From: Martin KaFai Lau <martin.lau@linux.dev>
To: Amery Hung <amery.hung@bytedance.com>
Cc: bpf@vger.kernel.org, daniel@iogearbox.net, andrii@kernel.org,
alexei.starovoitov@gmail.com, martin.lau@kernel.org,
houtao@huaweicloud.com, davemarchevsky@fb.com,
ameryhung@gmail.com
Subject: Re: [PATCH bpf-next] selftests/bpf: Make sure stashed kptr in local kptr is freed recursively
Date: Wed, 28 Aug 2024 16:38:50 -0700 [thread overview]
Message-ID: <9b57a793-2b30-45bb-bddd-3034c80c1451@linux.dev> (raw)
In-Reply-To: <20240827011301.608620-1-amery.hung@bytedance.com>
On 8/26/24 6:13 PM, Amery Hung wrote:
> When dropping a local kptr, any kptr stashed into it is supposed to be
> freed through bpf_obj_free_fields->__bpf_obj_drop_impl recursively. Add a
> test to make sure it happens.
>
> The test first stashes a referenced kptr to "struct task" into a local
> kptr and gets the reference count of the task. Then, it drops the local
> kptr and reads the reference count of the task again. Since
> bpf_obj_free_fields and __bpf_obj_drop_impl will go through the local kptr
> recursively during bpf_obj_drop, the dtor of the stashed task kptr should
> eventually be called. The second reference count should be one less than
> the first one.
Acked-by: Martin KaFai Lau <martin.lau@kernel.org>
next prev parent reply other threads:[~2024-08-28 23:39 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-08-27 1:13 [PATCH bpf-next] selftests/bpf: Make sure stashed kptr in local kptr is freed recursively Amery Hung
2024-08-28 23:38 ` Martin KaFai Lau [this message]
2024-08-29 19:20 ` patchwork-bot+netdevbpf
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