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From:   Song Liu <song@kernel.org>
To:     <bpf@vger.kernel.org>, <netdev@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>
CC:     <ast@kernel.org>, <daniel@iogearbox.net>, <andrii@kernel.org>,
        <kernel-team@fb.com>, <peterz@infradead.org>, <x86@kernel.org>,
        <iii@linux.ibm.com>, Song Liu <song@kernel.org>
Subject: [PATCH v9 bpf-next 4/9] bpf: use prog->jited_len in  bpf_prog_ksym_set_addr()
Date:   Fri, 4 Feb 2022 10:57:37 -0800
Message-ID: <20220204185742.271030-5-song@kernel.org>
In-Reply-To: <20220204185742.271030-1-song@kernel.org>
References: <20220204185742.271030-1-song@kernel.org>
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Using prog->jited_len is simpler and more accurate than current
estimation (header + header->size).

Also, fix missing prog->jited_len with multi function program. This hasn't
been a real issue before this.

Signed-off-by: Song Liu <song@kernel.org>
---
 kernel/bpf/core.c     | 5 +----
 kernel/bpf/verifier.c | 1 +
 2 files changed, 2 insertions(+), 4 deletions(-)

diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index 14199228a6f0..e3fe53df0a71 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -537,13 +537,10 @@ long bpf_jit_limit_max __read_mostly;
 static void
 bpf_prog_ksym_set_addr(struct bpf_prog *prog)
 {
-	const struct bpf_binary_header *hdr = bpf_jit_binary_hdr(prog);
-	unsigned long addr = (unsigned long)hdr;
-
 	WARN_ON_ONCE(!bpf_prog_ebpf_jited(prog));
 
 	prog->aux->ksym.start = (unsigned long) prog->bpf_func;
-	prog->aux->ksym.end   = addr + hdr->size;
+	prog->aux->ksym.end   = prog->aux->ksym.start + prog->jited_len;
 }
 
 static void
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 1ae41d0cf96c..bbef86cb4e72 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -13067,6 +13067,7 @@ static int jit_subprogs(struct bpf_verifier_env *env)
 
 	prog->jited = 1;
 	prog->bpf_func = func[0]->bpf_func;
+	prog->jited_len = func[0]->jited_len;
 	prog->aux->func = func;
 	prog->aux->func_cnt = env->subprog_cnt;
 	bpf_prog_jit_attempt_done(prog);
-- 
2.30.2