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From: Martin KaFai Lau <martin.lau@linux.dev>
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>
Subject: Re: [PATCH v3 bpf-next 1/5] bpf: Let callers of btf_parse_kptr() track life cycle of prog btf
Date: Fri, 9 Aug 2024 16:06:02 -0700	[thread overview]
Message-ID: <2f9c21f8-1108-4f12-a06e-58837b53e7fe@linux.dev> (raw)
In-Reply-To: <20240809005131.3916464-2-amery.hung@bytedance.com>

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>'


  reply	other threads:[~2024-08-09 23:06 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-08-09  0:51 [PATCH v3 bpf-next 0/5] Support bpf_kptr_xchg into local kptr Amery Hung
2024-08-09  0:51 ` [PATCH v3 bpf-next 1/5] bpf: Let callers of btf_parse_kptr() track life cycle of prog btf Amery Hung
2024-08-09 23:06   ` Martin KaFai Lau [this message]
2024-08-10  1:29     ` Martin KaFai Lau
2024-08-10 10:14   ` Hou Tao
2024-08-09  0:51 ` [PATCH v3 bpf-next 2/5] bpf: Search for kptrs in prog BTF structs Amery Hung
2024-08-10 10:17   ` Hou Tao
2024-08-09  0:51 ` [PATCH v3 bpf-next 3/5] bpf: Rename ARG_PTR_TO_KPTR -> ARG_KPTR_XCHG_DEST Amery Hung
2024-08-09  0:51 ` [PATCH v3 bpf-next 4/5] bpf: Support bpf_kptr_xchg into local kptr Amery Hung
2024-08-09  0:51 ` [PATCH v3 bpf-next 5/5] selftests/bpf: Test bpf_kptr_xchg stashing " Amery Hung
2024-08-10 10:32   ` Hou Tao

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