bpf: fix selftests/bpf test_kmod.sh failure when CONFIG_BPF_JIT_ALWAYS_ON=y

Web:        https://git.kernel.org/torvalds/c/09584b406742413ac4c8d7e030374d4daa045b69
Commit:     09584b406742413ac4c8d7e030374d4daa045b69
Parent:     a6b88814ab541d386d793f6df260a3e4d5cccb11
Refname:    refs/heads/master
Author:     Yonghong Song <[email protected]>
AuthorDate: Fri Feb 2 22:37:15 2018 -0800
Committer:  Daniel Borkmann <[email protected]>
CommitDate: Mon Feb 5 00:31:57 2018 +0100

    bpf: fix selftests/bpf test_kmod.sh failure when CONFIG_BPF_JIT_ALWAYS_ON=y
    
    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 <[email protected]>
    Signed-off-by: Daniel Borkmann <[email protected]>
---
 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 4cd9ea9b3449..b4e22345963f 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 */
 };
@@ -2026,7 +2027,9 @@ static struct bpf_test tests[] = {
 		},
 		CLASSIC | FLAG_NO_DATA | FLAG_EXPECTED_FAIL,
 		{ },
-		{ }
+		{ },
+		.fill_helper = NULL,
+		.expected_errcode = -EINVAL,
 	},
 	{
 		"check: div_k_0",
@@ -2036,7 +2039,9 @@ static struct bpf_test tests[] = {
 		},
 		CLASSIC | FLAG_NO_DATA | FLAG_EXPECTED_FAIL,
 		{ },
-		{ }
+		{ },
+		.fill_helper = NULL,
+		.expected_errcode = -EINVAL,
 	},
 	{
 		"check: unknown insn",
@@ -2047,7 +2052,9 @@ static struct bpf_test tests[] = {
 		},
 		CLASSIC | FLAG_EXPECTED_FAIL,
 		{ },
-		{ }
+		{ },
+		.fill_helper = NULL,
+		.expected_errcode = -EINVAL,
 	},
 	{
 		"check: out of range spill/fill",
@@ -2057,7 +2064,9 @@ static struct bpf_test tests[] = {
 		},
 		CLASSIC | FLAG_NO_DATA | FLAG_EXPECTED_FAIL,
 		{ },
-		{ }
+		{ },
+		.fill_helper = NULL,
+		.expected_errcode = -EINVAL,
 	},
 	{
 		"JUMPS + HOLES",
@@ -2149,6 +2158,8 @@ static struct bpf_test tests[] = {
 		CLASSIC | FLAG_NO_DATA | FLAG_EXPECTED_FAIL,
 		{ },
 		{ },
+		.fill_helper = NULL,
+		.expected_errcode = -EINVAL,
 	},
 	{
 		"check: LDX + RET X",
@@ -2159,6 +2170,8 @@ 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",
@@ -2333,6 +2346,8 @@ 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]",
@@ -5395,6 +5410,7 @@ static struct bpf_test tests[] = {
 		{ },
 		{ },
 		.fill_helper = bpf_fill_maxinsns4,
+		.expected_errcode = -EINVAL,
 	},
 	{	/* Mainly checking JIT here. */
 		"BPF_MAXINSNS: Very long jump",
@@ -5450,10 +5466,15 @@ 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",
@@ -6344,7 +6365,7 @@ 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;
--
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