2019-06-27 03:26:07

by Jiunn Chang

Subject: [Linux-kernel-mentees][PATCH v2] drm/amdkfd: Fix undefined behavior in bit shift

Shifting signed 32-bit value by 31 bits is undefined. Changing most
significant bit to unsigned.

Changes included in v2:
- use subsystem specific subject lines
- CC required mailing lists

Signed-off-by: Jiunn Chang <[email protected]>
---
include/uapi/linux/kfd_ioctl.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/uapi/linux/kfd_ioctl.h b/include/uapi/linux/kfd_ioctl.h
index dc067ed0b72d..ae5669272303 100644
--- a/include/uapi/linux/kfd_ioctl.h
+++ b/include/uapi/linux/kfd_ioctl.h
@@ -339,7 +339,7 @@ struct kfd_ioctl_acquire_vm_args {
#define KFD_IOC_ALLOC_MEM_FLAGS_USERPTR (1 << 2)
#define KFD_IOC_ALLOC_MEM_FLAGS_DOORBELL (1 << 3)
/* Allocation flags: attributes/access options */
-#define KFD_IOC_ALLOC_MEM_FLAGS_WRITABLE (1 << 31)
+#define KFD_IOC_ALLOC_MEM_FLAGS_WRITABLE (1U << 31)
#define KFD_IOC_ALLOC_MEM_FLAGS_EXECUTABLE (1 << 30)
#define KFD_IOC_ALLOC_MEM_FLAGS_PUBLIC (1 << 29)
#define KFD_IOC_ALLOC_MEM_FLAGS_NO_SUBSTITUTE (1 << 28)
--
2.22.0

2019-06-27 03:35:14

by Shuah Khan

Subject: Re: [Linux-kernel-mentees][PATCH v2] drm/amdkfd: Fix undefined behavior in bit shift

On 6/26/19 9:25 PM, Jiunn Chang wrote:
> Shifting signed 32-bit value by 31 bits is undefined. Changing most
> significant bit to unsigned.
>
> Changes included in v2:
> - use subsystem specific subject lines
> - CC required mailing lists
>
> Signed-off-by: Jiunn Chang <[email protected]>
> ---

Move version change lines here.

> include/uapi/linux/kfd_ioctl.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/include/uapi/linux/kfd_ioctl.h b/include/uapi/linux/kfd_ioctl.h
> index dc067ed0b72d..ae5669272303 100644
> --- a/include/uapi/linux/kfd_ioctl.h
> +++ b/include/uapi/linux/kfd_ioctl.h
> @@ -339,7 +339,7 @@ struct kfd_ioctl_acquire_vm_args {
> #define KFD_IOC_ALLOC_MEM_FLAGS_USERPTR (1 << 2)
> #define KFD_IOC_ALLOC_MEM_FLAGS_DOORBELL (1 << 3)
> /* Allocation flags: attributes/access options */
> -#define KFD_IOC_ALLOC_MEM_FLAGS_WRITABLE (1 << 31)
> +#define KFD_IOC_ALLOC_MEM_FLAGS_WRITABLE (1U << 31)
> #define KFD_IOC_ALLOC_MEM_FLAGS_EXECUTABLE (1 << 30)
> #define KFD_IOC_ALLOC_MEM_FLAGS_PUBLIC (1 << 29)
> #define KFD_IOC_ALLOC_MEM_FLAGS_NO_SUBSTITUTE (1 << 28)
>

thanks,
-- Shuah

2019-06-27 05:06:03

by Jiunn Chang

Subject: [Linux-kernel-mentees][PATCH v3] drm/amdkfd: Fix undefined behavior in bit shift

Shifting signed 32-bit value by 31 bits is undefined. Changing most
significant bit to unsigned.

Signed-off-by: Jiunn Chang <[email protected]>
---
Changes included in v3:
- remove change log from patch description

Changes included in v2:
- use subsystem specific subject lines
- CC required mailing lists

include/uapi/linux/kfd_ioctl.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/uapi/linux/kfd_ioctl.h b/include/uapi/linux/kfd_ioctl.h
index dc067ed0b72d..ae5669272303 100644
--- a/include/uapi/linux/kfd_ioctl.h
+++ b/include/uapi/linux/kfd_ioctl.h
@@ -339,7 +339,7 @@ struct kfd_ioctl_acquire_vm_args {
#define KFD_IOC_ALLOC_MEM_FLAGS_USERPTR (1 << 2)
#define KFD_IOC_ALLOC_MEM_FLAGS_DOORBELL (1 << 3)
/* Allocation flags: attributes/access options */
-#define KFD_IOC_ALLOC_MEM_FLAGS_WRITABLE (1 << 31)
+#define KFD_IOC_ALLOC_MEM_FLAGS_WRITABLE (1U << 31)
#define KFD_IOC_ALLOC_MEM_FLAGS_EXECUTABLE (1 << 30)
#define KFD_IOC_ALLOC_MEM_FLAGS_PUBLIC (1 << 29)
#define KFD_IOC_ALLOC_MEM_FLAGS_NO_SUBSTITUTE (1 << 28)
--
2.22.0