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Date:   Sat, 9 Sep 2023 16:59:57 +0800
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Subject: Re: [PATCH bpf-next v5 3/3] bpf, arm64: use bpf_jit_binary_pack_alloc
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To:     Puranjay Mohan <puranjay12@gmail.com>, ast@kernel.org,
        daniel@iogearbox.net, andrii@kernel.org, martin.lau@linux.dev,
        song@kernel.org, catalin.marinas@arm.com, mark.rutland@arm.com,
        bpf@vger.kernel.org, kpsingh@kernel.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org
References: <20230908144320.2474-1-puranjay12@gmail.com>
 <20230908144320.2474-4-puranjay12@gmail.com>
From:   Xu Kuohai <xukuohai@huaweicloud.com>
In-Reply-To: <20230908144320.2474-4-puranjay12@gmail.com>
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On 9/8/2023 10:43 PM, Puranjay Mohan wrote:

[ ... ]

> +
> +void bpf_jit_free(struct bpf_prog *prog)
> +{
> +	if (prog->jited) {
> +		struct arm64_jit_data *jit_data = prog->aux->jit_data;
> +		struct bpf_binary_header *hdr;
> +
> +		/*
> +		 * If we fail the final pass of JIT (from jit_subprogs),
> +		 * the program may not be finalized yet. Call finalize here
> +		 * before freeing it.
> +		 */
> +		if (jit_data) {
> +			bpf_jit_binary_pack_finalize(prog, jit_data->ro_header,
> +						     jit_data->header);

bpf_jit_binary_pack_finalize copies all instructions on the rw image to
the ro_image, which is unnecessary in a free function.

> +			kfree(jit_data);
> +		}
> +		hdr = bpf_jit_binary_pack_hdr(prog);
> +		bpf_jit_binary_pack_free(hdr, NULL);
> +		WARN_ON_ONCE(!bpf_prog_kallsyms_verify_off(prog));
> +	}
> +
> +	bpf_prog_unlock_free(prog);
> +}