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Mon, 20 Nov 2023 01:06:13 -0800 (PST) Received: from [192.168.1.20] ([178.197.222.11]) by smtp.gmail.com with ESMTPSA id m5-20020a5d6a05000000b0032d2489a399sm10386318wru.49.2023.11.20.01.06.11 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 20 Nov 2023 01:06:12 -0800 (PST) Message-ID: Date: Mon, 20 Nov 2023 10:06:10 +0100 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] nfc: virtual_ncidev: Add variable to check if ndev is running Content-Language: en-US To: bongsu.jeon@samsung.com, Nguyen Dinh Phi Cc: "netdev@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "syzbot+6eb09d75211863f15e3e@syzkaller.appspotmail.com" References: <20231119164705.1991375-1-phind.uet@gmail.com> <20231120044706epcms2p48c4579db14cc4f3274031036caac4718@epcms2p4> From: Krzysztof Kozlowski Autocrypt: addr=krzysztof.kozlowski@linaro.org; keydata= xsFNBFVDQq4BEAC6KeLOfFsAvFMBsrCrJ2bCalhPv5+KQF2PS2+iwZI8BpRZoV+Bd5kWvN79 cFgcqTTuNHjAvxtUG8pQgGTHAObYs6xeYJtjUH0ZX6ndJ33FJYf5V3yXqqjcZ30FgHzJCFUu JMp7PSyMPzpUXfU12yfcRYVEMQrmplNZssmYhiTeVicuOOypWugZKVLGNm0IweVCaZ/DJDIH gNbpvVwjcKYrx85m9cBVEBUGaQP6AT7qlVCkrf50v8bofSIyVa2xmubbAwwFA1oxoOusjPIE J3iadrwpFvsZjF5uHAKS+7wHLoW9hVzOnLbX6ajk5Hf8Pb1m+VH/E8bPBNNYKkfTtypTDUCj NYcd27tjnXfG+SDs/EXNUAIRefCyvaRG7oRYF3Ec+2RgQDRnmmjCjoQNbFrJvJkFHlPeHaeS BosGY+XWKydnmsfY7SSnjAzLUGAFhLd/XDVpb1Een2XucPpKvt9ORF+48gy12FA5GduRLhQU vK4tU7ojoem/G23PcowM1CwPurC8sAVsQb9KmwTGh7rVz3ks3w/zfGBy3+WmLg++C2Wct6nM Pd8/6CBVjEWqD06/RjI2AnjIq5fSEH/BIfXXfC68nMp9BZoy3So4ZsbOlBmtAPvMYX6U8VwD TNeBxJu5Ex0Izf1NV9CzC3nNaFUYOY8KfN01X5SExAoVTr09ewARAQABzTRLcnp5c3p0b2Yg S296bG93c2tpIDxrcnp5c3p0b2Yua296bG93c2tpQGxpbmFyby5vcmc+wsGUBBMBCgA+FiEE m9B+DgxR+NWWd7dUG5NDfTtBYpsFAmI+BxMCGwMFCRRfreEFCwkIBwIGFQoJCAsCBBYCAwEC HgECF4AACgkQG5NDfTtBYptgbhAAjAGunRoOTduBeC7V6GGOQMYIT5n3OuDSzG1oZyM4kyvO XeodvvYv49/ng473E8ZFhXfrre+c1olbr1A8pnz9vKVQs9JGVa6wwr/6ddH7/yvcaCQnHRPK mnXyP2BViBlyDWQ71UC3N12YCoHE2cVmfrn4JeyK/gHCvcW3hUW4i5rMd5M5WZAeiJj3rvYh v8WMKDJOtZFXxwaYGbvFJNDdvdTHc2x2fGaWwmXMJn2xs1ZyFAeHQvrp49mS6PBQZzcx0XL5 cU9ZjhzOZDn6Apv45/C/lUJvPc3lo/pr5cmlOvPq1AsP6/xRXsEFX/SdvdxJ8w9KtGaxdJuf rpzLQ8Ht+H0lY2On1duYhmro8WglOypHy+TusYrDEry2qDNlc/bApQKtd9uqyDZ+rx8bGxyY qBP6bvsQx5YACI4p8R0J43tSqWwJTP/R5oPRQW2O1Ye1DEcdeyzZfifrQz58aoZrVQq+innR aDwu8qDB5UgmMQ7cjDSeAQABdghq7pqrA4P8lkA7qTG+aw8Z21OoAyZdUNm8NWJoQy8m4nUP gmeeQPRc0vjp5JkYPgTqwf08cluqO6vQuYL2YmwVBIbO7cE7LNGkPDA3RYMu+zPY9UUi/ln5 dcKuEStFZ5eqVyqVoZ9eu3RTCGIXAHe1NcfcMT9HT0DPp3+ieTxFx6RjY3kYTGLOwU0EVUNc NAEQAM2StBhJERQvgPcbCzjokShn0cRA4q2SvCOvOXD+0KapXMRFE+/PZeDyfv4dEKuCqeh0 hihSHlaxTzg3TcqUu54w2xYskG8Fq5tg3gm4kh1Gvh1LijIXX99ABA8eHxOGmLPRIBkXHqJY oHtCvPc6sYKNM9xbp6I4yF56xVLmHGJ61KaWKf5KKWYgA9kfHufbja7qR0c6H79LIsiYqf92 H1HNq1WlQpu/fh4/XAAaV1axHFt/dY/2kU05tLMj8GjeQDz1fHas7augL4argt4e+jum3Nwt yupodQBxncKAUbzwKcDrPqUFmfRbJ7ARw8491xQHZDsP82JRj4cOJX32sBg8nO2N5OsFJOcd 5IE9v6qfllkZDAh1Rb1h6DFYq9dcdPAHl4zOj9EHq99/CpyccOh7SrtWDNFFknCmLpowhct9 5ZnlavBrDbOV0W47gO33WkXMFI4il4y1+Bv89979rVYn8aBohEgET41SpyQz7fMkcaZU+ok/ +HYjC/qfDxT7tjKXqBQEscVODaFicsUkjheOD4BfWEcVUqa+XdUEciwG/SgNyxBZepj41oVq FPSVE+Ni2tNrW/e16b8mgXNngHSnbsr6pAIXZH3qFW+4TKPMGZ2rZ6zITrMip+12jgw4mGjy 5y06JZvA02rZT2k9aa7i9dUUFggaanI09jNGbRA/ABEBAAHCwXwEGAEKACYCGwwWIQSb0H4O DFH41ZZ3t1Qbk0N9O0FimwUCYDzvagUJFF+UtgAKCRAbk0N9O0Fim9JzD/0auoGtUu4mgnna