From: ebiederm@xmission.com (Eric W. Biederman)
To: Nagarathnam Muthusamy <nagarathnam.muthusamy@oracle.com>
Cc: kernel test robot <fengguang.wu@intel.com>, LKP <lkp@01.org>,
linux-kernel@vger.kernel.org, wfg@linux.intel.com
Subject: Re: 98f929b1bd ("ipc/shm: Fix shmctl(..., IPC_STAT, ...) between .."): Oops: 0000 [#1]
Date: Wed, 28 Mar 2018 12:53:31 -0500 [thread overview]
Message-ID: <87o9j8axyc.fsf@xmission.com> (raw)
In-Reply-To: <f249d351-240a-8c0e-ef50-f9155b696e86@oracle.com> (Nagarathnam Muthusamy's message of "Wed, 28 Mar 2018 10:22:16 -0700")
Nagarathnam Muthusamy <nagarathnam.muthusamy@oracle.com> writes:
> Hi Eric,
>
> From
> https://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace.git/tree/ipc/shm.c?h=for-next
>
> It looks like if the following condition in Line 616 succeeds
>
> error = PTR_ERR(file);
> if (IS_ERR(file))
> goto no_file;
>
> we get to no_file with garbage value in shm_cprid. An attempt to
> put_pid on this garbage value might be causing panic.
>
> We could initialize shm_cprid to NULL as soon as it was created.
Yes. I misread the kvmalloc as a kvzalloc.
I am planning on placing the pid freeing under the no_id label
instead of the no_file label. Which should also avoid the issue.
It is a rare enough issue an incremental patch should be fine.
Eric
WARNING: multiple messages have this Message-ID (diff)
From: Eric W. Biederman <ebiederm@xmission.com>
To: lkp@lists.01.org
Subject: Re: 98f929b1bd ("ipc/shm: Fix shmctl(..., IPC_STAT, ...) between .."): Oops: 0000 [#1]
Date: Wed, 28 Mar 2018 12:53:31 -0500 [thread overview]
Message-ID: <87o9j8axyc.fsf@xmission.com> (raw)
In-Reply-To: <f249d351-240a-8c0e-ef50-f9155b696e86@oracle.com>
[-- Attachment #1: Type: text/plain, Size: 796 bytes --]
Nagarathnam Muthusamy <nagarathnam.muthusamy@oracle.com> writes:
> Hi Eric,
>
> From
> https://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace.git/tree/ipc/shm.c?h=for-next
>
> It looks like if the following condition in Line 616 succeeds
>
> error = PTR_ERR(file);
> if (IS_ERR(file))
> goto no_file;
>
> we get to no_file with garbage value in shm_cprid. An attempt to
> put_pid on this garbage value might be causing panic.
>
> We could initialize shm_cprid to NULL as soon as it was created.
Yes. I misread the kvmalloc as a kvzalloc.
I am planning on placing the pid freeing under the no_id label
instead of the no_file label. Which should also avoid the issue.
It is a rare enough issue an incremental patch should be fine.
Eric
next prev parent reply other threads:[~2018-03-28 17:54 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-28 7:29 98f929b1bd ("ipc/shm: Fix shmctl(..., IPC_STAT, ...) between .."): Oops: 0000 [#1] kernel test robot
2018-03-28 7:29 ` kernel test robot
2018-03-28 17:22 ` Nagarathnam Muthusamy
2018-03-28 17:22 ` Nagarathnam Muthusamy
2018-03-28 17:53 ` Eric W. Biederman [this message]
2018-03-28 17:53 ` Eric W. Biederman
2018-03-28 18:47 ` [PATCH] ipc/shm: Fix pid freeing Eric W. Biederman
2018-03-28 18:47 ` Eric W. Biederman
2018-03-28 19:57 ` Nagarathnam Muthusamy
2018-03-28 19:57 ` Nagarathnam Muthusamy
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=87o9j8axyc.fsf@xmission.com \
--to=ebiederm@xmission.com \
--cc=fengguang.wu@intel.com \
--cc=linux-kernel@vger.kernel.org \
--cc=lkp@01.org \
--cc=nagarathnam.muthusamy@oracle.com \
--cc=wfg@linux.intel.com \
/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.