Re: [PATCH bpf 1/2] bpf: support PTR_TO_MEM{,_OR_NULL} register spilling

On Tue, Jan 12, 2021 at 3:24 PM Gilad Reti [off-list ref] wrote:

On Tue, Jan 12, 2021 at 3:57 PM KP Singh [off-list ref] wrote:

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On Tue, Jan 12, 2021 at 10:14 AM Gilad Reti [off-list ref] wrote:

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Add support for pointer to mem register spilling, to allow the verifier
to track pointer to valid memory addresses. Such pointers are returned

nit: pointers

Thanks

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for example by a successful call of the bpf_ringbuf_reserve helper.

This patch was suggested as a solution by Yonghong Song.

You can use the "Suggested-by:" tag for this.

Thanks

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The patch was partially contibuted by CyberArk Software, Inc.

nit: typo *contributed

Thanks. Should I submit a v2 of the patch to correct all of those?

I think it would be nice to do another revision
which also addresses the comments on the other patch.

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Also, I was wondering if "partially" here means someone collaborated with you
on the patch? And, in that case:

"Co-developed-by:" would be a better tag here.

No, I did it alone. I mentioned CyberArk since I work there and did some of the
coding during my daily work, so they deserve credit.

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Acked-by: KP Singh <kpsingh@kernel.org>

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Fixes: 457f44363a88 ("bpf: Implement BPF ring buffer and verifier
support for it")
Signed-off-by: Gilad Reti <redacted>
---
 kernel/bpf/verifier.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 17270b8404f1..36af69fac591 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c

@@ -2217,6 +2217,8 @@ static bool is_spillable_regtype(enum bpf_reg_type type)
        case PTR_TO_RDWR_BUF:
        case PTR_TO_RDWR_BUF_OR_NULL:
        case PTR_TO_PERCPU_BTF_ID:
+       case PTR_TO_MEM:
+       case PTR_TO_MEM_OR_NULL:
                return true;
        default:
                return false;
--

2.27.0