public inbox for linux-kernel@vger.kernel.org
 help / color / mirror / Atom feed
From: Al Viro <viro@zeniv.linux.org.uk>
To: Waiman Long <llong@redhat.com>
Cc: Paul Moore <paul@paul-moore.com>, Eric Paris <eparis@redhat.com>,
	Christian Brauner <brauner@kernel.org>,
	linux-kernel@vger.kernel.org, audit@vger.kernel.org,
	Richard Guy Briggs <rgb@redhat.com>,
	Ricardo Robaina <rrobaina@redhat.com>
Subject: Re: [PATCH v2] audit: Avoid excessive dput/dget in audit_context setup and reset paths
Date: Thu, 5 Feb 2026 23:53:51 +0000	[thread overview]
Message-ID: <20260205235351.GU3183987@ZenIV> (raw)
In-Reply-To: <50054d23-0a89-41ec-b28b-b1ed77d93b00@redhat.com>

On Wed, Feb 04, 2026 at 11:45:17PM -0500, Waiman Long wrote:

> @@ -70,6 +74,8 @@ void chroot_fs_refs(const struct path *old_root, const
> struct>
>                                 count++;
>                                 path_get(new_root);
>                         }
> +                       count += fs->pwd_xrefs;
> +                       fs->pwd_xrefs = 0;
>                         write_sequnlock(&fs->seq);

Nope - you only need that for threads that have ->pwd equal to old_root.
Incidentally, I'd forgotten about that sucker - it kills the idea of
fdget-like tricks dead, more's the pity.  Third-party modification of
task->fs->pwd (under task->lock and task->fs->seq), possible even with
task->fs->users == 1.

FWIW, I'm going through the fs_struct uses at the moment; will post
whatever I get when I go down (or earlier, in the unlikely case it doesn't
spill to tomorrow morning), will keep posting incremental followups
until the documentation is done.  I'm sick and tired of half-finished
docs - let's see if I can push through that one this way ;-/

  reply	other threads:[~2026-02-05 23:51 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-02-03 19:44 [PATCH v2] audit: Avoid excessive dput/dget in audit_context setup and reset paths Waiman Long
2026-02-03 19:59 ` Al Viro
2026-02-03 20:18   ` Waiman Long
2026-02-03 20:05 ` Al Viro
2026-02-03 20:32   ` Waiman Long
2026-02-03 21:50     ` Al Viro
2026-02-03 23:26       ` Al Viro
2026-02-04  4:21         ` Waiman Long
2026-02-04  6:26           ` Al Viro
2026-02-04 18:16             ` Waiman Long
2026-02-04 20:18               ` Al Viro
2026-02-05  3:03                 ` Waiman Long
2026-02-05  4:45                   ` Waiman Long
2026-02-05 23:53                     ` Al Viro [this message]
2026-02-06  1:20                       ` Waiman Long
2026-02-06  4:11                         ` Waiman Long
2026-02-06  4:19                           ` Waiman Long
2026-02-06  5:22                           ` Al Viro
2026-02-06  6:31                             ` Al Viro
2026-02-06  6:38                               ` Al Viro
2026-02-06  7:13                             ` Al Viro
2026-02-06 19:16                             ` Waiman Long
2026-02-06 20:04                               ` Waiman Long
2026-02-06 20:38                                 ` Al Viro
2026-02-07  8:25                                 ` [PATCH][RFC] bug in unshare(2) failure recovery Al Viro
2026-02-07 23:06                                   ` Waiman Long
2026-02-17 12:49                                   ` Christian Brauner
2026-02-17 12:49                                   ` Christian Brauner
2026-02-06 20:29                               ` [PATCH v2] audit: Avoid excessive dput/dget in audit_context setup and reset paths Al Viro
2026-02-06 20:58                                 ` setns(2) vs. pivot_root(2) (was Re: [PATCH v2] audit: Avoid excessive dput/dget in audit_context setup and reset paths) Al Viro
2026-02-06 21:09                                   ` Al Viro
2026-02-17 13:12                                     ` Christian Brauner
2026-02-06  8:15                       ` [PATCH v2] audit: Avoid excessive dput/dget in audit_context setup and reset paths Al Viro
2026-02-05  5:22                   ` Al Viro
2026-02-05 13:59                     ` Waiman Long
2026-02-05 17:53                     ` Mateusz Guzik
2026-02-17 13:33                       ` Christian Brauner
2026-02-17 13:44                         ` Mateusz Guzik

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=20260205235351.GU3183987@ZenIV \
    --to=viro@zeniv.linux.org.uk \
    --cc=audit@vger.kernel.org \
    --cc=brauner@kernel.org \
    --cc=eparis@redhat.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=llong@redhat.com \
    --cc=paul@paul-moore.com \
    --cc=rgb@redhat.com \
    --cc=rrobaina@redhat.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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox