From: Uriel Guajardo <[email protected]>
KUnit tests will now fail if lockdep detects an error during a test
case.
The idea comes from how lib/locking-selftest [1] checks for lock errors: we
first if lock debugging is turned on. If not, an error must have
occurred, so we fail the test and restart lockdep for the next test case.
Like the locking selftests, we also fix possible preemption count
corruption from lock bugs.
Depends on kunit: support failure from dynamic analysis tools [2]
[1] https://elixir.bootlin.com/linux/v5.7.12/source/lib/locking-selftest.c#L1137
[2] https://lore.kernel.org/linux-kselftest/[email protected]/
Signed-off-by: Uriel Guajardo <[email protected]>
---
lib/kunit/test.c | 26 +++++++++++++++++++++++++-
1 file changed, 25 insertions(+), 1 deletion(-)
diff --git a/lib/kunit/test.c b/lib/kunit/test.c
index d8189d827368..0838ececa005 100644
--- a/lib/kunit/test.c
+++ b/lib/kunit/test.c
@@ -11,6 +11,8 @@
#include <linux/kref.h>
#include <linux/sched/debug.h>
#include <linux/sched.h>
+#include <linux/lockdep.h>
+#include <linux/debug_locks.h>
#include "debugfs.h"
#include "string-stream.h"
@@ -22,6 +24,26 @@ void kunit_fail_current_test(void)
kunit_set_failure(current->kunit_test);
}
+static inline void kunit_check_locking_bugs(struct kunit *test,
+ unsigned long saved_preempt_count)
+{
+ preempt_count_set(saved_preempt_count);
+#ifdef CONFIG_TRACE_IRQFLAGS
+ if (softirq_count())
+ current->softirqs_enabled = 0;
+ else
+ current->softirqs_enabled = 1;
+#endif
+#if IS_ENABLED(CONFIG_LOCKDEP)
+ local_irq_disable();
+ if (!debug_locks) {
+ kunit_set_failure(test);
+ lockdep_reset();
+ }
+ local_irq_enable();
+#endif
+}
+
static void kunit_print_tap_version(void)
{
static bool kunit_has_printed_tap_version;
@@ -289,6 +311,7 @@ static void kunit_try_run_case(void *data)
struct kunit *test = ctx->test;
struct kunit_suite *suite = ctx->suite;
struct kunit_case *test_case = ctx->test_case;
+ unsigned long saved_preempt_count = preempt_count();
current->kunit_test = test;
@@ -298,7 +321,8 @@ static void kunit_try_run_case(void *data)
* thread will resume control and handle any necessary clean up.
*/
kunit_run_case_internal(test, suite, test_case);
- /* This line may never be reached. */
+ /* These lines may never be reached. */
+ kunit_check_locking_bugs(test, saved_preempt_count);
kunit_run_case_cleanup(test, suite);
}
--
2.28.0.236.gb10cc79966-goog
On Thu, Aug 6, 2020 at 3:37 PM Uriel Guajardo <[email protected]> wrote:
>
> From: Uriel Guajardo <[email protected]>
>
> KUnit tests will now fail if lockdep detects an error during a test
> case.
>
> The idea comes from how lib/locking-selftest [1] checks for lock errors: we
> first if lock debugging is turned on. If not, an error must have
> occurred, so we fail the test and restart lockdep for the next test case.
>
> Like the locking selftests, we also fix possible preemption count
> corruption from lock bugs.
