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[2001:8b0:1d0::2]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4282b89a86dsm23976025e9.1.2024.07.31.07.36.20 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 31 Jul 2024 07:36:20 -0700 (PDT) From: Peter Maydell To: qemu-devel@nongnu.org Cc: =?utf-8?q?Philippe_Mathieu-Daud=C3=A9?= , John Snow , Stefan Weil , "Richard W.M. Jones" , Hanna Reitz , Kevin Wolf , qemu-block@nongnu.org Subject: [PATCH 3/7] hw/block/pflash_cfi01: Don't decrement pfl->counter below 0 Date: Wed, 31 Jul 2024 15:36:13 +0100 Message-Id: <20240731143617.3391947-4-peter.maydell@linaro.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20240731143617.3391947-1-peter.maydell@linaro.org> References: <20240731143617.3391947-1-peter.maydell@linaro.org> MIME-Version: 1.0 Received-SPF: pass client-ip=2a00:1450:4864:20::32a; envelope-from=peter.maydell@linaro.org; helo=mail-wm1-x32a.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org In pflash_write() Coverity points out that we can decrement the unsigned pfl->counter below zero, which makes it wrap around. In fact this is harmless, because if pfl->counter is 0 at this point we also increment pfl->wcycle to 3, and the wcycle == 3 handling doesn't look at counter; the only way back into code which looks at the counter value is via wcycle == 1, which will reinitialize the counter. But it's arguably a little clearer to break early in the "counter == 0" if(), to avoid the decrement-below-zero. Resolves: Coverity CID 1547611 Signed-off-by: Peter Maydell Reviewed-by: Kevin Wolf Reviewed-by: Philippe Mathieu-Daudé --- hw/block/pflash_cfi01.c | 1 + 1 file changed, 1 insertion(+) diff --git a/hw/block/pflash_cfi01.c b/hw/block/pflash_cfi01.c index c8f1cf5a872..2f3d1dd509c 100644 --- a/hw/block/pflash_cfi01.c +++ b/hw/block/pflash_cfi01.c @@ -614,6 +614,7 @@ static void pflash_write(PFlashCFI01 *pfl, hwaddr offset, if (!pfl->counter) { trace_pflash_write(pfl->name, "block write finished"); pfl->wcycle++; + break; } pfl->counter--;