[PATCH] sptests: add test for priority inversion with multiple locks
Joel Sherrill
Joel.Sherrill at OARcorp.com
Sat May 18 19:06:40 UTC 2013
When the other test works should we remove the original test submitted with this code?
I think we should switch to this as the default behavior when it works.
We do need to check coverage.
Gedare Bloom <gedare at rtems.org> wrote:
This test exposes a potential priority inversion when priority
inheritance is used and multiple locks are acquired by a low priority
task. The scenario consists of 2 tasks of different priority and 2
semaphore/mutexes using priority inheritance.
Using ENABLE_STRICT_ORDER_MUTEX=1 prevents the priority inversion.
I hope to write another test soon that demonstrates a different
priority inversion when there are 3 tasks and 2 mutexes while using
the current implementation of strict order mutex.
-Gedare
On Sat, May 18, 2013 at 2:57 PM, Gedare Bloom <gedare at rtems.org> wrote:
> ---
> testsuites/sptests/Makefile.am | 2 +-
> testsuites/sptests/configure.ac | 1 +
> testsuites/sptests/spsem01/Makefile.am | 21 +++++
> testsuites/sptests/spsem01/init.c | 154 ++++++++++++++++++++++++++++++++
> testsuites/sptests/spsem01/spsem01.doc | 19 ++++
> testsuites/sptests/spsem01/spsem01.scn | 16 ++++
> 6 files changed, 212 insertions(+), 1 deletions(-)
> create mode 100644 testsuites/sptests/spsem01/Makefile.am
> create mode 100644 testsuites/sptests/spsem01/init.c
> create mode 100644 testsuites/sptests/spsem01/spsem01.doc
> create mode 100644 testsuites/sptests/spsem01/spsem01.scn
>
> diff --git a/testsuites/sptests/Makefile.am b/testsuites/sptests/Makefile.am
> index 4b0fff6..9acf477 100644
> --- a/testsuites/sptests/Makefile.am
> +++ b/testsuites/sptests/Makefile.am
> @@ -25,7 +25,7 @@ SUBDIRS = \
> spintrcritical09 spintrcritical10 spintrcritical11 spintrcritical12 \
> spintrcritical13 spintrcritical14 spintrcritical15 spintrcritical16 \
> spintrcritical17 spintrcritical18 spmkdir spmountmgr01 spheapprot \
> - spsimplesched01 spsimplesched02 spsimplesched03 spnsext01 \
> + spsem01 spsimplesched01 spsimplesched02 spsimplesched03 spnsext01 \
> spedfsched01 spedfsched02 spedfsched03 \
> spcbssched01 spcbssched02 spcbssched03 spqreslib sptimespec01 \
> spatomic01 spatomic02 spatomic03 spatomic04 spatomic05 \
> diff --git a/testsuites/sptests/configure.ac b/testsuites/sptests/configure.ac
> index ba3aa92..9f40fa1 100644
> --- a/testsuites/sptests/configure.ac
> +++ b/testsuites/sptests/configure.ac
> @@ -188,6 +188,7 @@ spprintk/Makefile
> spprivenv01/Makefile
> spqreslib/Makefile
> sprbtree01/Makefile
> +spsem01/Makefile
> spsimplesched01/Makefile
> spsimplesched02/Makefile
> spsimplesched03/Makefile
> diff --git a/testsuites/sptests/spsem01/Makefile.am b/testsuites/sptests/spsem01/Makefile.am
> new file mode 100644
> index 0000000..a957b05
> --- /dev/null
> +++ b/testsuites/sptests/spsem01/Makefile.am
> @@ -0,0 +1,21 @@
> +
> +rtems_tests_PROGRAMS = spsem01
> +spsem01_SOURCES = init.c
> +
> +dist_rtems_tests_DATA = spsem01.scn
> +dist_rtems_tests_DATA += spsem01.doc
> +
> +include $(RTEMS_ROOT)/make/custom/@RTEMS_BSP at .cfg
> +include $(top_srcdir)/../automake/compile.am
> +include $(top_srcdir)/../automake/leaf.am
> +
> +AM_CPPFLAGS += -I$(top_srcdir)/../support/include
> +
> +LINK_OBJS = $(spsem01_OBJECTS)
> +LINK_LIBS = $(spsem01_LDLIBS)
> +
> +spsem01$(EXEEXT): $(spsem01_OBJECTS) $(spsem01_DEPENDENCIES)
> + @rm -f spsem01$(EXEEXT)
> + $(make-exe)
> +
> +include $(top_srcdir)/../automake/local.am
> diff --git a/testsuites/sptests/spsem01/init.c b/testsuites/sptests/spsem01/init.c
> new file mode 100644
> index 0000000..4a123f4
> --- /dev/null
> +++ b/testsuites/sptests/spsem01/init.c
> @@ -0,0 +1,154 @@
> +/*
> + * Copyright (c) 2013 Gedare Bloom.
