All of lore.kernel.org
 help / color / mirror / Atom feed
From: Ingo Molnar <mingo@kernel.org>
To: Arnd Bergmann <arnd@arndb.de>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	Michal Hocko <mhocko@suse.com>,
	"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
	Lorenzo Stoakes <lstoakes@gmail.com>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mm: gup: fix access_ok() argument type
Date: Sun, 23 Apr 2017 11:20:21 +0200	[thread overview]
Message-ID: <20170423092021.xpfyapinlxmxpi5l@gmail.com> (raw)
In-Reply-To: <20170421162659.3314521-1-arnd@arndb.de>


* Arnd Bergmann <arnd@arndb.de> wrote:

> MIPS just got changed to only accept a pointer argument for access_ok(),
> causing one warning in drivers/scsi/pmcraid.c. I tried changing x86
> the same way and found the same warning in __get_user_pages_fast()
> and nowhere else in the kernel during randconfig testing:

Doing that for x86 access_ok() would definitely be a good idea.

> mm/gup.c: In function '__get_user_pages_fast':
> mm/gup.c:1578:6: error: passing argument 1 of '__chk_range_not_ok' makes pointer from integer without a cast [-Werror=int-conversion]
> 
> It would probably be a good idea to enforce type-safety in general,
> so let's change this file to not cause a warning if we do that.
> 
> I don't know why the warning did not appear on MIPS.
> 
> Fixes: 2667f50e8b81 ("mm: introduce a general RCU get_user_pages_fast()")
> Cc: Alexander Viro <viro@zeniv.linux.org.uk>
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
>  mm/gup.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/mm/gup.c b/mm/gup.c
> index 2559a3987de7..7f5bc26d9229 100644
> --- a/mm/gup.c
> +++ b/mm/gup.c
> @@ -1575,7 +1575,7 @@ int __get_user_pages_fast(unsigned long start, int nr_pages, int write,
>  	end = start + len;
>  
>  	if (unlikely(!access_ok(write ? VERIFY_WRITE : VERIFY_READ,
> -					start, len)))
> +					(void __user *)start, len)))
>  		return 0;

Acked-by: Ingo Molnar <mingo@kernel.org>

Thanks,

	Ingo

WARNING: multiple messages have this Message-ID (diff)
From: Ingo Molnar <mingo@kernel.org>
To: Arnd Bergmann <arnd@arndb.de>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	Michal Hocko <mhocko@suse.com>,
	"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
	Lorenzo Stoakes <lstoakes@gmail.com>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mm: gup: fix access_ok() argument type
Date: Sun, 23 Apr 2017 11:20:21 +0200	[thread overview]
Message-ID: <20170423092021.xpfyapinlxmxpi5l@gmail.com> (raw)
In-Reply-To: <20170421162659.3314521-1-arnd@arndb.de>


* Arnd Bergmann <arnd@arndb.de> wrote:

> MIPS just got changed to only accept a pointer argument for access_ok(),
> causing one warning in drivers/scsi/pmcraid.c. I tried changing x86
> the same way and found the same warning in __get_user_pages_fast()
> and nowhere else in the kernel during randconfig testing:

Doing that for x86 access_ok() would definitely be a good idea.

> mm/gup.c: In function '__get_user_pages_fast':
> mm/gup.c:1578:6: error: passing argument 1 of '__chk_range_not_ok' makes pointer from integer without a cast [-Werror=int-conversion]
> 
> It would probably be a good idea to enforce type-safety in general,
> so let's change this file to not cause a warning if we do that.
> 
> I don't know why the warning did not appear on MIPS.
> 
> Fixes: 2667f50e8b81 ("mm: introduce a general RCU get_user_pages_fast()")
> Cc: Alexander Viro <viro@zeniv.linux.org.uk>
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
>  mm/gup.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/mm/gup.c b/mm/gup.c
> index 2559a3987de7..7f5bc26d9229 100644
> --- a/mm/gup.c
> +++ b/mm/gup.c
> @@ -1575,7 +1575,7 @@ int __get_user_pages_fast(unsigned long start, int nr_pages, int write,
>  	end = start + len;
>  
>  	if (unlikely(!access_ok(write ? VERIFY_WRITE : VERIFY_READ,
> -					start, len)))
> +					(void __user *)start, len)))
>  		return 0;

Acked-by: Ingo Molnar <mingo@kernel.org>

Thanks,

	Ingo

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

  reply	other threads:[~2017-04-23  9:20 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-04-21 16:26 [PATCH] mm: gup: fix access_ok() argument type Arnd Bergmann
2017-04-21 16:26 ` Arnd Bergmann
2017-04-23  9:20 ` Ingo Molnar [this message]
2017-04-23  9:20   ` Ingo Molnar

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20170423092021.xpfyapinlxmxpi5l@gmail.com \
    --to=mingo@kernel.org \
    --cc=akpm@linux-foundation.org \
    --cc=arnd@arndb.de \
    --cc=kirill.shutemov@linux.intel.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=lstoakes@gmail.com \
    --cc=mhocko@suse.com \
    --cc=viro@zeniv.linux.org.uk \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.