Re: [dpdk-dev] [PATCH 1/2] test/rcu: fix array subscript is above array bounds

[Lukasz Wojciechowski <l.wojciechow@partner.samsung.com>]

Hi Honnappa,

If setting value lower than 2 makes no sense as there is no place for 
worker thread, then the patch is perfectly fine

<snip>


>>> When RTE_MAX_LCORE value is small, following compiler errors are
>>> observed.
>>>
>>> ../app/test/test_rcu_qsbr.c:296:54: error: iteration 2 invokes
>>> undefined behavior [-Werror=aggressive-loop-optimizations]
>>>
>>> ../app/test/test_rcu_qsbr.c:315:55: error: array subscript is above
>>> array bounds [-Werror=array-bounds]
>>>
>>> Fixes: b87089b0bb19 ("test/rcu: add API and functional tests")
>>> Cc: stable@dpdk.org
>>>
>>> Signed-off-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
>>> Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
Tested-by: Lukasz Wojciechowski <l.wojciechow@partner.samsung.com>
Reviewed-by: Lukasz Wojciechowski <l.wojciechow@partner.samsung.com>
>>> ---
>>>    app/test/test_rcu_qsbr.c | 56 +++++++++++++++++++++++----------------
>> -
>>>    1 file changed, 33 insertions(+), 23 deletions(-)
>>>
>>> diff --git a/app/test/test_rcu_qsbr.c b/app/test/test_rcu_qsbr.c index
>>> 0a9e5ecd1..848a68092 100644
>>> --- a/app/test/test_rcu_qsbr.c
>>> +++ b/app/test/test_rcu_qsbr.c
>>> @@ -286,13 +286,13 @@ static int
>>>    test_rcu_qsbr_start(void)
>>>    {
>>>    	uint64_t token;
>>> -	int i;
>>> +	unsigned int i;
>>>
>>>    	printf("\nTest rte_rcu_qsbr_start()\n");
>>>
>>>    	rte_rcu_qsbr_init(t[0], RTE_MAX_LCORE);
>>>
>>> -	for (i = 0; i < 3; i++)
>>> +	for (i = 0; i < num_cores; i++)
>>>    		rte_rcu_qsbr_thread_register(t[0], enabled_core_ids[i]);
>>>
>>>    	token = rte_rcu_qsbr_start(t[0]);
>>> @@ -306,14 +306,18 @@ test_rcu_qsbr_check_reader(void *arg)
>>>    {
>>>    	struct rte_rcu_qsbr *temp;
>>>    	uint8_t read_type = (uint8_t)((uintptr_t)arg);
>>> +	unsigned int i;
>>>
>>>    	temp = t[read_type];
>>>
>>>    	/* Update quiescent state counter */
>>> -	rte_rcu_qsbr_quiescent(temp, enabled_core_ids[0]);
>>> -	rte_rcu_qsbr_quiescent(temp, enabled_core_ids[1]);
>>> -	rte_rcu_qsbr_thread_unregister(temp, enabled_core_ids[2]);
>>> -	rte_rcu_qsbr_quiescent(temp, enabled_core_ids[3]);
>>> +	for (i = 0; i < num_cores; i++) {
>>> +		if (i % 2 == 0)
>>> +			rte_rcu_qsbr_quiescent(temp, enabled_core_ids[i]);
>>> +		else
>>> +			rte_rcu_qsbr_thread_unregister(temp,
>>> +							enabled_core_ids[i]);
>>> +	}
>>>    	return 0;
>>>    }
>>>
>>> @@ -324,7 +328,8 @@ test_rcu_qsbr_check_reader(void *arg)
>>>    static int
>>>    test_rcu_qsbr_check(void)
>>>    {
>>> -	int i, ret;
>>> +	int ret;
>>> +	unsigned int i;
>>>    	uint64_t token;
>>>
>>>    	printf("\nTest rte_rcu_qsbr_check()\n"); @@ -342,7 +347,7 @@
>>> test_rcu_qsbr_check(void)
>>>    	ret = rte_rcu_qsbr_check(t[0], token, true);
>>>    	TEST_RCU_QSBR_RETURN_IF_ERROR((ret == 0), "Blocking QSBR
>> check");
>>> -	for (i = 0; i < 3; i++)
>>> +	for (i = 0; i < num_cores; i++)
>>>    		rte_rcu_qsbr_thread_register(t[0], enabled_core_ids[i]);
>>>
>>>    	ret = rte_rcu_qsbr_check(t[0], token, false); @@ -357,7 +362,7 @@
>>> test_rcu_qsbr_check(void)
>>>    	/* Threads are offline, hence this should pass */
>>>    	TEST_RCU_QSBR_RETURN_IF_ERROR((ret == 0), "Non-blocking QSBR
>>> check");
>>>
>>> -	for (i = 0; i < 3; i++)
>>> +	for (i = 0; i < num_cores; i++)
>>>    		rte_rcu_qsbr_thread_unregister(t[0], enabled_core_ids[i]);
>>>
>>>    	ret = rte_rcu_qsbr_check(t[0], token, true); @@ -365,7 +370,7 @@
>>> test_rcu_qsbr_check(void)
>>>
>>>    	rte_rcu_qsbr_init(t[0], RTE_MAX_LCORE);
>>>
>>> -	for (i = 0; i < 4; i++)
>>> +	for (i = 0; i < num_cores; i++)
>>>    		rte_rcu_qsbr_thread_register(t[0], enabled_core_ids[i]);
>>>
>>>    	token = rte_rcu_qsbr_start(t[0]);
