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: 5db58faf989f ("bpf: Add tests for the LRU bpf_htab")
Reported-by: Daniel Borkmann
Signed-off-by: Martin KaFai Lau
---
tools/testing/selftests/bpf/test_lru_map.c | 53 +++---
1 file changed, 27 insertions(+), 26 deletions(-)
diff --git a/tools/testing/selftests/bpf/test_lru_map.c
b/tools/testing/selftests/bpf/test_lru_map.c
index b13fed534d76..9f7bd1915c21 100644
--- a/tools/testing/selftests/bpf/test_lru_map.c
+++ b/tools/testing/selftests/bpf/test_lru_map.c
@@ -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) !
