2018-06-07 16:27:32

by Geert Uytterhoeven

Subject: [PATCH] xsk: Fix umem fill/completion queue mmap on 32-bit

With gcc-4.1.2 on 32-bit:

net/xdp/xsk.c:663: warning: integer constant is too large for ‘long’ type
net/xdp/xsk.c:665: warning: integer constant is too large for ‘long’ type

Add the missing "ULL" suffixes to the large XDP_UMEM_PGOFF_*_RING values
to fix this.

net/xdp/xsk.c:663: warning: comparison is always false due to limited range of data type
net/xdp/xsk.c:665: warning: comparison is always false due to limited range of data type

"unsigned long" is 32-bit on 32-bit systems, hence the offset is
truncated, and can never be equal to any of the XDP_UMEM_PGOFF_*_RING
values. Use loff_t (and the required cast) to fix this.

Fixes: 423f38329d267969 ("xsk: add umem fill queue support and mmap")
Fixes: fe2308328cd2f26e ("xsk: add umem completion queue support and mmap")
Signed-off-by: Geert Uytterhoeven <[email protected]>
---
Compile-tested only.
---
include/uapi/linux/if_xdp.h | 4 ++--
net/xdp/xsk.c | 2 +-
2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/include/uapi/linux/if_xdp.h b/include/uapi/linux/if_xdp.h
index 1fa0e977ea8d0224..caed8b1614ffc0aa 100644
--- a/include/uapi/linux/if_xdp.h
+++ b/include/uapi/linux/if_xdp.h
@@ -63,8 +63,8 @@ struct xdp_statistics {
/* Pgoff for mmaping the rings */
#define XDP_PGOFF_RX_RING 0
#define XDP_PGOFF_TX_RING 0x80000000
-#define XDP_UMEM_PGOFF_FILL_RING 0x100000000
-#define XDP_UMEM_PGOFF_COMPLETION_RING 0x180000000
+#define XDP_UMEM_PGOFF_FILL_RING 0x100000000ULL
+#define XDP_UMEM_PGOFF_COMPLETION_RING 0x180000000ULL

/* Rx/Tx descriptor */
struct xdp_desc {
diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c
index c6ed2454f7ce55e8..36919a254ba370c3 100644
--- a/net/xdp/xsk.c
+++ b/net/xdp/xsk.c
@@ -643,7 +643,7 @@ static int xsk_getsockopt(struct socket *sock, int level, int optname,
static int xsk_mmap(struct file *file, struct socket *sock,
struct vm_area_struct *vma)
{
- unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
+ loff_t offset = (loff_t)vma->vm_pgoff << PAGE_SHIFT;
unsigned long size = vma->vm_end - vma->vm_start;
struct xdp_sock *xs = xdp_sk(sock->sk);
struct xsk_queue *q = NULL;
--
2.7.4

2018-06-07 19:01:21

by Björn Töpel

Subject: Re: [PATCH] xsk: Fix umem fill/completion queue mmap on 32-bit

Den tors 7 juni 2018 kl 15:37 skrev Geert Uytterhoeven <[email protected]>:
>
> With gcc-4.1.2 on 32-bit:
>
> net/xdp/xsk.c:663: warning: integer constant is too large for ‘long’ type
> net/xdp/xsk.c:665: warning: integer constant is too large for ‘long’ type
>
> Add the missing "ULL" suffixes to the large XDP_UMEM_PGOFF_*_RING values
> to fix this.
>
> net/xdp/xsk.c:663: warning: comparison is always false due to limited range of data type
> net/xdp/xsk.c:665: warning: comparison is always false due to limited range of data type
>
> "unsigned long" is 32-bit on 32-bit systems, hence the offset is
> truncated, and can never be equal to any of the XDP_UMEM_PGOFF_*_RING
> values. Use loff_t (and the required cast) to fix this.
>
> Fixes: 423f38329d267969 ("xsk: add umem fill queue support and mmap")
> Fixes: fe2308328cd2f26e ("xsk: add umem completion queue support and mmap")
> Signed-off-by: Geert Uytterhoeven <[email protected]>
> ---
> Compile-tested only.
> ---
> include/uapi/linux/if_xdp.h | 4 ++--
> net/xdp/xsk.c | 2 +-
> 2 files changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/include/uapi/linux/if_xdp.h b/include/uapi/linux/if_xdp.h
> index 1fa0e977ea8d0224..caed8b1614ffc0aa 100644
> --- a/include/uapi/linux/if_xdp.h
> +++ b/include/uapi/linux/if_xdp.h
> @@ -63,8 +63,8 @@ struct xdp_statistics {
> /* Pgoff for mmaping the rings */
> #define XDP_PGOFF_RX_RING 0
> #define XDP_PGOFF_TX_RING 0x80000000
> -#define XDP_UMEM_PGOFF_FILL_RING 0x100000000
> -#define XDP_UMEM_PGOFF_COMPLETION_RING 0x180000000
> +#define XDP_UMEM_PGOFF_FILL_RING 0x100000000ULL
> +#define XDP_UMEM_PGOFF_COMPLETION_RING 0x180000000ULL
>
> /* Rx/Tx descriptor */
> struct xdp_desc {
> diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c
> index c6ed2454f7ce55e8..36919a254ba370c3 100644
> --- a/net/xdp/xsk.c
> +++ b/net/xdp/xsk.c
> @@ -643,7 +643,7 @@ static int xsk_getsockopt(struct socket *sock, int level, int optname,
> static int xsk_mmap(struct file *file, struct socket *sock,
> struct vm_area_struct *vma)
> {
> - unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
> + loff_t offset = (loff_t)vma->vm_pgoff << PAGE_SHIFT;
> unsigned long size = vma->vm_end - vma->vm_start;
> struct xdp_sock *xs = xdp_sk(sock->sk);
> struct xsk_queue *q = NULL;
> --
> 2.7.4
>

Thanks Geert!

Acked-by: Björn Töpel <[email protected]>

2018-06-07 22:22:12

by Daniel Borkmann

Subject: Re: [PATCH] xsk: Fix umem fill/completion queue mmap on 32-bit

On 06/07/2018 06:34 PM, Björn Töpel wrote:
> Den tors 7 juni 2018 kl 15:37 skrev Geert Uytterhoeven <[email protected]>:
>>
>> With gcc-4.1.2 on 32-bit:
>>
>> net/xdp/xsk.c:663: warning: integer constant is too large for ‘long’ type
>> net/xdp/xsk.c:665: warning: integer constant is too large for ‘long’ type
>>
>> Add the missing "ULL" suffixes to the large XDP_UMEM_PGOFF_*_RING values
>> to fix this.
>>
>> net/xdp/xsk.c:663: warning: comparison is always false due to limited range of data type
>> net/xdp/xsk.c:665: warning: comparison is always false due to limited range of data type
>>
>> "unsigned long" is 32-bit on 32-bit systems, hence the offset is
>> truncated, and can never be equal to any of the XDP_UMEM_PGOFF_*_RING
>> values. Use loff_t (and the required cast) to fix this.
>>
>> Fixes: 423f38329d267969 ("xsk: add umem fill queue support and mmap")
>> Fixes: fe2308328cd2f26e ("xsk: add umem completion queue support and mmap")
>> Signed-off-by: Geert Uytterhoeven <[email protected]>
[...]
>
> Thanks Geert!
>
> Acked-by: Björn Töpel <[email protected]>

Applied to bpf, thanks everyone!