From mboxrd@z Thu Jan 1 00:00:00 1970 From: sergei.shtylyov@cogentembedded.com (Sergei Shtylyov) Date: Mon, 08 Sep 2014 19:43:44 +0400 Subject: [PATCHv2] rtc: pcf8563: fix uninitialized use warning In-Reply-To: <2750370.rlMuFcoBUA@wuerfel> References: <2750370.rlMuFcoBUA@wuerfel> Message-ID: <540DCEB0.6030108@cogentembedded.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 9/8/2014 7:26 PM, Arnd Bergmann wrote: > gcc-4.9 found a potential condition under which the 'pending' > variable may be used uninitialized: > drivers/rtc/rtc-pcf8563.c: In function 'pcf8563_irq': > drivers/rtc/rtc-pcf8563.c:173:5: warning: 'pending' may be used uninitialized in this function [-Wmaybe-uninitialized] > This is because in the pcf8563_get_alarm_mode() function, we > check any nonzero return of pcf8563_read_block_data, but > in the irq function we only check for negative values, so > a possible positive value does not get detected if the compiler > chooses not to inline the entire call chain. > Checking for any non-zero value in the interrupt handler as well > is just as correct and lets the compiler know what we are doing, > without needing a bogus initialization. > As pointed out by Sergei Shtylyov, the same code section contains > another bug: an interrupt handler is not supposed to return > an errno value. Let's fix this as well by returning IRQ_NONE > in case of a communication error. > Signed-off-by: Arnd Bergmann If you're fixing both issues in one patch, it probably needs somewhat modified subject, like "rtc: pcf8356: fix error handling". WBR, Sergei