[PATCH bpf] bpf: offload: reorder offload callback 'prepare' in verifier

From: Yinjun Zhang <redacted>

Commit 4976b718c355 ("bpf: Introduce pseudo_btf_id") switched the
order of resolve_pseudo_ldimm(), in which some pseudo instructions
are rewritten. Thus those rewritten instructions cannot be passed
to driver via 'prepare' offload callback.

Reorder the 'prepare' offload callback to fix it.

Fixes: 4976b718c355 ("bpf: Introduce pseudo_btf_id")
Signed-off-by: Yinjun Zhang <redacted>
Signed-off-by: Simon Horman <redacted>
---
 kernel/bpf/verifier.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index c58598ef4b5b..09849e43f035 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c

@@ -13368,12 +13368,6 @@ int bpf_check(struct bpf_prog **prog, union bpf_attr *attr,
 	if (is_priv)
 		env->test_state_freq = attr->prog_flags & BPF_F_TEST_STATE_FREQ;
 
-	if (bpf_prog_is_dev_bound(env->prog->aux)) {
-		ret = bpf_prog_offload_verifier_prep(env->prog);
-		if (ret)
-			goto skip_full_check;
-	}
-
 	env->explored_states = kvcalloc(state_htab_size(env),
 				       sizeof(struct bpf_verifier_state_list *),
 				       GFP_USER);

@@ -13401,6 +13395,12 @@ int bpf_check(struct bpf_prog **prog, union bpf_attr *attr,
 	if (ret < 0)
 		goto skip_full_check;
 
+	if (bpf_prog_is_dev_bound(env->prog->aux)) {
+		ret = bpf_prog_offload_verifier_prep(env->prog);
+		if (ret)
+			goto skip_full_check;
+	}
+
 	ret = check_cfg(env);
 	if (ret < 0)
 		goto skip_full_check;

-- 
2.20.1

On Thu, May 20, 2021 at 2:01 AM Simon Horman [off-list ref] wrote:

From: Yinjun Zhang <redacted>

Commit 4976b718c355 ("bpf: Introduce pseudo_btf_id") switched the
order of resolve_pseudo_ldimm(), in which some pseudo instructions
are rewritten. Thus those rewritten instructions cannot be passed
to driver via 'prepare' offload callback.

Reorder the 'prepare' offload callback to fix it.

Fixes: 4976b718c355 ("bpf: Introduce pseudo_btf_id")
Signed-off-by: Yinjun Zhang <redacted>
Signed-off-by: Simon Horman <redacted>

Acked-by: Song Liu <redacted>

Hello:

This patch was applied to bpf/bpf.git (refs/heads/master):

On Thu, 20 May 2021 10:58:34 +0200 you wrote:

From: Yinjun Zhang <redacted>

Commit 4976b718c355 ("bpf: Introduce pseudo_btf_id") switched the
order of resolve_pseudo_ldimm(), in which some pseudo instructions
are rewritten. Thus those rewritten instructions cannot be passed
to driver via 'prepare' offload callback.

[...]

Here is the summary with links:
  - [bpf] bpf: offload: reorder offload callback 'prepare' in verifier
    https://git.kernel.org/bpf/bpf/c/ceb11679d9fc

You are awesome, thank you!
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