oEEpQEOjgT7l9TVuO3Qa/SeH+E0m55y5Fjpp6ZToc481za3xAcxK/BtIX5Wn1mQ6+szfrJQ6 59y2io437BeuWIRjQniSxHz1kgtFECiV30yHRgOoQlzUea7FgsnuWdstgfWi6LxstswEzxLZ Sj1EqpXYZE4uLjh6dW292sO+j4LEqPYr53hyV4I2LPmptPE9Rb9yCTAbSUlzgjiyyjuXhcwM qf3lzsm02y7Ooq+ERVKiJzlvLd9tSe4jRx6Z6LMXhB21fa5DGs/tHAcUF35hSJrvMJzPT/+u /oVmYDFZkbLlqs2XpWaVCo2jv8+iHxZZ9FL7F6AHFzqEFdqGnJQqmEApiRqH6b4jRBOgJ+cY qc+rJggwMQcJL9F+oDm3wX47nr6jIsEB5ZftdybIzpMZ5V9v45lUwmdnMrSzZVgC4jRGXzsU EViBQt2CopXtHtYfPAO5nAkIvKSNp3jmGxZw4aTc5xoAZBLo0OV+Ezo71pg3AYvq0a3/oGRG KQ06ztUMRrj8eVtpImjsWCd0bDWRaaR4vqhCHvAG9iWXZu4qh3ipie2Y0oSJygcZT7H3UZxq fyYKiqEmRuqsvv6dcbblD8ZLkz1EVZL6djImH5zc5x8qpVxlA0A0i23v5QvN00m6G9NFF0Le D2GYIS41Kv4Isx2dEFh+/Q== In-Reply-To: <20231120044706epcms2p48c4579db14cc4f3274031036caac4718@epcms2p4> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 20/11/2023 05:47, Bongsu Jeon wrote: > > On 20/11/2023 01:47, Nguyen Dinh Phi wrote: > >> syzbot reported an memory leak that happens when an skb is add to >> send_buff after virtual nci closed. >> This patch adds a variable to track if the ndev is running before >> handling new skb in send function. >> >> Reported-by: syzbot+6eb09d75211863f15e3e@syzkaller.appspotmail.com >> Closes: https://lore.kernel.org/lkml/00000000000075472b06007df4fb@google.com >> Signed-off-by: Nguyen Dinh Phi >> --- >> drivers/nfc/virtual_ncidev.c | 9 +++++++-- >> 1 file changed, 7 insertions(+), 2 deletions(-) >> >> diff --git a/drivers/nfc/virtual_ncidev.c b/drivers/nfc/virtual_ncidev.c >> index b027be0b0b6f..ac8226db54e2 100644 >> --- a/drivers/nfc/virtual_ncidev.c >> +++ b/drivers/nfc/virtual_ncidev.c >> @@ -20,26 +20,31 @@ >> NFC_PROTO_ISO14443_MASK | \ >> NFC_PROTO_ISO14443_B_MASK | \ >> NFC_PROTO_ISO15693_MASK) >> +#define NCIDEV_RUNNING 0 > This define isn't used. > >> >> struct virtual_nci_dev { >> struct nci_dev *ndev; >> struct mutex mtx; >> struct sk_buff *send_buff; >> struct wait_queue_head wq; >> + bool running; >> }; >> >> static int virtual_nci_open(struct nci_dev *ndev) >> { >> + struct virtual_nci_dev *vdev = nci_get_drvdata(ndev); >> + >> + vdev->running = true; >> return 0; >> } >> >> static int virtual_nci_close(struct nci_dev *ndev) >> { >> struct virtual_nci_dev *vdev = nci_get_drvdata(ndev); >> - >> mutex_lock(&vdev->mtx); >> kfree_skb(vdev->send_buff); >> vdev->send_buff = NULL; >> + vdev->running = false; >> mutex_unlock(&vdev->mtx); >> >> return 0; >> @@ -50,7 +55,7 @@ static int virtual_nci_send(struct nci_dev *ndev, struct sk_buff *skb) >> struct virtual_nci_dev *vdev = nci_get_drvdata(ndev); >> >> mutex_lock(&vdev->mtx); >> - if (vdev->send_buff) { >> + if (vdev->send_buff || !vdev->running) { > > Dear Krzysztof, > > I agree this defensive code. > But i think NFC submodule has to avoid this situation.(calling send function of closed nci_dev) > Could you check this? This code looks not effective. At this point vdev->send_buff is always false, so the additional check would not bring any value. I don't see this fixing anything. Syzbot also does not seem to agree. Nguyen, please test your patches against syzbot *before* sending them. If you claim this fixes the report, please provide me the link to syzbot test results confirming it is fixed. I looked at syzbot dashboard and do not see this issue fixed with this patch. Best regards, Krzysztof