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Date:   Mon, 11 Jan 2021 17:31:23 +0200
From:   giladreti <gilad.reti@gmail.com>
To:     bpf@vger.kernel.org, Yonghong Song <yhs@fb.com>
Cc:     Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: [PATCH] Signed-off-by: giladreti <gilad.reti@gmail.com>
Message-ID: <20210111153123.GA423936@ubuntu>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
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Precedence: bulk

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.
---
 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