>>> @@ -928,7 +933,7 @@ test_rcu_qsbr_dq_functional(int32_t size, int32_t
>> esize, uint32_t flags)
>>>    static int
>>>    test_rcu_qsbr_dump(void)
>>>    {
>>> -	int i;
>>> +	unsigned int i;
>>>
>>>    	printf("\nTest rte_rcu_qsbr_dump()\n");
>>>
>>> @@ -945,7 +950,7 @@ test_rcu_qsbr_dump(void)
>>>
>>>    	rte_rcu_qsbr_thread_register(t[0], enabled_core_ids[0]);
>>>
>>> -	for (i = 1; i < 3; i++)
>>> +	for (i = 1; i < num_cores; i++)
>>>    		rte_rcu_qsbr_thread_register(t[1], enabled_core_ids[i]);
>>>
>>>    	rte_rcu_qsbr_dump(stdout, t[0]);
>>> @@ -1095,7 +1100,7 @@ test_rcu_qsbr_sw_sv_3qs(void)
>>>    {
>>>    	uint64_t token[3];
>>>    	uint32_t c;
>>> -	int i;
>>> +	int i, num_readers;
>>>    	int32_t pos[3];
>>>
>>>    	writer_done = 0;
>>> @@ -1118,7 +1123,11 @@ test_rcu_qsbr_sw_sv_3qs(void)
>>>    	thread_info[0].ih = 0;
>>>
>>>    	/* Reader threads are launched */
>>> -	for (i = 0; i < 4; i++)
>>> +	/* Keep the number of reader threads low to reduce
>>> +	 * the execution time.
>>> +	 */
>>> +	num_readers = num_cores < 4 ? num_cores : 4;
>>> +	for (i = 0; i < num_readers; i++)
>>>    		rte_eal_remote_launch(test_rcu_qsbr_reader,
>> &thread_info[0],
>>>    					enabled_core_ids[i]);
>>>
>>> @@ -1151,7 +1160,7 @@ test_rcu_qsbr_sw_sv_3qs(void)
>>>
>>>    	/* Check the quiescent state status */
>>>    	rte_rcu_qsbr_check(t[0], token[0], true);
>>> -	for (i = 0; i < 4; i++) {
>>> +	for (i = 0; i < num_readers; i++) {
>>>    		c = hash_data[0][0][enabled_core_ids[i]];
>>>    		if (c != COUNTER_VALUE && c != 0) {
>>>    			printf("Reader lcore %d did not complete #0 = %d\n",
>> @@ -1169,7
>>> +1178,7 @@ test_rcu_qsbr_sw_sv_3qs(void)
>>>
>>>    	/* Check the quiescent state status */
>>>    	rte_rcu_qsbr_check(t[0], token[1], true);
>>> -	for (i = 0; i < 4; i++) {
>>> +	for (i = 0; i < num_readers; i++) {
>>>    		c = hash_data[0][3][enabled_core_ids[i]];
>>>    		if (c != COUNTER_VALUE && c != 0) {
>>>    			printf("Reader lcore %d did not complete #3 = %d\n",
>> @@ -1187,7
>>> +1196,7 @@ test_rcu_qsbr_sw_sv_3qs(void)
>>>
>>>    	/* Check the quiescent state status */
>>>    	rte_rcu_qsbr_check(t[0], token[2], true);
>>> -	for (i = 0; i < 4; i++) {
>>> +	for (i = 0; i < num_readers; i++) {
>>>    		c = hash_data[0][6][enabled_core_ids[i]];
>>>    		if (c != COUNTER_VALUE && c != 0) {
>>>    			printf("Reader lcore %d did not complete #6 = %d\n",
>> @@ -1206,7
>>> +1215,7 @@ test_rcu_qsbr_sw_sv_3qs(void)
>>>    	writer_done = 1;
>>>
>>>    	/* Wait and check return value from reader threads */
>>> -	for (i = 0; i < 4; i++)
>>> +	for (i = 0; i < num_readers; i++)
>>>    		if (rte_eal_wait_lcore(enabled_core_ids[i]) < 0)
>>>    			goto error;
>>>    	rte_hash_free(h[0]);
>>> @@ -1236,6 +1245,12 @@ test_rcu_qsbr_mw_mv_mqs(void)
>>>    	unsigned int i, j;
>>>    	unsigned int test_cores;
>>>
>>> +	if (RTE_MAX_LCORE < 5 || num_cores < 4) {
>>> +		printf("Not enough cores for %s, expecting at least 5\n",
>>> +			__func__);
>>> +		return TEST_SKIPPED;
>>> +	}
>>> +
>>>    	writer_done = 0;
>>>    	test_cores = num_cores / 4;
>>>    	test_cores = test_cores * 4;
>>> @@ -1321,11 +1336,6 @@ test_rcu_qsbr_main(void)
>>>    {
>>>    	uint16_t core_id;
>>>
>>> -	if (rte_lcore_count() < 5) {
>>> -		printf("Not enough cores for rcu_qsbr_autotest, expecting at
>> least 5\n");
>>> -		return TEST_SKIPPED;
>>> -	}
>>> -
>>>    	num_cores = 0;
>>>    	RTE_LCORE_FOREACH_SLAVE(core_id) {
>>>    		enabled_core_ids[num_cores] = core_id;
>> --
>> Lukasz Wojciechowski
>> Principal Software Engineer
>>
>> Samsung R&D Institute Poland
>> Samsung Electronics
>> Office +48 22 377 88 25
>> l.wojciechow@partner.samsung.com

-- 
Lukasz Wojciechowski
Principal Software Engineer

Samsung R&D Institute Poland
Samsung Electronics
Office +48 22 377 88 25
l.wojciechow@partner.samsung.com