULL, &err);
> KUNIT_ASSERT_NOT_ERR_OR_NULL(test, got.start);
> KUNIT_ASSERT_EQ(test, err, 0);
> - kfree_at_end(test, got.start);
> + free_suite_set_at_end(test, &got);
>
> /* Validate we just have suite2 */
> KUNIT_ASSERT_NOT_ERR_OR_NULL(test, got.start[0]);
> @@ -82,7 +82,7 @@ static void filter_suites_test_glob_test(struct kunit *test)
> got = kunit_filter_suites(&suite_set, "suite2.test2", NULL, NULL, &err);
> KUNIT_ASSERT_NOT_ERR_OR_NULL(test, got.start);
> KUNIT_ASSERT_EQ(test, err, 0);
> - kfree_at_end(test, got.start);
> + free_suite_set_at_end(test, &got);
>
> /* Validate we just have suite2 */
> KUNIT_ASSERT_NOT_ERR_OR_NULL(test, got.start[0]);
> @@ -109,7 +109,7 @@ static void filter_suites_to_empty_test(struct kunit *test)
>
> got = kunit_filter_suites(&suite_set, "not_found", NULL, NULL, &err);
> KUNIT_ASSERT_EQ(test, err, 0);
> - kfree_at_end(test, got.start); /* just in case */
> + free_suite_set_at_end(test, &got); /* just in case */
>
> KUNIT_EXPECT_PTR_EQ_MSG(test, got.start, got.end,
> "should be empty to indicate no match");
> @@ -172,7 +172,7 @@ static void filter_attr_test(struct kunit *test)
> got = kunit_filter_suites(&suite_set, NULL, filter, NULL, &err);
> KUNIT_ASSERT_NOT_ERR_OR_NULL(test, got.start);
> KUNIT_ASSERT_EQ(test, err, 0);
> - kfree_at_end(test, got.start);
> + free_suite_set_at_end(test, &got);
>
> /* Validate we just have normal_suite */
> KUNIT_ASSERT_NOT_ERR_OR_NULL(test, got.start[0]);
> @@ -200,7 +200,7 @@ static void filter_attr_empty_test(struct kunit *test)
>
> got = kunit_filter_suites(&suite_set, NULL, filter, NULL, &err);
> KUNIT_ASSERT_EQ(test, err, 0);
> - kfree_at_end(test, got.start); /* just in case */
> + free_suite_set_at_end(test, &got); /* just in case */
>
> KUNIT_EXPECT_PTR_EQ_MSG(test, got.start, got.end,
> "should be empty to indicate no match");
> @@ -222,7 +222,7 @@ static void filter_attr_skip_test(struct kunit *test)
> got = kunit_filter_suites(&suite_set, NULL, filter, "skip", &err);
> KUNIT_ASSERT_NOT_ERR_OR_NULL(test, got.start);
> KUNIT_ASSERT_EQ(test, err, 0);
> - kfree_at_end(test, got.start);
> + free_suite_set_at_end(test, &got);
>
> /* Validate we have both the slow and normal test */
> KUNIT_ASSERT_NOT_ERR_OR_NULL(test, got.start[0]->test_cases);
> @@ -256,18 +256,27 @@ kunit_test_suites(&executor_test_suite);
>
> /* Test helpers */
>
> -/* Use the resource API to register a call to kfree(to_free).
> +static void free_suite_set(struct kunit_suite_set *suite_set)
If this accepted suite_set as a void *...
> +{
> + kunit_free_suite_set(*suite_set);
(And casted it to struct kunit_suite_set * here).
> + kfree(suite_set);
> +}
> +
> +/* Use the resource API to register a call to free_suite_set.
> * Since we never actually use the resource, it's safe to use on const data.
> */
> -static void kfree_at_end(struct kunit *test, const void *to_free)
> +static void free_suite_set_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))
> + if (!((struct kunit_suite_set *)to_free)->start)
> return;
>
> + struct kunit_suite_set *free = kzalloc(sizeof(struct kunit_suite_set),
> + GFP_KERNEL);
> + *free = *(struct kunit_suite_set *)to_free;
> +
> kunit_add_action(test,
> - (kunit_action_t *)kfree,
> - (void *)to_free);
> + (kunit_action_t *)free_suite_set,
...we could get rid of this cast.
> + (void *)free);
> }
>
> static struct kunit_suite *alloc_fake_suite(struct kunit *test,
> --
> 2.34.1
>
> --
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