Patch "bpf: clean up visit_insn()'s instruction processing" has been added to the 6.1-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    bpf: clean up visit_insn()'s instruction processing

to the 6.1-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     bpf-clean-up-visit_insn-s-instruction-processing.patch
and it can be found in the queue-6.1 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 02818dc2580eae9be766e1be3885bdeeeb7ef526
Author: Andrii Nakryiko <andrii@xxxxxxxxxx>
Date:   Thu Mar 2 15:50:04 2023 -0800

    bpf: clean up visit_insn()'s instruction processing
    
    [ Upstream commit 653ae3a874aca6764a4c1f5a8bf1b072ade0d6f4 ]
    
    Instead of referencing processed instruction repeatedly as insns[t]
    throughout entire visit_insn() function, take a local insn pointer and
    work with it in a cleaner way.
    
    It makes enhancing this function further a bit easier as well.
    
    Signed-off-by: Andrii Nakryiko <andrii@xxxxxxxxxx>
    Link: https://lore.kernel.org/r/20230302235015.2044271-7-andrii@xxxxxxxxxx
    Signed-off-by: Alexei Starovoitov <ast@xxxxxxxxxx>
    Stable-dep-of: 3feb263bb516 ("bpf: handle ldimm64 properly in check_cfg()")
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index d1393e07ab2c9..73d500c51bd86 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -11115,44 +11115,43 @@ static int visit_func_call_insn(int t, struct bpf_insn *insns,
  */
 static int visit_insn(int t, struct bpf_verifier_env *env)
 {
-	struct bpf_insn *insns = env->prog->insnsi;
+	struct bpf_insn *insns = env->prog->insnsi, *insn = &insns[t];
 	int ret;
 
-	if (bpf_pseudo_func(insns + t))
+	if (bpf_pseudo_func(insn))
 		return visit_func_call_insn(t, insns, env, true);
 
 	/* All non-branch instructions have a single fall-through edge. */
-	if (BPF_CLASS(insns[t].code) != BPF_JMP &&
-	    BPF_CLASS(insns[t].code) != BPF_JMP32)
+	if (BPF_CLASS(insn->code) != BPF_JMP &&
+	    BPF_CLASS(insn->code) != BPF_JMP32)
 		return push_insn(t, t + 1, FALLTHROUGH, env, false);
 
-	switch (BPF_OP(insns[t].code)) {
+	switch (BPF_OP(insn->code)) {
 	case BPF_EXIT:
 		return DONE_EXPLORING;
 
 	case BPF_CALL:
-		if (insns[t].imm == BPF_FUNC_timer_set_callback)
+		if (insn->imm == BPF_FUNC_timer_set_callback)
 			/* Mark this call insn as a prune point to trigger
 			 * is_state_visited() check before call itself is
 			 * processed by __check_func_call(). Otherwise new
 			 * async state will be pushed for further exploration.
 			 */
 			mark_prune_point(env, t);
-		return visit_func_call_insn(t, insns, env,
-					    insns[t].src_reg == BPF_PSEUDO_CALL);
+		return visit_func_call_insn(t, insns, env, insn->src_reg == BPF_PSEUDO_CALL);
 
 	case BPF_JA:
-		if (BPF_SRC(insns[t].code) != BPF_K)
+		if (BPF_SRC(insn->code) != BPF_K)
 			return -EINVAL;
 
 		/* unconditional jump with single edge */
-		ret = push_insn(t, t + insns[t].off + 1, FALLTHROUGH, env,
+		ret = push_insn(t, t + insn->off + 1, FALLTHROUGH, env,
 				true);
 		if (ret)
 			return ret;
 
-		mark_prune_point(env, t + insns[t].off + 1);
-		mark_jmp_point(env, t + insns[t].off + 1);
+		mark_prune_point(env, t + insn->off + 1);
+		mark_jmp_point(env, t + insn->off + 1);
 
 		return ret;
 
@@ -11164,7 +11163,7 @@ static int visit_insn(int t, struct bpf_verifier_env *env)
 		if (ret)
 			return ret;
 
-		return push_insn(t, t + insns[t].off + 1, BRANCH, env, true);
+		return push_insn(t, t + insn->off + 1, BRANCH, env, true);
 	}
 }