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From: "Albert Cahalan" <acahalan@gmail.com>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: "Serge E. Hallyn" <serge@hallyn.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	pbadari@us.ibm.com, torvalds@linux-foundation.org
Subject: Re: [RFC][PATCH] /proc/pid/maps doesn't match "ipcs -m" shmid
Date: Fri, 8 Jun 2007 00:41:45 -0400	[thread overview]
Message-ID: <787b0d920706072141s5a34ecb3n97007ad857ba4dc9@mail.gmail.com> (raw)
In-Reply-To: <m1ir9zrtwe.fsf@ebiederm.dsl.xmission.com>

On 6/7/07, Eric W. Biederman <ebiederm@xmission.com> wrote:

> So it looks to me like we need to do three things:
> - Fix the inode number
> - Fix the name on the hugetlbfs dentry to hold the key
> - Add a big fat comment that user space programs depend on this
>   behavior of both the dentry name and the inode number.

Assuming that this proposed fix goes in:

Since the inode number is the shmid, and this is a number
that the kernel randomly chooses AFAIK, there should be
no need to have different shm segments sharing the same
inode number.

The situation with the key is a bit more disturbing, though
we already hit that anyway when IPC_PRIVATE is used.
(why anybody would NOT use IPC_PRIVATE is a mystery)
So having the key in the name doesn't make things worse.

I have some concern about the device minor number.
This should be the same for all shm mappings; I do not
know if the behavior changed.

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  reply	other threads:[~2007-06-08  4:41 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-06-07  3:27 Albert Cahalan
2007-06-07  3:44 ` Andrew Morton
2007-06-07  4:53   ` Albert Cahalan
2007-06-07 16:20     ` Serge E. Hallyn
2007-06-08  3:45       ` Eric W. Biederman
2007-06-08  4:41         ` Albert Cahalan [this message]
2007-06-08  5:55           ` Eric W. Biederman
2007-06-08  6:51             ` Albert Cahalan
2007-06-08 22:31               ` [PATCH] Restore shmid as inode# to fix /proc/pid/maps ABI breakage Badari Pulavarty
2007-06-08 16:07         ` [RFC][PATCH] /proc/pid/maps doesn't match "ipcs -m" shmid Badari Pulavarty
2007-06-08 23:43           ` [PATCH] shm: Fix the filename of hugetlb sysv shared memory Eric W. Biederman
2007-06-08 23:55             ` Andrew Morton
2007-06-09  4:32               ` Badari Pulavarty
2007-06-09  8:01                 ` Eric W. Biederman
2007-06-11 18:11             ` Andrew Morton
2007-06-11 19:55               ` Badari Pulavarty
2007-06-11 19:00             ` Adam Litke
2007-06-11 20:53               ` Ken Chen
2007-06-07 16:23     ` [RFC][PATCH] /proc/pid/maps doesn't match "ipcs -m" shmid Badari Pulavarty
2007-06-07 16:43       ` Albert Cahalan
2007-06-07 17:06         ` Badari Pulavarty
2007-06-07 19:48           ` Andrew Morton
2007-06-07 19:59             ` Badari Pulavarty
2007-06-07 20:37               ` Serge E. Hallyn
2007-06-07 20:51                 ` Serge E. Hallyn
2007-06-07 21:16                 ` Badari Pulavarty
2007-06-07 22:08                   ` Serge E. Hallyn
2007-06-07 22:21                     ` Badari Pulavarty
2007-06-07 22:22                     ` Serge E. Hallyn
2007-06-07 23:57                       ` Badari Pulavarty
  -- strict thread matches above, loose matches on Subject: below --
2007-06-06 16:07 Badari Pulavarty
2007-06-06 17:02 ` Eric W. Biederman
2007-06-06 17:37   ` Badari Pulavarty
2007-06-06 18:24     ` Eric W. Biederman

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