The current stable LLVM BPF backend fails to compile the BPF selftests
due to a compiler bug. The bug has been fixed in trunk, but that fix
hasn't landed in the binary packages I'm using yet (Fedora arm64).
Without this workaround the tests don't compile for me.
This patch triggers a preprocessor warning on LLVM versions that
definitely have the bug. The test may be conservative (ie, I'm not sure
if 9.1 will have the fix), but it should at least make the current set
of stable releases work together.
See https://reviews.llvm.org/D69438 for more information on the fix. I
obtained the workaround from
https://lore.kernel.org/linux-kselftest/aed8eda7-df20-069b-ea14-f0662898456…
Fixes: 20a9ad2e7136 ("selftests/bpf: add CO-RE relocs array tests")
Signed-off-by: Palmer Dabbelt <palmerdabbelt(a)google.com>
---
.../testing/selftests/bpf/progs/test_core_reloc_arrays.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/tools/testing/selftests/bpf/progs/test_core_reloc_arrays.c b/tools/testing/selftests/bpf/progs/test_core_reloc_arrays.c
index 89951b684282..e5eafdab80a4 100644
--- a/tools/testing/selftests/bpf/progs/test_core_reloc_arrays.c
+++ b/tools/testing/selftests/bpf/progs/test_core_reloc_arrays.c
@@ -43,15 +43,23 @@ int test_core_arrays(void *ctx)
/* in->a[2] */
if (CORE_READ(&out->a2, &in->a[2]))
return 1;
+#if defined(__clang__) && (__clang_major__ < 10) && (__clang_minor__ < 1)
+# warning "clang 9.0 SEGVs on multidimensional arrays, see https://reviews.llvm.org/D69438"
+#else
/* in->b[1][2][3] */
if (CORE_READ(&out->b123, &in->b[1][2][3]))
return 1;
+#endif
/* in->c[1].c */
if (CORE_READ(&out->c1c, &in->c[1].c))
return 1;
+#if defined(__clang__) && (__clang_major__ < 10) && (__clang_minor__ < 1)
+# warning "clang 9.0 SEGVs on multidimensional arrays, see https://reviews.llvm.org/D69438"
+#else
/* in->d[0][0].d */
if (CORE_READ(&out->d00d, &in->d[0][0].d))
return 1;
+#endif
return 0;
}
--
2.25.0.341.g760bfbb309-goog
A few of the lists used in the linked-list KUnit tests (the
for_each_entry{,_reverse} tests) are declared 'static', and so are
not-reinitialised if the test runs multiple times. This was not a
problem when KUnit tests were run once on startup, but when tests are
able to be run manually (e.g. from debugfs[1]), this is no longer the
case.
Making these lists no longer 'static' causes the lists to be
reinitialised, and the test passes each time it is run. While there may
be some value in testing that initialising static lists works, the
for_each_entry_* tests are unlikely to be the right place for it.
Signed-off-by: David Gow <davidgow(a)google.com>
---
lib/list-test.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/lib/list-test.c b/lib/list-test.c
index 76babb1df889..ee09505df16f 100644
--- a/lib/list-test.c
+++ b/lib/list-test.c
@@ -659,7 +659,7 @@ static void list_test_list_for_each_prev_safe(struct kunit *test)
static void list_test_list_for_each_entry(struct kunit *test)
{
struct list_test_struct entries[5], *cur;
- static LIST_HEAD(list);
+ LIST_HEAD(list);
int i = 0;
for (i = 0; i < 5; ++i) {
@@ -680,7 +680,7 @@ static void list_test_list_for_each_entry(struct kunit *test)
static void list_test_list_for_each_entry_reverse(struct kunit *test)
{
struct list_test_struct entries[5], *cur;
- static LIST_HEAD(list);
+ LIST_HEAD(list);
int i = 0;
for (i = 0; i < 5; ++i) {
--
2.25.0.341.g760bfbb309-goog
The reuseport tests currently suffer from a race condition: RST
packets count towards DROP_ERR_SKB_DATA, since they don't contain
a valid struct cmd. Tests will spuriously fail depending on whether
check_results is called before or after the RST is processed.
Exit the BPF program early if FIN is set.
