* [PATCH v2] userfaultfd: fix UFFDIO_CONTINUE ioctl request definition
@ 2021-06-01 14:34 Gleb Fotengauer-Malinovskiy
2021-06-01 16:41 ` Axel Rasmussen
2021-06-23 2:42 ` Dmitry V. Levin
0 siblings, 2 replies; 3+ messages in thread
From: Gleb Fotengauer-Malinovskiy @ 2021-06-01 14:34 UTC (permalink / raw)
To: Andrew Morton, Axel Rasmussen, Peter Xu, Mike Kravetz,
Andrea Arcangeli, Lokesh Gidra, linux-kernel
Cc: Gleb Fotengauer-Malinovskiy
This ioctl request reads from uffdio_continue structure which justifies
_IOC_READ flag.
See NOTEs in include/uapi/asm-generic/ioctl.h for more information.
Fixes: f619147104c8 ("userfaultfd: add UFFDIO_CONTINUE ioctl")
Signed-off-by: Gleb Fotengauer-Malinovskiy <glebfm@altlinux.org>
Acked-by: Peter Xu <peterx@redhat.com>
---
include/uapi/linux/userfaultfd.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
v2 fix commit message
diff --git a/include/uapi/linux/userfaultfd.h b/include/uapi/linux/userfaultfd.h
index bafbeb1a2624..650480f41f1d 100644
--- a/include/uapi/linux/userfaultfd.h
+++ b/include/uapi/linux/userfaultfd.h
@@ -80,8 +80,8 @@
struct uffdio_zeropage)
#define UFFDIO_WRITEPROTECT _IOWR(UFFDIO, _UFFDIO_WRITEPROTECT, \
struct uffdio_writeprotect)
-#define UFFDIO_CONTINUE _IOR(UFFDIO, _UFFDIO_CONTINUE, \
- struct uffdio_continue)
+#define UFFDIO_CONTINUE _IOWR(UFFDIO, _UFFDIO_CONTINUE, \
+ struct uffdio_continue)
/* read() structure */
struct uffd_msg {
--
glebfm
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH v2] userfaultfd: fix UFFDIO_CONTINUE ioctl request definition
2021-06-01 14:34 [PATCH v2] userfaultfd: fix UFFDIO_CONTINUE ioctl request definition Gleb Fotengauer-Malinovskiy
@ 2021-06-01 16:41 ` Axel Rasmussen
2021-06-23 2:42 ` Dmitry V. Levin
1 sibling, 0 replies; 3+ messages in thread
From: Axel Rasmussen @ 2021-06-01 16:41 UTC (permalink / raw)
To: Gleb Fotengauer-Malinovskiy
Cc: Andrew Morton, Peter Xu, Mike Kravetz, Andrea Arcangeli,
Lokesh Gidra, LKML
Thanks for catching this!
Reviewed-by: Axel Rasmussen <axelrasmussen@google.com>
On Tue, Jun 1, 2021 at 7:34 AM Gleb Fotengauer-Malinovskiy
<glebfm@altlinux.org> wrote:
>
> This ioctl request reads from uffdio_continue structure which justifies
> _IOC_READ flag.
> See NOTEs in include/uapi/asm-generic/ioctl.h for more information.
