public inbox for [email protected]
 help / color / mirror / Atom feed
From: Al Viro <[email protected]>
To: Christian Brauner <[email protected]>
Cc: Jens Axboe <[email protected]>,
	syzbot <[email protected]>,
	[email protected], [email protected],
	[email protected], [email protected]
Subject: Re: [syzbot] WARNING in mntput_no_expire (2)
Date: Tue, 6 Apr 2021 14:23:28 +0000	[thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>

On Tue, Apr 06, 2021 at 02:15:01PM +0000, Al Viro wrote:

> I'm referring to the fact that your diff is with an already modified path_lookupat()
> _and_ those modifications have managed to introduce a bug your patch reverts.
> No terminate_walk() paired with that path_init() failure, i.e. path_init() is
> responsible for cleanups on its (many) failure exits...

I can't tell without seeing the variant your diff is against, but at a guess
it had a non-trivial amount of trouble with missed rcu_read_unlock() in
cases when path_init() fails after having done rcu_read_lock().  For trivial
testcase, consider passing -1 for dfd, so that it would fail with -EBADF.
Or passing 0 for dfd and "blah" for name (assuming your stdin is not a directory).
Sure, you could handle those in path_init() (or delay grabbing rcu_read_lock()
in there, spreading it in a bunch of branches), but duplicated cleanup logics
for a bunch of failure exits is asking for trouble.

  reply	other threads:[~2021-04-06 14:23 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <[email protected]>
2021-04-01 15:45 ` [syzbot] WARNING in mntput_no_expire (2) Christian Brauner
2021-04-01 16:09   ` Jens Axboe
2021-04-01 17:46     ` Christian Brauner
2021-04-01 17:59       ` Christian Brauner
2021-04-01 19:11         ` Al Viro
2021-04-04  2:34           ` Al Viro
2021-04-04  2:38             ` Al Viro
2021-04-04 11:34             ` Christian Brauner
2021-04-04 15:56               ` Al Viro
2021-04-04 16:40                 ` Christian Brauner
2021-04-04 16:44                   ` Al Viro
2021-04-04 17:05                     ` Christian Brauner
2021-04-04 18:50                       ` Al Viro
2021-04-04 20:17                         ` Al Viro
2021-04-05 11:44                           ` Christian Brauner
2021-04-05 16:18                             ` Al Viro
2021-04-05 17:08                               ` Christian Brauner
2021-04-05 18:23                                 ` Al Viro
2021-04-05 18:28                                   ` Al Viro
2021-04-05 20:07                                     ` Christian Brauner
2021-04-06  1:38                                       ` Al Viro
2021-04-06  2:24                                         ` Al Viro
2021-04-06 12:35                                         ` Christian Brauner
2021-04-06 13:13                                           ` Al Viro
2021-04-06 13:22                                             ` Christian Brauner
2021-04-06 14:15                                               ` Al Viro
2021-04-06 14:23                                                 ` Al Viro [this message]
2021-04-06 15:37                                                   ` Jens Axboe
2021-04-06 14:46                                                 ` Christian Brauner
2021-04-04 16:52                   ` Christian Brauner
2021-04-04 16:55                     ` Christian Brauner

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 \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    /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