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[68.147.8.254]) by smtp.gmail.com with ESMTPSA id vg8sm1975886igb.15.2016.04.22.10.14.33 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Fri, 22 Apr 2016 10:14:34 -0700 (PDT) From: Mathieu Poirier To: linux-arm-kernel@lists.infradead.org, Suzuki.Poulose@arm.com Subject: [PATCH V3 10/18] coresight: tmc: getting the right read_count on tmc_open() Date: Fri, 22 Apr 2016 11:14:07 -0600 Message-Id: <1461345255-11758-11-git-send-email-mathieu.poirier@linaro.org> X-Mailer: git-send-email 2.5.0 In-Reply-To: <1461345255-11758-1-git-send-email-mathieu.poirier@linaro.org> References: <1461345255-11758-1-git-send-email-mathieu.poirier@linaro.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20160422_101457_124166_76AF3809 X-CRM114-Status: GOOD ( 11.15 ) X-Spam-Score: -2.7 (--) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-kernel@vger.kernel.org MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-5.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_MED,RP_MATCHES_RCVD,T_DKIM_INVALID,UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP In function tmc_open(), if tmc_read_prepare() fails variable drvdata->read_count is not decremented, causing unwanted access to drvdata->buf and very likely, a crash dump. By moving the incrementation to a place where we know things are stable this kind of situation is avoided. Signed-off-by: Mathieu Poirier Reviewed-by: Suzuki K Poulose --- drivers/hwtracing/coresight/coresight-tmc.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/hwtracing/coresight/coresight-tmc.c b/drivers/hwtracing/coresight/coresight-tmc.c index e8e12a9b917a..55806352b1f1 100644 --- a/drivers/hwtracing/coresight/coresight-tmc.c +++ b/drivers/hwtracing/coresight/coresight-tmc.c @@ -121,13 +121,14 @@ static int tmc_open(struct inode *inode, struct file *file) struct tmc_drvdata, miscdev); int ret = 0; - if (drvdata->read_count++) + if (drvdata->read_count) goto out; ret = tmc_read_prepare(drvdata); if (ret) return ret; out: + drvdata->read_count++; nonseekable_open(inode, file); dev_dbg(drvdata->dev, "%s: successfully opened\n", __func__);