>
> Depends on kunit: support failure from dynamic analysis tools [2]
>
> [1] https://elixir.bootlin.com/linux/v5.7.12/source/lib/locking-selftest.c#L1137
>
> [2] https://lore.kernel.org/linux-kselftest/[email protected]/
>
> Signed-off-by: Uriel Guajardo <[email protected]>
> ---
> lib/kunit/test.c | 26 +++++++++++++++++++++++++-
> 1 file changed, 25 insertions(+), 1 deletion(-)
>
> diff --git a/lib/kunit/test.c b/lib/kunit/test.c
> index d8189d827368..0838ececa005 100644
> --- a/lib/kunit/test.c
> +++ b/lib/kunit/test.c
> @@ -11,6 +11,8 @@
> #include <linux/kref.h>
> #include <linux/sched/debug.h>
> #include <linux/sched.h>
> +#include <linux/lockdep.h>
> +#include <linux/debug_locks.h>
>
> #include "debugfs.h"
> #include "string-stream.h"
> @@ -22,6 +24,26 @@ void kunit_fail_current_test(void)
> kunit_set_failure(current->kunit_test);
> }
>
> +static inline void kunit_check_locking_bugs(struct kunit *test,
> + unsigned long saved_preempt_count)
> +{
> + preempt_count_set(saved_preempt_count);
> +#ifdef CONFIG_TRACE_IRQFLAGS
> + if (softirq_count())
> + current->softirqs_enabled = 0;
> + else
> + current->softirqs_enabled = 1;
> +#endif
I am not entirely sure why lib/locking-selftests enables/disables
softirqs, but I suspect it has to do with the fact that preempt_count
became corrupted, and somehow softirqs became incorrectly
enabled/disabled as a result. The resetting of the preemption count
will undo the enabling/disabling accordingly. Any insight on this
would be appreciated!
> +#if IS_ENABLED(CONFIG_LOCKDEP)
> + local_irq_disable();
> + if (!debug_locks) {
> + kunit_set_failure(test);
> + lockdep_reset();
> + }
> + local_irq_enable();
> +#endif
> +}
> +
> static void kunit_print_tap_version(void)
> {
> static bool kunit_has_printed_tap_version;
> @@ -289,6 +311,7 @@ static void kunit_try_run_case(void *data)
> struct kunit *test = ctx->test;
> struct kunit_suite *suite = ctx->suite;
> struct kunit_case *test_case = ctx->test_case;
> + unsigned long saved_preempt_count = preempt_count();
>
> current->kunit_test = test;
>
> @@ -298,7 +321,8 @@ static void kunit_try_run_case(void *data)
> * thread will resume control and handle any necessary clean up.
> */
> kunit_run_case_internal(test, suite, test_case);
> - /* This line may never be reached. */
> + /* These lines may never be reached. */
> + kunit_check_locking_bugs(test, saved_preempt_count);
> kunit_run_case_cleanup(test, suite);
> }
>
> --
> 2.28.0.236.gb10cc79966-goog
>
On Thu, Aug 6, 2020 at 1:37 PM Uriel Guajardo <[email protected]> wrote:
>
> From: Uriel Guajardo <[email protected]>
>
> KUnit tests will now fail if lockdep detects an error during a test
> case.
>
> The idea comes from how lib/locking-selftest [1] checks for lock errors: we
> first if lock debugging is turned on. If not, an error must have
> occurred, so we fail the test and restart lockdep for the next test case.
>
> Like the locking selftests, we also fix possible preemption count
> corruption from lock bugs.
>
> Depends on kunit: support failure from dynamic analysis tools [2]
>
> [1] https://elixir.bootlin.com/linux/v5.7.12/source/lib/locking-selftest.c#L1137
>
> [2] https://lore.kernel.org/linux-kselftest/[email protected]/
>
> Signed-off-by: Uriel Guajardo <[email protected]>
Reviewed-by: Brendan Higgins <[email protected]>
On Thu, Aug 6, 2020 at 1:43 PM Uriel Guajardo <[email protected]> wrote:
>
> On Thu, Aug 6, 2020 at 3:37 PM Uriel Guajardo <[email protected]> wrote:
> >
> > From: Uriel Guajardo <[email protected]>
> >
> > KUnit tests will now fail if lockdep detects an error during a test
> > case.
> >
> > The idea comes from how lib/locking-selftest [1] checks for lock errors: we
> > first if lock debugging is turned on. If not, an error must have
> > occurred, so we fail the test and restart lockdep for the next test case.
> >
> > Like the locking selftests, we also fix possible preemption count
> > corruption from lock bugs.
Sorry, just noticed: You probably want to send this to some of the
lockdep maintainers or the maintainers of the kselftest for lockdep.