>
> Fixes: f619147104c8 ("userfaultfd: add UFFDIO_CONTINUE ioctl")
> Signed-off-by: Gleb Fotengauer-Malinovskiy <glebfm@altlinux.org>
> Acked-by: Peter Xu <peterx@redhat.com>
> ---
> include/uapi/linux/userfaultfd.h | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> v2 fix commit message
>
> diff --git a/include/uapi/linux/userfaultfd.h b/include/uapi/linux/userfaultfd.h
> index bafbeb1a2624..650480f41f1d 100644
> --- a/include/uapi/linux/userfaultfd.h
> +++ b/include/uapi/linux/userfaultfd.h
> @@ -80,8 +80,8 @@
> struct uffdio_zeropage)
> #define UFFDIO_WRITEPROTECT _IOWR(UFFDIO, _UFFDIO_WRITEPROTECT, \
> struct uffdio_writeprotect)
> -#define UFFDIO_CONTINUE _IOR(UFFDIO, _UFFDIO_CONTINUE, \
> - struct uffdio_continue)
> +#define UFFDIO_CONTINUE _IOWR(UFFDIO, _UFFDIO_CONTINUE, \
> + struct uffdio_continue)
>
> /* read() structure */
> struct uffd_msg {
> --
> glebfm
>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH v2] userfaultfd: fix UFFDIO_CONTINUE ioctl request definition
2021-06-01 14:34 [PATCH v2] userfaultfd: fix UFFDIO_CONTINUE ioctl request definition Gleb Fotengauer-Malinovskiy
2021-06-01 16:41 ` Axel Rasmussen
@ 2021-06-23 2:42 ` Dmitry V. Levin
1 sibling, 0 replies; 3+ messages in thread
From: Dmitry V. Levin @ 2021-06-23 2:42 UTC (permalink / raw)
To: Andrew Morton
Cc: Gleb Fotengauer-Malinovskiy, Axel Rasmussen, Peter Xu,
Mike Kravetz, Andrea Arcangeli, Lokesh Gidra, linux-kernel
Hi,
On Tue, Jun 01, 2021 at 05:34:32PM +0300, Gleb Fotengauer-Malinovskiy wrote:
> This ioctl request reads from uffdio_continue structure which justifies
> _IOC_READ flag.
> See NOTEs in include/uapi/asm-generic/ioctl.h for more information.
These ioctl flag usage rules seem to be a perpetual source of mistakes.
I suggest a slightly different wording of the commit message which is
hopefully a bit easier to follow:
"This ioctl request reads from uffdio_continue structure written by
userspace which justifies _IOC_WRITE flag. It also writes back to that
structure which justifies _IOC_READ flag.
See NOTEs in include/uapi/asm-generic/ioctl.h for more information."
Please make sure this patch is merged before v5.13 is released, otherwise
the UAPI bug would have to stay for backwards ABI compatibility.
> Fixes: f619147104c8 ("userfaultfd: add UFFDIO_CONTINUE ioctl")
> Signed-off-by: Gleb Fotengauer-Malinovskiy <glebfm@altlinux.org>
> Acked-by: Peter Xu <peterx@redhat.com>
> ---
> include/uapi/linux/userfaultfd.h | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> v2 fix commit message
>
> diff --git a/include/uapi/linux/userfaultfd.h b/include/uapi/linux/userfaultfd.h
> index bafbeb1a2624..650480f41f1d 100644
> --- a/include/uapi/linux/userfaultfd.h
> +++ b/include/uapi/linux/userfaultfd.h
> @@ -80,8 +80,8 @@
> struct uffdio_zeropage)
> #define UFFDIO_WRITEPROTECT _IOWR(UFFDIO, _UFFDIO_WRITEPROTECT, \
> struct uffdio_writeprotect)
> -#define UFFDIO_CONTINUE _IOR(UFFDIO, _UFFDIO_CONTINUE, \
> - struct uffdio_continue)
> +#define UFFDIO_CONTINUE _IOWR(UFFDIO, _UFFDIO_CONTINUE, \
> + struct uffdio_continue)
>
> /* read() structure */
> struct uffd_msg {
Reviewed-by: Dmitry V. Levin <ldv@altlinux.org>
--
ldv
^ permalink raw reply [flat|nested] 3+ messages in thread
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2021-06-01 14:34 [PATCH v2] userfaultfd: fix UFFDIO_CONTINUE ioctl request definition Gleb Fotengauer-Malinovskiy
2021-06-01 16:41 ` Axel Rasmussen
2021-06-23 2:42 ` Dmitry V. Levin
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