linux-kernel - Re: [PATCH v2] audit: Avoid excessive dput/dget in audit

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Message-ID: <7d9f73c4-0071-4df5-9bc4-0f58ce427a8d@redhat.com>
Date: Tue, 3 Feb 2026 15:18:40 -0500
From: Waiman Long <llong@...hat.com>
To: Al Viro <viro@...iv.linux.org.uk>
Cc: Paul Moore <paul@...l-moore.com>, Eric Paris <eparis@...hat.com>,
 Christian Brauner <brauner@...nel.org>, linux-kernel@...r.kernel.org,
 audit@...r.kernel.org, Richard Guy Briggs <rgb@...hat.com>,
 Ricardo Robaina <rrobaina@...hat.com>
Subject: Re: [PATCH v2] audit: Avoid excessive dput/dget in audit_context
 setup and reset paths


On 2/3/26 2:59 PM, Al Viro wrote:
> On Tue, Feb 03, 2026 at 02:44:33PM -0500, Waiman Long wrote:
>
>> +		/*
>> +		 * Defer the path_put() call of the old pwd to workqueue as
>> +		 * we may be in an atomic context that cannot call path_put()
>> +		 * directly because of might_sleep().
>> +		 */
>> +		pp = kmalloc(sizeof(*pp), GFP_NOFS);
> If that really gets called in atomic context, this kmalloc will
> in itself be enough to fuck you over, won't it?

Looking at the bug report again, I realized that the problem is because 
of the get_cond_fs_pwd() helper in my v1 patch call path_put() in a 
spinlock critical section. So we don't need to use workqueue here, just 
doing a path_put() should be good enough.

Thanks, Longman