> + *
> + * The license and distribution terms for this file may be
> + * found in the file LICENSE in this distribution or at
> + * http://www.rtems.com/license/LICENSE.
> + */
> +
> +#include <rtems.h>
> +
> +#include <stdio.h>
> +#include "tmacros.h"
> +
> +/* configuration information */
> +#define CONFIGURE_APPLICATION_NEEDS_CONSOLE_DRIVER
> +#define CONFIGURE_APPLICATION_NEEDS_CLOCK_DRIVER
> +#define CONFIGURE_RTEMS_INIT_TASKS_TABLE
> +#define CONFIGURE_EXTRA_TASK_STACKS (RTEMS_MINIMUM_STACK_SIZE * 3)
> +#define CONFIGURE_MAXIMUM_TASKS 3
> +#define CONFIGURE_MAXIMUM_SEMAPHORES 2
> +#define CONFIGURE_INIT
> +#include <rtems/confdefs.h>
> +
> +rtems_task Task01(rtems_task_argument ignored);
> +rtems_task Task02(rtems_task_argument ignored);
> +rtems_task Init(rtems_task_argument ignored);
> +
> +static int getprio(void)
> +{
> + rtems_status_code status;
> + rtems_task_priority pri;
> +
> + status = rtems_task_set_priority(RTEMS_SELF, RTEMS_CURRENT_PRIORITY, &pri);
> + directive_failed( status, "rtems_task_set_priority");
> + return (int)pri;
> +}
> +
> +rtems_id Task_id[2];
> +rtems_name Task_name[2];
> +
> +rtems_id sem_id[2];
> +rtems_name sem_name[2];
> +
> +rtems_task Init(rtems_task_argument ignored)
> +{
> + rtems_status_code status;
> + rtems_attribute sem_attr;
> +
> + printf("\n*** TEST SEMAPHORE01 ***\n");
> +
> + sem_attr = RTEMS_INHERIT_PRIORITY | RTEMS_BINARY_SEMAPHORE | RTEMS_PRIORITY;
> +
> + sem_name[0] = rtems_build_name( 'S','0',' ',' ');
> + status = rtems_semaphore_create(
> + sem_name[0],
> + 1,
> + sem_attr,
> + 0,
> + &sem_id[0]
> + );
> + directive_failed( status, "rtems_semaphore_create of S0");
> + printf("init: S0 created\n");
> +
> + sem_name[1] = rtems_build_name( 'S','1',' ',' ');
> + status = rtems_semaphore_create(
> + sem_name[1],
> + 1,
> + sem_attr,
> + 0,
> + &sem_id[1]
> + );
> + directive_failed( status, "rtems_semaphore_create of S1");
> + printf("init: S1 created\n");
> +
> + Task_name[0] = rtems_build_name( 'T','A','0','1');
> + status = rtems_task_create(
> + Task_name[0],
> + 36,
> + RTEMS_MINIMUM_STACK_SIZE*2,
> + RTEMS_DEFAULT_MODES,
> + RTEMS_DEFAULT_ATTRIBUTES,
> + &Task_id[0]
> + );
> + directive_failed( status, "rtems_task_create of TA01");
> + printf("init: TA01 created with priority 36\n");
> +
> + Task_name[1] = rtems_build_name( 'T','A','0','2');
> + status = rtems_task_create(
> + Task_name[1],
> + 34,
> + RTEMS_MINIMUM_STACK_SIZE*2,
> + RTEMS_DEFAULT_MODES,
> + RTEMS_DEFAULT_ATTRIBUTES,
> + &Task_id[1]
> + );
> + directive_failed( status , "rtems_task_create of TA02\n");
> + printf("init: TA02 created with priority 34\n");
> +
> + status = rtems_task_start( Task_id[0], Task01, 0);
> + directive_failed( status, "rtems_task_start of TA01");
> +
> + status = rtems_task_delete( RTEMS_SELF);
> + directive_failed( status, "rtems_task_delete of INIT");
> +}
> +
> +/* Task01 starts with priority 36 */
> +rtems_task Task01(rtems_task_argument ignored)
> +{
> + rtems_status_code status;
> + printf("TA01: started with priority %d\n", getprio());
> +
> + status = rtems_semaphore_obtain( sem_id[0], RTEMS_WAIT, 0 );
> + directive_failed( status, "rtems_semaphore_obtain of S0\n");
> + printf("TA01: priority %d, holding S0\n", getprio());
> +
> + status = rtems_semaphore_obtain( sem_id[1], RTEMS_WAIT, 0 );
