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Date: Fri, 9 Aug 2024 16:06:02 -0700
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Subject: Re: [PATCH v3 bpf-next 1/5] bpf: Let callers of btf_parse_kptr()
 track life cycle of prog btf
To: Amery Hung <ameryhung@gmail.com>
Cc: bpf@vger.kernel.org, daniel@iogearbox.net, andrii@kernel.org,
 alexei.starovoitov@gmail.com, martin.lau@kernel.org, houtao@huaweicloud.com,
 sinquersw@gmail.com, davemarchevsky@fb.com,
 Amery Hung <amery.hung@bytedance.com>
References: <20240809005131.3916464-1-amery.hung@bytedance.com>
 <20240809005131.3916464-2-amery.hung@bytedance.com>
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From: Martin KaFai Lau <martin.lau@linux.dev>
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On 8/8/24 5:51 PM, Amery Hung wrote:
> btf_parse_kptr() and btf_record_free() do btf_get() and btf_put()
> respectively when working on btf_record in program and map if there are
> kptr fields. If the kptr is from program BTF, since both callers has
> already tracked the life cycle of program BTF, it is safe to remove the
> btf_get() and btf_put().
> 
> This change prevents memory leak of program BTF later when we start
> searching for kptr fields when building btf_record for program. It can
> happen when the btf fd is closed. The btf_put() corresponding to the
> btf_get() in btf_parse_kptr() was supposed to be called by
> btf_record_free() in btf_free_struct_meta_tab() in btf_free(). However,
> it will never happen since the invocation of btf_free() depends on the
> refcount of the btf to become 0 in the first place.
> 
> Signed-off-by: Amery Hung <amery.hung@bytedance.com>

Acked-by: Martin KaFai Lau <martin.lau@kernel.org>

Need to fix the checkpatch warning though:

WARNING: From:/Signed-off-by: email address mismatch: 'From: Amery Hung 
<ameryhung@gmail.com>' != 'Signed-off-by: Amery Hung <amery.hung@bytedance.com>'