From: Alexei Starovoitov <alexei.starovoitov@gmail.com>
To: Hou Tao <houtao@huaweicloud.com>
Cc: bpf <bpf@vger.kernel.org>,
Martin KaFai Lau <martin.lau@linux.dev>,
Andrii Nakryiko <andrii@kernel.org>, Song Liu <song@kernel.org>,
Hao Luo <haoluo@google.com>,
Yonghong Song <yonghong.song@linux.dev>,
Daniel Borkmann <daniel@iogearbox.net>,
KP Singh <kpsingh@kernel.org>,
Stanislav Fomichev <sdf@google.com>, Jiri Olsa <jolsa@kernel.org>,
John Fastabend <john.fastabend@gmail.com>,
xingwei lee <xrivendell7@gmail.com>,
Hou Tao <houtao1@huawei.com>
Subject: Re: [PATCH bpf-next 1/4] bpf: Use __GFP_NOWARN for kvcalloc when attaching multiple uprobes
Date: Mon, 11 Dec 2023 08:50:58 -0800 [thread overview]
Message-ID: <CAADnVQKYE7ijTtcWrdsGpTNvS0r-TTXgkw8-R5U7rWTj+-kqAA@mail.gmail.com> (raw)
In-Reply-To: <20231211112843.4147157-2-houtao@huaweicloud.com>
On Mon, Dec 11, 2023 at 3:27 AM Hou Tao <houtao@huaweicloud.com> wrote:
>
> From: Hou Tao <houtao1@huawei.com>
>
> An abnormally big cnt may be passed to link_create.uprobe_multi.cnt,
> and it will trigger the following warning in kvmalloc_node():
>
> if (unlikely(size > INT_MAX)) {
> WARN_ON_ONCE(!(flags & __GFP_NOWARN));
> return NULL;
> }
>
> Fix the warning by using __GFP_NOWARN when invoking kvzalloc() in
> bpf_uprobe_multi_link_attach().
>
> Fixes: 89ae89f53d20 ("bpf: Add multi uprobe link")
> Reported-by: xingwei lee <xrivendell7@gmail.com>
> Closes: https://lore.kernel.org/bpf/CABOYnLwwJY=yFAGie59LFsUsBAgHfroVqbzZ5edAXbFE3YiNVA@mail.gmail.com
> Signed-off-by: Hou Tao <houtao1@huawei.com>
> ---
> kernel/trace/bpf_trace.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
> index 774cf476a892..07b9b5896d6c 100644
> --- a/kernel/trace/bpf_trace.c
> +++ b/kernel/trace/bpf_trace.c
> @@ -3378,7 +3378,7 @@ int bpf_uprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr
> err = -ENOMEM;
>
> link = kzalloc(sizeof(*link), GFP_KERNEL);
> - uprobes = kvcalloc(cnt, sizeof(*uprobes), GFP_KERNEL);
> + uprobes = kvcalloc(cnt, sizeof(*uprobes), GFP_KERNEL | __GFP_NOWARN);
__GFP_NOWARN will hide actual malloc failures.
Let's limit cnt instead. Both for k and u multi probes.
next prev parent reply other threads:[~2023-12-11 16:51 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-12-11 11:28 [PATCH bpf-next 0/4] bpf: Fix warnings in kvmalloc_node() Hou Tao
2023-12-11 11:28 ` [PATCH bpf-next 1/4] bpf: Use __GFP_NOWARN for kvcalloc when attaching multiple uprobes Hou Tao
2023-12-11 12:55 ` Jiri Olsa
2023-12-11 16:50 ` Alexei Starovoitov [this message]
2023-12-12 3:44 ` Hou Tao
2023-12-12 9:54 ` Jiri Olsa
2023-12-12 14:05 ` Hou Tao
2023-12-12 16:58 ` Alexei Starovoitov
2023-12-11 11:28 ` [PATCH bpf-next 2/4] bpf: Use __GFP_NOWARN for kvmalloc_array() when attaching multiple kprobes Hou Tao
2023-12-11 12:56 ` Jiri Olsa
2023-12-11 11:28 ` [PATCH bpf-next 3/4] selftests/bpf: Add test for abnormal cnt during multi-kprobe attachment Hou Tao
2023-12-11 12:56 ` Jiri Olsa
2023-12-11 11:28 ` [PATCH bpf-next 4/4] selftests/bpf: Add test for abnormal cnt during multi-uprobe attachment Hou Tao
2023-12-11 12:56 ` Jiri Olsa
2023-12-12 1:20 ` Hou Tao
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