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Sat, 19 Sep 2026 12:23:38 -0700 (PDT) Received: from fedora ([202.47.63.86]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-4872456325esm9213088f8f.15.2026.09.19.12.23.36 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 19 Sep 2026 12:23:37 -0700 (PDT) From: Muhammad Bilal To: mchehab@kernel.org Cc: linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, Muhammad Bilal Subject: [PATCH] media: dvb_ca_en50221: bail out of write loop on non-positive fraglen Date: Sun, 20 Sep 2026 00:23:29 +0500 Message-ID: <20260919192329.272325-1-meatuni001@gmail.com> X-Mailer: git-send-email 2.55.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit dvb_ca_en50221_io_write() derives fraglen from sl->link_buf_size, a value negotiated with the CAM in dvb_ca_en50221_link_init() and only ever clamped on the high end against HOST_LINK_BUF_SIZE. The loop guards against a negative fraglen (link_buf_size < 2) but not against fraglen == 0 (link_buf_size == 2 exactly): "fragpos += fraglen" at the bottom of the loop then adds zero, so fragpos never reaches count and the write() never returns while a positive count remains to be sent. Treat a non-positive fraglen the same as a negative one and stop fragmenting, consistent with how the existing check already handles link_buf_size < 2. Signed-off-by: Muhammad Bilal --- drivers/media/dvb-core/dvb_ca_en50221.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/media/dvb-core/dvb_ca_en50221.c b/drivers/media/dvb-core/dvb_ca_en50221.c index 1b91ebb8f667..9131f62c1258 100644 --- a/drivers/media/dvb-core/dvb_ca_en50221.c +++ b/drivers/media/dvb-core/dvb_ca_en50221.c @@ -1487,7 +1487,7 @@ static ssize_t dvb_ca_en50221_io_write(struct file *file, /* fragment the packets & store in the buffer */ while (fragpos < count) { fraglen = sl->link_buf_size - 2; - if (fraglen < 0) + if (fraglen <= 0) break; if (fraglen > HOST_LINK_BUF_SIZE - 2) fraglen = HOST_LINK_BUF_SIZE - 2; -- 2.55.0