Re: [PATCH] Signed-off-by: giladreti <gilad.reti@gmail.com>

On Mon, Jan 11, 2021 at 8:06 AM Gilad Reti [off-list ref] wrote:

On Mon, Jan 11, 2021, 17:55 Daniel Borkmann [off-list ref] wrote:

quoted

Hello Gilad,

On 1/11/21 4:31 PM, giladreti wrote:

quoted

Added support for pointer to mem register spilling, to allow the verifier
to track pointer to valid memory addresses. Such pointers are returned
for example by a successful call of the bpf_ringbuf_reserve helper.

This patch was suggested as a solution by Yonghong Song.

The SoB should not be in subject line but as part of the commit message instead
and with proper name, e.g.

Signed-off-by: Gilad Reti <redacted>

For subject line, please use a short summary that fits the patch prefixed with
the subsystem "bpf: [...]", see also [0] as an example. Thanks.

It would be good if you could also add a BPF selftest for this [1].

   [0] https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git/commit/?id=e22d7f05e445165e58feddb4e40cc9c0f94453bc
   [1] https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git/tree/tools/testing/selftests/bpf/
       https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git/tree/tools/testing/selftests/bpf/verifier/spill_fill.c

Sure. Thanks for your guidance. As you can probably tell, I am new to
kernel code contribution (in fact this is a first time for me).
Should I try to submit this patch again?

In addition to all already mentioned things, also make sure you have
[PATCH bpf] prefix in the subject, to identify that this is a bug fix
for the bpf tree.

Also you missed adding Fixes tag, please add this:

Fixes: 457f44363a88 ("bpf: Implement BPF ring buffer and verifier
support for it")

And yes, please re-submit with all the feedback incorporated
(including the selftest).

Sorry in advance for all the overhead I may be causing to you...

quoted

quoted

---
  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;