From: Michal Simek <michal.simek@amd.com>
To: Sebin Sebastian <mailmesebin00@gmail.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>,
Alexandre Belloni <alexandre.belloni@bootlin.com>,
Michal Simek <michal.simek@xilinx.com>,
<linux-rtc@vger.kernel.org>,
<linux-arm-kernel@lists.infradead.org>,
<linux-kernel@vger.kernel.org>
Subject: Re: [PATCH -next] rtc: synqmp: uninitialized variable error
Date: Wed, 3 Aug 2022 07:46:42 +0200 [thread overview]
Message-ID: <6795ab10-8e8a-977d-e767-31282fa6a312@amd.com> (raw)
In-Reply-To: <20220803013117.318611-1-mailmesebin00@gmail.com>
Hi,
On 8/3/22 03:31, Sebin Sebastian wrote:
>
> fract_tick is uninitialized and can lead to uninitialized read which can
> result in any arbitrary value from previous computations. If the code
> flow doesnt execute the `if (fract_offset > (tick_mult /
> RTC_FR_MAX_TICKS)) { ` block, fract_tick is left uninitialized.
> Initializing with zero fixes the issue.
>
> Signed-off-by: Sebin Sebastian <mailmesebin00@gmail.com>
> ---
> drivers/rtc/rtc-zynqmp.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/rtc/rtc-zynqmp.c b/drivers/rtc/rtc-zynqmp.c
> index 1dd389b891fe..c9b85c838ebe 100644
> --- a/drivers/rtc/rtc-zynqmp.c
> +++ b/drivers/rtc/rtc-zynqmp.c
> @@ -203,7 +203,7 @@ static int xlnx_rtc_set_offset(struct device *dev, long offset)
> struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev);
> unsigned long long rtc_ppb = RTC_PPB;
> unsigned int tick_mult = do_div(rtc_ppb, xrtcdev->freq);
> - unsigned char fract_tick;
> + unsigned char fract_tick = 0;
> unsigned int calibval;
> short int max_tick;
> int fract_offset;
> --
> 2.34.1
>
Alexandre already send the patch for it here.
https://lore.kernel.org/r/20220727100018.3301470-1-alexandre.belloni@bootlin.com
Thanks,
Michal
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prev parent reply other threads:[~2022-08-03 5:48 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-03 1:31 [PATCH -next] rtc: synqmp: uninitialized variable error Sebin Sebastian
2022-08-03 5:46 ` Michal Simek [this message]
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