[PATCH AUTOSEL for 4.14 122/161] bpf: fix selftests/bpf test_kmod.sh failure when CONFIG_BPF_JIT_ALWAYS_ON=y

Sasha Levin
2018-04-09T02:58:51Z

From: Yonghong Song <yhs@fb.com>

[ Upstream commit 09584b406742413ac4c8d7e030374d4daa045b69 ]

With CONFIG_BPF_JIT_ALWAYS_ON is defined in the config file,
tools/testing/selftests/bpf/test_kmod.sh failed like below:
[root@localhost bpf]# ./test_kmod.sh
sysctl: setting key "net.core.bpf_jit_enable": Invalid argument
[ JIT enabled:0 hardened:0 ]
[ 132.175681] test_bpf: #297 BPF_MAXINSNS: Jump, gap, jump, ... FAIL to prog_create err=-524 len=4096
[ 132.458834] test_bpf: Summary: 348 PASSED, 1 FAILED, [340/340 JIT'ed]
[ JIT enabled:1 hardened:0 ]
[ 133.456025] test_bpf: #297 BPF_MAXINSNS: Jump, gap, jump, ... FAIL to prog_create err=-524 len=4096
[ 133.730935] test_bpf: Summary: 348 PASSED, 1 FAILED, [340/340 JIT'ed]
[ JIT enabled:1 hardened:1 ]
[ 134.769730] test_bpf: #297 BPF_MAXINSNS: Jump, gap, jump, ... FAIL to prog_create err=-524 len=4096
[ 135.050864] test_bpf: Summary: 348 PASSED, 1 FAILED, [340/340 JIT'ed]
[ JIT enabled:1 hardened:2 ]
[ 136.442882] test_bpf: #297 BPF_MAXINSNS: Jump, gap, jump, ... FAIL to prog_create err=-524 len=4096
[ 136.821810] test_bpf: Summary: 348 PASSED, 1 FAILED, [340/340 JIT'ed]
[root@localhost bpf]#

The test_kmod.sh load/remove test_bpf.ko multiple times with different
settings for sysctl net.core.bpf_jit_{enable,harden}. The failed test #297
of test_bpf.ko is designed such that JIT always fails.

Commit 290af86629b2 (bpf: introduce BPF_JIT_ALWAYS_ON config)
introduced the following tightening logic:
...
if (!bpf_prog_is_dev_bound(fp->aux)) {
fp = bpf_int_jit_compile(fp);
#ifdef CONFIG_BPF_JIT_ALWAYS_ON
if (!fp->jited) {
*err = -ENOTSUPP;
return fp;
}
#endif
...
With this logic, Test #297 always gets return value -ENOTSUPP
when CONFIG_BPF_JIT_ALWAYS_ON is defined, causing the test failure.

This patch fixed the failure by marking Test #297 as expected failure
when CONFIG_BPF_JIT_ALWAYS_ON is defined.

Fixes: 290af86629b2 (bpf: introduce BPF_JIT_ALWAYS_ON config)
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
---
lib/test_bpf.c | 31 ++++++++++++++++++++++++++-----
1 file changed, 26 insertions(+), 5 deletions(-)

diff --git a/lib/test_bpf.c b/lib/test_bpf.c
index 6fbb73f3f531..64701b4c9900 100644
--- a/lib/test_bpf.c
+++ b/lib/test_bpf.c
@@ -83,6 +83,7 @@ struct bpf_test {
__u32 result;
} test[MAX_SUBTESTS];
int (*fill_helper)(struct bpf_test *self);
+ int expected_errcode; /* used when FLAG_EXPECTED_FAIL is set in the aux */
__u8 frag_data[MAX_DATA];
int stack_depth; /* for eBPF only, since tests don't call verifier */
};
@@ -1987,7 +1988,9 @@ static struct bpf_test tests[] = {
},
CLASSIC | FLAG_NO_DATA | FLAG_EXPECTED_FAIL,
{ },
- { }
+ { },
+ .fill_helper = NULL,
+ .expected_errcode = -EINVAL,
},
{
"check: div_k_0",
@@ -1997,7 +2000,9 @@ static struct bpf_test tests[] = {
},
CLASSIC | FLAG_NO_DATA | FLAG_EXPECTED_FAIL,
{ },
- { }
+ { },
+ .fill_helper = NULL,
+ .expected_errcode = -EINVAL,
},
{
"check: unknown insn",
@@ -2008,7 +2013,9 @@ static struct bpf_test tests[] = {
},
CLASSIC | FLAG_EXPECTED_FAIL,
{ },
- { }
+ { },
+ .fill_helper = NULL,
+ .expected_errcode = -EINVAL,
},
{
"check: out of range spill/fill",
@@ -2018,7 +2025,9 @@ static struct bpf_test tests[] = {
},
CLASSIC | FLAG_NO_DATA | FLAG_EXPECTED_FAIL,
{ },
- { }
+ { },
+ .fill_helper = NULL,
+ .expected_errcode = -EINVAL,
},
{
"JUMPS + HOLES",
@@ -2110,6 +2119,8 @@ static struct bpf_test tests[] = {
CLASSIC | FLAG_NO_DATA | FLAG_EXPECTED_FAIL,
{ },
{ },
+ .fill_helper = NULL,
+ .expected_errcode = -EINVAL,
},
{
"check: LDX + RET X",
@@ -2120,6 +2131,8 @@ static struct bpf_test tests[] = {
CLASSIC | FLAG_NO_DATA | FLAG_EXPECTED_FAIL,
{ },
{ },
+ .fill_helper = NULL,
+ .expected_errcode = -EINVAL,
},
{ /* Mainly checking JIT here. */
"M[]: alt STX + LDX",
@@ -2294,6 +2307,8 @@ static struct bpf_test tests[] = {
CLASSIC | FLAG_NO_DATA | FLAG_EXPECTED_FAIL,
{ },
{ },
+ .fill_helper = NULL,
+ .expected_errcode = -EINVAL,
},
{ /* Passes checker but fails during runtime. */
"LD [SKF_AD_OFF-1]",
@@ -5356,6 +5371,7 @@ static struct bpf_test tests[] = {
{ },
{ },
.fill_helper = bpf_fill_maxinsns4,
+ .expected_errcode = -EINVAL,
},
{ /* Mainly checking JIT here. */
"BPF_MAXINSNS: Very long jump",
@@ -5411,10 +5427,15 @@ static struct bpf_test tests[] = {
{
"BPF_MAXINSNS: Jump, gap, jump, ...",
{ },
+#ifdef CONFIG_BPF_JIT_ALWAYS_ON
+ CLASSIC | FLAG_NO_DATA | FLAG_EXPECTED_FAIL,
+#else
CLASSIC | FLAG_NO_DATA,
+#endif
{ },
{ { 0, 0xababcbac } },
.fill_helper = bpf_fill_maxinsns11,
+ .expected_errcode = -ENOTSUPP,
},
{
"BPF_MAXINSNS: ld_abs+get_processor_id",
@@ -6193,7 +6214,7 @@ static struct bpf_prog *generate_filter(int which, int *err)

*err = bpf_prog_create(&fp, &fprog);
if (tests[which].aux & FLAG_EXPECTED_FAIL) {
- if (*err == -EINVAL) {
+ if (*err == tests[which].expected_errcode) {
pr_cont("PASS\n");
/* Verifier rejected filter as expected. */
*err = 0;
--
2.15.1