2024-03-21 00:30:48

by Harishankar Vishwanathan

Subject: [PATCH] bpf-next: Avoid goto in regs_refine_cond_op()

In case of GE/GT/SGE/JST instructions, regs_refine_cond_op()
reuses the logic that does analysis of LE/LT/SLE/SLT instructions.
This commit avoids the use of a goto to perform the reuse.

Signed-off-by: Harishankar Vishwanathan <[email protected]>
---
kernel/bpf/verifier.c | 22 +++++++++++++---------
1 file changed, 13 insertions(+), 9 deletions(-)

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index de7813947981..ca6cacf7b42f 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -14544,7 +14544,19 @@ static void regs_refine_cond_op(struct bpf_reg_state *reg1, struct bpf_reg_state
struct tnum t;
u64 val;

-again:
+ /* In case of GE/GT/SGE/JST, reuse LE/LT/SLE/SLT logic from below */
+ switch (opcode) {
+ case BPF_JGE:
+ case BPF_JGT:
+ case BPF_JSGE:
+ case BPF_JSGT:
+ opcode = flip_opcode(opcode);
+ swap(reg1, reg2);
+ break;
+ default:
+ break;
+ }
+
switch (opcode) {
case BPF_JEQ:
if (is_jmp32) {
@@ -14687,14 +14699,6 @@ static void regs_refine_cond_op(struct bpf_reg_state *reg1, struct bpf_reg_state
reg2->smin_value = max(reg1->smin_value + 1, reg2->smin_value);
}
break;
- case BPF_JGE:
- case BPF_JGT:
- case BPF_JSGE:
- case BPF_JSGT:
- /* just reuse LE/LT logic above */
- opcode = flip_opcode(opcode);
- swap(reg1, reg2);
- goto again;
default:
return;
}
--
2.40.1

2024-03-21 19:00:38

by patchwork-bot+netdevbpf

Subject: Re: [PATCH] bpf-next: Avoid goto in regs_refine_cond_op()

Hello:

This patch was applied to bpf/bpf-next.git (master)
by Andrii Nakryiko <[email protected]>:

On Wed, 20 Mar 2024 20:29:54 -0400 you wrote:
> In case of GE/GT/SGE/JST instructions, regs_refine_cond_op()
> reuses the logic that does analysis of LE/LT/SLE/SLT instructions.
> This commit avoids the use of a goto to perform the reuse.
>
> Signed-off-by: Harishankar Vishwanathan <[email protected]>
> ---
> kernel/bpf/verifier.c | 22 +++++++++++++---------
> 1 file changed, 13 insertions(+), 9 deletions(-)

Here is the summary with links:
- bpf-next: Avoid goto in regs_refine_cond_op()
https://git.kernel.org/bpf/bpf-next/c/4c2a26fc80bc

You are awesome, thank you!
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