> > Depends on kunit: support failure from dynamic analysis tools [2]
> >
> > [1] https://elixir.bootlin.com/linux/v5.7.12/source/lib/locking-selftest.c#L1137
> >
> > [2] https://lore.kernel.org/linux-kselftest/[email protected]/
> >
> > Signed-off-by: Uriel Guajardo <[email protected]>
> > ---
> > lib/kunit/test.c | 26 +++++++++++++++++++++++++-
> > 1 file changed, 25 insertions(+), 1 deletion(-)
> >
> > diff --git a/lib/kunit/test.c b/lib/kunit/test.c
> > index d8189d827368..0838ececa005 100644
> > --- a/lib/kunit/test.c
> > +++ b/lib/kunit/test.c
> > @@ -11,6 +11,8 @@
> > #include <linux/kref.h>
> > #include <linux/sched/debug.h>
> > #include <linux/sched.h>
> > +#include <linux/lockdep.h>
> > +#include <linux/debug_locks.h>
> >
> > #include "debugfs.h"
> > #include "string-stream.h"
> > @@ -22,6 +24,26 @@ void kunit_fail_current_test(void)
> > kunit_set_failure(current->kunit_test);
> > }
> >
> > +static inline void kunit_check_locking_bugs(struct kunit *test,
> > + unsigned long saved_preempt_count)
> > +{
> > + preempt_count_set(saved_preempt_count);
> > +#ifdef CONFIG_TRACE_IRQFLAGS
> > + if (softirq_count())
> > + current->softirqs_enabled = 0;
> > + else
> > + current->softirqs_enabled = 1;
> > +#endif
>
> I am not entirely sure why lib/locking-selftests enables/disables
> softirqs, but I suspect it has to do with the fact that preempt_count
> became corrupted, and somehow softirqs became incorrectly
> enabled/disabled as a result. The resetting of the preemption count
> will undo the enabling/disabling accordingly. Any insight on this
> would be appreciated!
>
> > +#if IS_ENABLED(CONFIG_LOCKDEP)
> > + local_irq_disable();
> > + if (!debug_locks) {
> > + kunit_set_failure(test);
> > + lockdep_reset();
> > + }
> > + local_irq_enable();
> > +#endif
> > +}
> > +
> > static void kunit_print_tap_version(void)
> > {
> > static bool kunit_has_printed_tap_version;
> > @@ -289,6 +311,7 @@ static void kunit_try_run_case(void *data)
> > struct kunit *test = ctx->test;
> > struct kunit_suite *suite = ctx->suite;
> > struct kunit_case *test_case = ctx->test_case;
> > + unsigned long saved_preempt_count = preempt_count();
> >
> > current->kunit_test = test;
> >
> > @@ -298,7 +321,8 @@ static void kunit_try_run_case(void *data)
> > * thread will resume control and handle any necessary clean up.
> > */
> > kunit_run_case_internal(test, suite, test_case);
> > - /* This line may never be reached. */
> > + /* These lines may never be reached. */
> > + kunit_check_locking_bugs(test, saved_preempt_count);
> > kunit_run_case_cleanup(test, suite);
> > }
> >
> > --
> > 2.28.0.236.gb10cc79966-goog
> >
On Mon, Aug 10, 2020 at 3:35 PM Brendan Higgins
<[email protected]> wrote:
>
> On Thu, Aug 6, 2020 at 1:43 PM Uriel Guajardo <[email protected]> wrote:
> >
> > On Thu, Aug 6, 2020 at 3:37 PM Uriel Guajardo <[email protected]> wrote:
> > >
> > > From: Uriel Guajardo <[email protected]>
> > >
> > > KUnit tests will now fail if lockdep detects an error during a test
> > > case.
> > >
> > > The idea comes from how lib/locking-selftest [1] checks for lock errors: we
> > > first if lock debugging is turned on. If not, an error must have
> > > occurred, so we fail the test and restart lockdep for the next test case.
> > >
> > > Like the locking selftests, we also fix possible preemption count
> > > corruption from lock bugs.
>
> Sorry, just noticed: You probably want to send this to some of the
> lockdep maintainers or the maintainers of the kselftest for lockdep.
>
Thanks for the reminder. CC'ed lockdep maintainers.
