From: Jonathan Corbet <corbet@lwn.net>
To: Dave Hansen <dave@sr71.net>
Cc: linux-kernel@vger.kernel.org, x86@kernel.org,
linux-api@vger.kernel.org, linux-arch@vger.kernel.org,
linux-mm@kvack.org, torvalds@linux-foundation.org,
akpm@linux-foundation.org, dave.hansen@linux.intel.com
Subject: Re: [PATCH 5/8] x86, pkeys: allocation/free syscalls
Date: Wed, 1 Jun 2016 12:37:05 -0600 [thread overview]
Message-ID: <20160601123705.72a606e7@lwn.net> (raw)
In-Reply-To: <20160531152822.FE8D405E@viggo.jf.intel.com>
Sorry, I have one more obnoxious question...
> +static inline
> +int mm_pkey_free(struct mm_struct *mm, int pkey)
> +{
> + /*
> + * pkey 0 is special, always allocated and can never
> + * be freed.
> + */
> + if (!pkey || !validate_pkey(pkey))
> + return -EINVAL;
> + if (!mm_pkey_is_allocated(mm, pkey))
> + return -EINVAL;
> +
> + mm_set_pkey_free(mm, pkey);
> +
> + return 0;
> +}
If I read this right, it doesn't actually remove any pkey restrictions
that may have been applied while the key was allocated. So there could be
pages with that key assigned that might do surprising things if the key is
reallocated for another use later, right? Is that how the API is intended
to work?
Thanks,
jon
next prev parent reply other threads:[~2016-06-01 18:37 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-31 15:28 [PATCH 0/8] System Calls for Memory Protection Keys Dave Hansen
2016-05-31 15:28 ` [PATCH 1/8] x86, pkeys: add fault handling for PF_PK page fault bit Dave Hansen
2016-05-31 15:28 ` [PATCH 2/8] mm: implement new pkey_mprotect() system call Dave Hansen
2016-05-31 15:28 ` [PATCH 3/8] x86, pkeys: make mprotect_key() mask off additional vm_flags Dave Hansen
2016-05-31 15:28 ` [PATCH 4/8] x86: wire up mprotect_key() system call Dave Hansen
2016-05-31 15:28 ` [PATCH 5/8] x86, pkeys: allocation/free syscalls Dave Hansen
2016-06-01 18:37 ` Jonathan Corbet [this message]
2016-06-01 19:32 ` Dave Hansen
2016-06-02 0:11 ` Michael Kerrisk (man-pages)
2016-06-02 0:17 ` Dave Hansen
2016-06-03 0:26 ` Michael Kerrisk (man-pages)
2016-06-03 17:28 ` Dave Hansen
2016-06-03 19:27 ` Michael Kerrisk (man-pages)
2016-06-01 20:48 ` Arnd Bergmann
2016-06-02 21:10 ` Dave Hansen
2016-05-31 15:28 ` [PATCH 6/8] x86, pkeys: add pkey set/get syscalls Dave Hansen
2016-05-31 15:28 ` [PATCH 7/8] pkeys: add details of system call use to Documentation/ Dave Hansen
2016-06-01 16:43 ` Jonathan Corbet
2016-06-01 16:46 ` Dave Hansen
2016-06-01 16:49 ` Jonathan Corbet
2016-06-01 17:10 ` Dave Hansen
2016-05-31 15:28 ` [PATCH 8/8] x86, pkeys: add self-tests Dave Hansen
-- strict thread matches above, loose matches on Subject: below --
2016-04-11 15:54 [PATCH 0/8] System Calls for Memory Protection Keys Dave Hansen
2016-04-11 15:54 ` [PATCH 5/8] x86, pkeys: allocation/free syscalls Dave Hansen
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=20160601123705.72a606e7@lwn.net \
--to=corbet@lwn.net \
--cc=akpm@linux-foundation.org \
--cc=dave.hansen@linux.intel.com \
--cc=dave@sr71.net \
--cc=linux-api@vger.kernel.org \
--cc=linux-arch@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=torvalds@linux-foundation.org \
--cc=x86@kernel.org \
/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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).