Signed-off-by: Lorenz Bauer <lmb(a)cloudflare.com>
---
.../selftests/bpf/progs/test_select_reuseport_kern.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/tools/testing/selftests/bpf/progs/test_select_reuseport_kern.c b/tools/testing/selftests/bpf/progs/test_select_reuseport_kern.c
index d69a1f2bbbfd..26e77dcc7e91 100644
--- a/tools/testing/selftests/bpf/progs/test_select_reuseport_kern.c
+++ b/tools/testing/selftests/bpf/progs/test_select_reuseport_kern.c
@@ -113,6 +113,12 @@ int _select_by_skb_data(struct sk_reuseport_md *reuse_md)
data_check.skb_ports[0] = th->source;
data_check.skb_ports[1] = th->dest;
+ if (th->fin)
+ /* The connection is being torn down at the end of a
+ * test. It can't contain a cmd, so return early.
+ */
+ return SK_PASS;
+
if ((th->doff << 2) + sizeof(*cmd) > data_check.len)
GOTO_DONE(DROP_ERR_SKB_DATA);
if (bpf_skb_load_bytes(reuse_md, th->doff << 2, &cmd_copy,
--
2.20.1
Currently, there is a lot of false positives if a single reuseport test
fails. This is because expected_results and the result map are not cleared.
Zero both after individual test runs, which fixes the mentioned false
positives.
Signed-off-by: Lorenz Bauer <lmb(a)cloudflare.com>
Fixes: 91134d849a0e ("bpf: Test BPF_PROG_TYPE_SK_REUSEPORT")
---
.../selftests/bpf/prog_tests/select_reuseport.c | 16 ++++++++++++++--
1 file changed, 14 insertions(+), 2 deletions(-)
diff --git a/tools/testing/selftests/bpf/prog_tests/select_reuseport.c b/tools/testing/selftests/bpf/prog_tests/select_reuseport.c
index e7e56929751c..098bcae5f827 100644
--- a/tools/testing/selftests/bpf/prog_tests/select_reuseport.c
+++ b/tools/testing/selftests/bpf/prog_tests/select_reuseport.c
@@ -33,7 +33,7 @@
#define REUSEPORT_ARRAY_SIZE 32
static int result_map, tmp_index_ovr_map, linum_map, data_check_map;
-static enum result expected_results[NR_RESULTS];
+static __u32 expected_results[NR_RESULTS];
static int sk_fds[REUSEPORT_ARRAY_SIZE];
static int reuseport_array = -1, outer_map = -1;
static int select_by_skb_data_prog;
@@ -697,7 +697,19 @@ static void setup_per_test(int type, sa_family_t family, bool inany,
static void cleanup_per_test(bool no_inner_map)
{
- int i, err;
+ int i, err, zero = 0;
+
+ memset(expected_results, 0, sizeof(expected_results));
+
+ for (i = 0; i < NR_RESULTS; i++) {
+ err = bpf_map_update_elem(result_map, &i, &zero, BPF_ANY);
+ RET_IF(err, "reset elem in result_map",
+ "i:%u err:%d errno:%d\n", i, err, errno);
+ }
+
+ err = bpf_map_update_elem(linum_map, &zero, &zero, BPF_ANY);
+ RET_IF(err, "reset line number in linum_map", "err:%d errno:%d\n",
+ err, errno);
for (i = 0; i < REUSEPORT_ARRAY_SIZE; i++)
close(sk_fds[i]);
--
2.20.1
The reuseport tests currently suffer from a race condition: FIN
packets count towards DROP_ERR_SKB_DATA, since they don't contain
a valid struct cmd. Tests will spuriously fail depending on whether
check_results is called before or after the FIN is processed.
Exit the BPF program early if FIN is set.
Signed-off-by: Lorenz Bauer <lmb(a)cloudflare.com>
Fixes: 91134d849a0e ("bpf: Test BPF_PROG_TYPE_SK_REUSEPORT")
---
.../selftests/bpf/progs/test_select_reuseport_kern.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/tools/testing/selftests/bpf/progs/test_select_reuseport_kern.c b/tools/testing/selftests/bpf/progs/test_select_reuseport_kern.c
index d69a1f2bbbfd..26e77dcc7e91 100644
--- a/tools/testing/selftests/bpf/progs/test_select_reuseport_kern.c
+++ b/tools/testing/selftests/bpf/progs/test_select_reuseport_kern.c
@@ -113,6 +113,12 @@ int _select_by_skb_data(struct sk_reuseport_md *reuse_md)
data_check.skb_ports[0] = th->source;
data_check.skb_ports[1] = th->dest;
+ if (th->fin)
+ /* The connection is being torn down at the end of a
+ * test. It can't contain a cmd, so return early.
+ */
+ return SK_PASS;
+
if ((th->doff << 2) + sizeof(*cmd) > data_check.len)
GOTO_DONE(DROP_ERR_SKB_DATA);
if (bpf_skb_load_bytes(reuse_md, th->doff << 2, &cmd_copy,
--
2.20.1