> > > Depends on kunit: support failure from dynamic analysis tools [2]
> > >
> > > [1] https://elixir.bootlin.com/linux/v5.7.12/source/lib/locking-selftest.c#L1137
> > >
> > > [2] https://lore.kernel.org/linux-kselftest/[email protected]/
> > >
> > > Signed-off-by: Uriel Guajardo <[email protected]>
> > > ---
> > > lib/kunit/test.c | 26 +++++++++++++++++++++++++-
> > > 1 file changed, 25 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/lib/kunit/test.c b/lib/kunit/test.c
> > > index d8189d827368..0838ececa005 100644
> > > --- a/lib/kunit/test.c
> > > +++ b/lib/kunit/test.c
> > > @@ -11,6 +11,8 @@
> > > #include <linux/kref.h>
> > > #include <linux/sched/debug.h>
> > > #include <linux/sched.h>
> > > +#include <linux/lockdep.h>
> > > +#include <linux/debug_locks.h>
> > >
> > > #include "debugfs.h"
> > > #include "string-stream.h"
> > > @@ -22,6 +24,26 @@ void kunit_fail_current_test(void)
> > > kunit_set_failure(current->kunit_test);
> > > }
> > >
> > > +static inline void kunit_check_locking_bugs(struct kunit *test,
> > > + unsigned long saved_preempt_count)
> > > +{
> > > + preempt_count_set(saved_preempt_count);
> > > +#ifdef CONFIG_TRACE_IRQFLAGS
> > > + if (softirq_count())
> > > + current->softirqs_enabled = 0;
> > > + else
> > > + current->softirqs_enabled = 1;
> > > +#endif
> >
> > I am not entirely sure why lib/locking-selftests enables/disables
> > softirqs, but I suspect it has to do with the fact that preempt_count
> > became corrupted, and somehow softirqs became incorrectly
> > enabled/disabled as a result. The resetting of the preemption count
> > will undo the enabling/disabling accordingly. Any insight on this
> > would be appreciated!
> >
> > > +#if IS_ENABLED(CONFIG_LOCKDEP)
> > > + local_irq_disable();
> > > + if (!debug_locks) {
> > > + kunit_set_failure(test);
> > > + lockdep_reset();
> > > + }
> > > + local_irq_enable();
> > > +#endif
> > > +}
> > > +
> > > static void kunit_print_tap_version(void)
> > > {
> > > static bool kunit_has_printed_tap_version;
> > > @@ -289,6 +311,7 @@ static void kunit_try_run_case(void *data)
> > > struct kunit *test = ctx->test;
> > > struct kunit_suite *suite = ctx->suite;
> > > struct kunit_case *test_case = ctx->test_case;
> > > + unsigned long saved_preempt_count = preempt_count();
> > >
> > > current->kunit_test = test;
> > >
> > > @@ -298,7 +321,8 @@ static void kunit_try_run_case(void *data)
> > > * thread will resume control and handle any necessary clean up.
> > > */
> > > kunit_run_case_internal(test, suite, test_case);
> > > - /* This line may never be reached. */
> > > + /* These lines may never be reached. */
> > > + kunit_check_locking_bugs(test, saved_preempt_count);
> > > kunit_run_case_cleanup(test, suite);
> > > }
> > >
> > > --
> > > 2.28.0.236.gb10cc79966-goog
> > >
On Mon, Aug 10, 2020 at 04:17:42PM -0500, Uriel Guajardo wrote:
> On Mon, Aug 10, 2020 at 3:35 PM Brendan Higgins
> <[email protected]> wrote:
> >
> > On Thu, Aug 6, 2020 at 1:43 PM Uriel Guajardo <[email protected]> wrote:
> > >
> > > On Thu, Aug 6, 2020 at 3:37 PM Uriel Guajardo <[email protected]> wrote:
> > > >
> > > > From: Uriel Guajardo <[email protected]>
> > > >
> > > > KUnit tests will now fail if lockdep detects an error during a test
> > > > case.
> > > >
> > > > The idea comes from how lib/locking-selftest [1] checks for lock errors: we
> > > > first if lock debugging is turned on. If not, an error must have
> > > > occurred, so we fail the test and restart lockdep for the next test case.
> > > >
> > > > Like the locking selftests, we also fix possible preemption count
> > > > corruption from lock bugs.
> >
> > Sorry, just noticed: You probably want to send this to some of the
> > lockdep maintainers or the maintainers of the kselftest for lockdep.
> >
>
> Thanks for the reminder. CC'ed lockdep maintainers.
Please resend as a whole, this is an unreadable mess.