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

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Message-ID: <20260203200505.GH3183987@ZenIV>
Date: Tue, 3 Feb 2026 20:05:05 +0000
From: Al Viro <viro@...iv.linux.org.uk>
To: Waiman Long <longman@...hat.com>
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 Tue, Feb 03, 2026 at 02:44:33PM -0500, Waiman Long wrote:

> diff --git a/kernel/audit.h b/kernel/audit.h
> index 7c401729e21b..03f3539b10e7 100644
> --- a/kernel/audit.h
> +++ b/kernel/audit.h
> @@ -133,6 +133,13 @@ struct audit_context {
>  	int		    name_count; /* total records in names_list */
>  	struct list_head    names_list;	/* struct audit_names->list anchor */
>  	char		    *filterkey;	/* key for rule that triggered record */
> +	/*
> +	 * pwd_reset is set if audit_free_names() has been called from
> +	 * audit_reset_context() to reset pwd, but pwd is still holding dentry
> +	 * and mount references to be used in later audit action without
> +	 * the need to reacqure the references again.

That's a delicate way to say "we have mounts stuck busy inexplicably for userland"...

Generally a chdir(2) away from something immediately followed by umount(2)
is _not_ expected to leave you with -EBUSY when nobody else has been doing
anything with the mount in question.