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bpf: Fix test_lru_sanity5() in test_lru_map.c

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test_lru_sanity5() fails when the number of online cpus
is fewer than the number of possible cpus.  It can be
reproduced with qemu by using cmd args "--smp cpus=2,maxcpus=8".

The problem is the loop in test_lru_sanity5() is testing
'i' which is incorrect.

This patch:
1. Make sched_next_online() always return -1 if it cannot
   find a next cpu to schedule the process.
2. In test_lru_sanity5(), the parent process does
   sched_setaffinity() first (through sched_next_online())
   and the forked process will inherit it according to
   the 'man sched_setaffinity'.

Fixes: 5db58faf98 ("bpf: Add tests for the LRU bpf_htab")
Reported-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Martin KaFai Lau 2017-01-16 22:17:29 -08:00 committed by David S. Miller
parent d5ff72d9af
commit 3fbfadce60
1 changed files with 27 additions and 26 deletions
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53
tools/testing/selftests/bpf/test_lru_map.c
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@ -67,21 +67,23 @@ static int map_equal(int lru_map, int expected)
return map_subset(lru_map, expected) && map_subset(expected, lru_map);
}
static int sched_next_online(int pid, int next_to_try)
static int sched_next_online(int pid, int *next_to_try)
{
cpu_set_t cpuset;
int next = *next_to_try;
int ret = -1;
if (next_to_try == nr_cpus)
return -1;
while (next_to_try < nr_cpus) {
while (next < nr_cpus) {
CPU_ZERO(&cpuset);
CPU_SET(next_to_try++, &cpuset);
if (!sched_setaffinity(pid, sizeof(cpuset), &cpuset))
CPU_SET(next++, &cpuset);
if (!sched_setaffinity(pid, sizeof(cpuset), &cpuset)) {
ret = 0;
break;
}
}
return next_to_try;
*next_to_try = next;
return ret;
}
/* Size of the LRU amp is 2
@ -96,11 +98,12 @@ static void test_lru_sanity0(int map_type, int map_flags)
{
unsigned long long key, value[nr_cpus];
int lru_map_fd, expected_map_fd;
int next_cpu = 0;
printf("%s (map_type:%d map_flags:0x%X): ", __func__, map_type,
map_flags);
assert(sched_next_online(0, 0) != -1);
assert(sched_next_online(0, &next_cpu) != -1);
if (map_flags & BPF_F_NO_COMMON_LRU)
lru_map_fd = create_map(map_type, map_flags, 2 * nr_cpus);
@ -183,6 +186,7 @@ static void test_lru_sanity1(int map_type, int map_flags, unsigned int tgt_free)
int lru_map_fd, expected_map_fd;
unsigned int batch_size;
unsigned int map_size;
int next_cpu = 0;
if (map_flags & BPF_F_NO_COMMON_LRU)
/* Ther percpu lru list (i.e each cpu has its own LRU
@ -196,7 +200,7 @@ static void test_lru_sanity1(int map_type, int map_flags, unsigned int tgt_free)
printf("%s (map_type:%d map_flags:0x%X): ", __func__, map_type,
map_flags);
assert(sched_next_online(0, 0) != -1);
assert(sched_next_online(0, &next_cpu) != -1);
batch_size = tgt_free / 2;
assert(batch_size * 2 == tgt_free);
@ -262,6 +266,7 @@ static void test_lru_sanity2(int map_type, int map_flags, unsigned int tgt_free)
int lru_map_fd, expected_map_fd;
unsigned int batch_size;
unsigned int map_size;
int next_cpu = 0;
if (map_flags & BPF_F_NO_COMMON_LRU)
/* Ther percpu lru list (i.e each cpu has its own LRU
@ -275,7 +280,7 @@ static void test_lru_sanity2(int map_type, int map_flags, unsigned int tgt_free)
printf("%s (map_type:%d map_flags:0x%X): ", __func__, map_type,
map_flags);
assert(sched_next_online(0, 0) != -1);
assert(sched_next_online(0, &next_cpu) != -1);
batch_size = tgt_free / 2;
assert(batch_size * 2 == tgt_free);
@ -370,11 +375,12 @@ static void test_lru_sanity3(int map_type, int map_flags, unsigned int tgt_free)
int lru_map_fd, expected_map_fd;
unsigned int batch_size;
unsigned int map_size;
int next_cpu = 0;
printf("%s (map_type:%d map_flags:0x%X): ", __func__, map_type,
map_flags);
assert(sched_next_online(0, 0) != -1);
assert(sched_next_online(0, &next_cpu) != -1);
batch_size = tgt_free / 2;
assert(batch_size * 2 == tgt_free);
@ -430,11 +436,12 @@ static void test_lru_sanity4(int map_type, int map_flags, unsigned int tgt_free)
int lru_map_fd, expected_map_fd;
unsigned long long key, value[nr_cpus];
unsigned long long end_key;
int next_cpu = 0;
printf("%s (map_type:%d map_flags:0x%X): ", __func__, map_type,
map_flags);
assert(sched_next_online(0, 0) != -1);
assert(sched_next_online(0, &next_cpu) != -1);
if (map_flags & BPF_F_NO_COMMON_LRU)
lru_map_fd = create_map(map_type, map_flags,
@ -502,9 +509,8 @@ static void do_test_lru_sanity5(unsigned long long last_key, int map_fd)
static void test_lru_sanity5(int map_type, int map_flags)
{
unsigned long long key, value[nr_cpus];
int next_sched_cpu = 0;
int next_cpu = 0;
int map_fd;
int i;
if (map_flags & BPF_F_NO_COMMON_LRU)
return;
@ -519,27 +525,20 @@ static void test_lru_sanity5(int map_type, int map_flags)
key = 0;
assert(!bpf_map_update(map_fd, &key, value, BPF_NOEXIST));
for (i = 0; i < nr_cpus; i++) {
while (sched_next_online(0, &next_cpu) != -1) {
pid_t pid;
pid = fork();
if (pid == 0) {
next_sched_cpu = sched_next_online(0, next_sched_cpu);
if (next_sched_cpu != -1)
do_test_lru_sanity5(key, map_fd);
do_test_lru_sanity5(key, map_fd);
exit(0);
} else if (pid == -1) {
printf("couldn't spawn #%d process\n", i);
printf("couldn't spawn process to test key:%llu\n",
key);
exit(1);
} else {
int status;
/* It is mostly redundant and just allow the parent
* process to update next_shced_cpu for the next child
* process
*/
next_sched_cpu = sched_next_online(pid, next_sched_cpu);
assert(waitpid(pid, &status, 0) == pid);
assert(status == 0);
key++;
@ -547,6 +546,8 @@ static void test_lru_sanity5(int map_type, int map_flags)
}
close(map_fd);
/* At least one key should be tested */
assert(key > 0);
printf("Pass\n");
}