> + directive_failed( status, "rtems_semaphore_obtain of S1");
> + printf("TA01: priority %d, holding S0, S1\n", getprio());
> +
> + /* Start Task 2 (TA02) with priority 34. It will run immediately. */
> + status = rtems_task_start( Task_id[1], Task02, 0);
> + directive_failed( status, "rtems_task_start of TA02\n");
> +
> + status = rtems_semaphore_release(sem_id[1]);
> + directive_failed( status, "rtems_semaphore_release of S1\n");
> + printf("TA01: priority %d, holding S0\n", getprio());
> +
> + status = rtems_semaphore_release(sem_id[0]);
> + directive_failed( status, "rtems_semaphore_release of S0\n");
> + printf("TA01: priority %d\n", getprio());
> +
> + printf("TA01: exiting\n");
> + printf("*** END OF SEMAPHORE01 ***\n");
> + status = rtems_task_delete( RTEMS_SELF);
> + directive_failed( status, "rtems_task_delete TA01");
> +}
> +
> +/* TA02 starts at Task02 with priority 34 */
> +rtems_task Task02(rtems_task_argument ignored)
> +{
> + rtems_status_code status;
> +
> + printf("TA02: started with priority %d\n", getprio());
> +
> + /* Obtain S1, which should be held by TA01 by now */
> + status = rtems_semaphore_obtain( sem_id[1], RTEMS_WAIT, 0 );
> + directive_failed( status, " rtems_semaphore_obtain S1");
> + printf("TA02: priority %d, holding S1\n", getprio());
> +
> + printf("TA02: exiting\n");
> + status = rtems_task_delete( RTEMS_SELF);
> + directive_failed( status, "rtems_task_delete TA02");
> +}
> +
> diff --git a/testsuites/sptests/spsem01/spsem01.doc b/testsuites/sptests/spsem01/spsem01.doc
> new file mode 100644
> index 0000000..8a09526
> --- /dev/null
> +++ b/testsuites/sptests/spsem01/spsem01.doc
> @@ -0,0 +1,19 @@
> +This test exposes a potential priority inversion when priority inheritance is
> +used and multiple locks are acquired by a low priority task. The scenario
> +consists of 2 tasks of different priority and 2 semaphore/mutexes using
> +priority inheritance. The scenario is:
> +
> +Task 1 has priority 36. Task 2 has priority 34.
> +
> +1. Task 1 obtains semaphore S1.
> +2. Task 1 obtains semaphore S2
> +3. Task 2 preempts Task 1.
> +4. Task 2 blocks on S2. Task 1 inherits priority 34.
> +5. Task 1 resumes. Task 1 releases S2. Task 1 continues to run at priority 34.
> +6. Task 1 releases S1. Task 1 changes priority back to 36.
> +7. Task 2 now preempts Task 1 and begins operating again.
> +
> +During steps 5-6 Task 1 executes when Task 2 should be able to execute.
> +
> +Stepping down the priority of Task 1 when it releases S2 back to its original
> +priority when it obtained S2 fixes the priority inversion.
> diff --git a/testsuites/sptests/spsem01/spsem01.scn b/testsuites/sptests/spsem01/spsem01.scn
> new file mode 100644
> index 0000000..54efd16
> --- /dev/null
> +++ b/testsuites/sptests/spsem01/spsem01.scn
> @@ -0,0 +1,16 @@
> +*** TEST SEMAPHORE01 ***
> +init: S0 created
> +init: S1 created
> +init: TA01 created with priority 36
> +init: TA02 created with priority 34
> +TA01: started with priority 36
> +TA01: priority 36, holding S0
> +TA01: priority 36, holding S0, S1
> +TA02: started with priority 34
> +TA02: priority 34, holding S1
> +TA02: exiting
> +TA01: priority 36, holding S0
> +TA01: priority 36
> +TA01: exiting
> +*** END OF SEMAPHORE01 ***
> +
> --
> 1.7.1
>
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