linux-kernel - Re: [PATCH] vfs: Don't leak a path when get_empty_filp in dentry

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Message-ID: <87eh47v4vc.fsf@xmission.com>
Date:	Thu, 16 Jan 2014 16:17:27 -0800
From:	ebiederm@...ssion.com (Eric W. Biederman)
To:	Al Viro <viro@...IV.linux.org.uk>
Cc:	linux-fsdevel@...r.kernel.org,
	Andrew Morton <akpm@...ux-foundation.org>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] vfs: Don't leak a path when get_empty_filp in dentry_open

Al Viro <viro@...IV.linux.org.uk> writes:

> On Thu, Jan 16, 2014 at 03:45:38PM -0800, Eric W. Biederman wrote:
>> 
>> Normally in dentry_open the passed in path is placed on the new filp
>> removing the caller from needing to worry about it.  In the rare case
>> that we can not allocate a filp the path is not consumed.  None of the
>> callers of dentry_open call path_put in their error handling when
>> dentry_open fails so call path_put for them on error and keep everyone's
>> error handling simple.
>
> You are misreading that code.  _No_ path in dentry_open() drops that
> sucker, no matter whether we succeed or fail.  do_dentry_open() grabs
> an extra reference on success, so those fput() on other failure exits
> just balance that.

Yep you are right.  My mistake.  The weird code flow tricked me.

Eric
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