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AJvYcCU96U7pFi1DtlCbEaBb6ShFJH5Axrr3TTtCIjLg/Fi+lYegy9+KcDi7k2U7Wd+vpzgNnT4=@vger.kernel.org, AJvYcCX+pN7TWtONnhf+z/S1xxKfHp0AI2ttmQgbGN3mpza/IAGvICGfBmj838bnQ4TxdLREIoiZ7MelEGkfsoS8@vger.kernel.org X-Gm-Message-State: AOJu0YxSLaSGzBWFnX+nQdTtXbFDeLXxj70/nYmij0K2gTNl8opwHquS moelpWok/V4t5NCwVDAIgytLrBupI/3PKba5s78UyfMy3qEyi8Cr X-Google-Smtp-Source: AGHT+IGGDuBgh+TS1hY/fAwTnpxC3Kw2QtydmXz6gxJ8uIjXvwXZzVJU+o685Z5ZtifuYntuM3qD2A== X-Received: by 2002:a05:6a21:4a41:b0:1c8:92ed:7c5e with SMTP id adf61e73a8af0-1cf2acabd28mr14573841637.23.1725935760620; Mon, 09 Sep 2024 19:36:00 -0700 (PDT) Received: from [172.23.160.213] ([183.134.211.54]) by smtp.gmail.com with ESMTPSA id 41be03b00d2f7-7d82373635esm4570811a12.13.2024.09.09.19.35.57 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 09 Sep 2024 19:36:00 -0700 (PDT) Message-ID: Date: Tue, 10 Sep 2024 10:35:51 +0800 Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [v2 PATCH bpf-next 1/2] bpf: Check percpu map value size first To: Andrii Nakryiko Cc: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Eduard Zingerman , Song Liu , Hou Tao , Yonghong Song , John Fastabend , KP Singh , Stanislav Fomichev , bpf@vger.kernel.org, linux-kernel@vger.kernel.org, jinke han References: <20240909071346.1300093-1-chen.dylane@gmail.com> <20240909071346.1300093-2-chen.dylane@gmail.com> From: Tao Chen In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit 在 2024/9/10 04:17, Andrii Nakryiko 写道: > On Mon, Sep 9, 2024 at 12:14 AM Tao Chen wrote: >> >> Percpu map is often used, but the map value size limit often ignored, >> like issue: https://github.com/iovisor/bcc/issues/2519. Actually, >> percpu map value size is bound by PCPU_MIN_UNIT_SIZE, so we >> can check the value size whether it exceeds PCPU_MIN_UNIT_SIZE first, >> like percpu map of local_storage. Maybe the error message seems clearer >> compared with "cannot allocate memory". >> >> Signed-off-by: Tao Chen >> Signed-off-by: jinke han > > names in SOB should be capitalized Hi Andrii，thank you for your attention, i will change it. > > the check is useful, so: > > Acked-by: Andrii Nakryiko > >> --- >> kernel/bpf/arraymap.c | 3 +++ >> kernel/bpf/hashtab.c | 3 +++ >> 2 files changed, 6 insertions(+) >> >> diff --git a/kernel/bpf/arraymap.c b/kernel/bpf/arraymap.c >> index a43e62e2a8bb..79660e3fca4c 100644 >> --- a/kernel/bpf/arraymap.c >> +++ b/kernel/bpf/arraymap.c >> @@ -73,6 +73,9 @@ int array_map_alloc_check(union bpf_attr *attr) >> /* avoid overflow on round_up(map->value_size) */ >> if (attr->value_size > INT_MAX) >> return -E2BIG; >> + /* percpu map value size is bound by PCPU_MIN_UNIT_SIZE */ >> + if (percpu && round_up(attr->value_size, 8) > PCPU_MIN_UNIT_SIZE) >> + return -E2BIG; >> >> return 0; >> } >> diff --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c >> index 45c7195b65ba..b14b87463ee0 100644 >> --- a/kernel/bpf/hashtab.c >> +++ b/kernel/bpf/hashtab.c >> @@ -462,6 +462,9 @@ static int htab_map_alloc_check(union bpf_attr *attr) >> * kmalloc-able later in htab_map_update_elem() >> */ >> return -E2BIG; >> + /* percpu map value size is bound by PCPU_MIN_UNIT_SIZE */ >> + if (percpu && round_up(attr->value_size, 8) > PCPU_MIN_UNIT_SIZE) >> + return -E2BIG; >> >> return 0; >> } >> -- >> 2.25.1 >> -- Best Regards Dylane Chen