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Wyatt IV" , John Kacur , Shuah Khan Cc: linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, Shuah Khan References: <20260903082644.5149-1-liujing@cmss.chinamobile.com> Content-Language: en-US From: Shuah Khan In-Reply-To: <20260903082644.5149-1-liujing@cmss.chinamobile.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 9/3/26 02:26, liujing wrote: > From: Liu Jing > > In amd_fam14h_get_nb_power(), the expression `1 << 31` performs a > signed integer shift, which is undefined behavior in C. > > Fix it by using `1U << 31` to perform an unsigned shift. How did you find this problem? > > Signed-off-by: Liu Jing > --- > --- a/tools/power/cpupower/utils/idle_monitor/amd_fam14h_idle.c > +++ b/tools/power/cpupower/utils/idle_monitor/amd_fam14h_idle.c > @@ -270,7 +270,7 @@ > { > uint32_t val; > val = pci_read_long(amd_fam14h_pci_dev, PCI_NBP1_CAP_OFFSET); > - return val & (1 << 31); > + return val & (1U << 31); > } > > struct cpuidle_monitor *amd_fam14h_register(void) > > > > thanks, -- Shuah