linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
To: Shuah Khan <skhan@linuxfoundation.org>,
	Hillf Danton <hdanton@sina.com>,
	syzbot <syzbot+95ce4b142579611ef0a9@syzkaller.appspotmail.com>
Cc: linux-kernel@vger.kernel.org,
	linux-security-module@vger.kernel.org,
	Andrey Konovalov <andreyknvl@google.com>,
	Valentina Manea <valentina.manea.m@gmail.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	syzkaller-bugs@googlegroups.com
Subject: Re: general protection fault in tomoyo_socket_sendmsg_permission
Date: Fri, 29 Jan 2021 14:48:36 +0900	[thread overview]
Message-ID: <9bdd3f10-bddb-bd87-d7ad-b4b706477006@i-love.sakura.ne.jp> (raw)
In-Reply-To: <2b70d360-a293-4acb-ea6c-2badda5e8b8b@linuxfoundation.org>

On 2021/01/29 4:05, Shuah Khan wrote:
> The reason I don't like adding printk's is this is a race condition
> and as a result time sensitive. Adding printks in the path will not
> help debug this issue. It will make it harder to reproduce the problem.

Not always. Adding printk() might make it easier to reproduce the problem.

> 
> I am unable to reproduce the problem using the reproducer and running multiple instances of the reproducer.

Since syzkaller cannot find a reproducer for "general protection fault in
tomoyo_socket_sendmsg_permission", and you cannot reproduce other problem
using reproducer, trying to obtain some clue via printing messages by asking
syzkaller to try debug patch can be very helpful.

Since "general protection fault in tomoyo_socket_sendmsg_permission" is caused by
unexpectedly resetting ud->tcp_socket to NULL without waiting for tx thread to
terminate, tracing the ordering of events is worth knowing. Even adding
schedule_timeout_uninterruptible() to before kernel_sendmsg() might help.


  parent reply	other threads:[~2021-01-29  5:50 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-13  7:21 general protection fault in tomoyo_socket_sendmsg_permission syzbot
     [not found] ` <20201113120055.11748-1-hdanton@sina.com>
2020-11-13 17:14   ` Shuah Khan
2021-01-28  6:09     ` Tetsuo Handa
     [not found]       ` <2b70d360-a293-4acb-ea6c-2badda5e8b8b@linuxfoundation.org>
2021-01-29  5:48         ` Tetsuo Handa [this message]
     [not found]           ` <6b8da36f-a994-7604-77f4-52e29434605f@linuxfoundation.org>
2021-01-29 17:08             ` Tetsuo Handa
2021-01-29 21:18               ` Shuah Khan
2021-01-30  2:25                 ` Tetsuo Handa
2021-02-10 18:17                   ` Shuah Khan
2021-02-10 19:07                     ` Tetsuo Handa
2021-02-10 19:29                       ` Shuah Khan
2021-02-11  1:14                         ` Tetsuo Handa
2021-02-12  1:34                           ` Shuah Khan
2021-02-12  2:22                             ` Tetsuo Handa
2021-02-12  4:58                               ` Tetsuo Handa
2021-02-12 20:02                                 ` Shuah Khan
2021-02-13 10:02                                   ` Tetsuo Handa
2021-02-13 10:10                                     ` Greg Kroah-Hartman
2021-02-13 10:10                                     ` Greg Kroah-Hartman

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=9bdd3f10-bddb-bd87-d7ad-b4b706477006@i-love.sakura.ne.jp \
    --to=penguin-kernel@i-love.sakura.ne.jp \
    --cc=andreyknvl@google.com \
    --cc=gregkh@linuxfoundation.org \
    --cc=hdanton@sina.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-security-module@vger.kernel.org \
    --cc=skhan@linuxfoundation.org \
    --cc=syzbot+95ce4b142579611ef0a9@syzkaller.appspotmail.com \
    --cc=syzkaller-bugs@googlegroups.com \
    --cc=valentina.manea.m@gmail.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;
as well as URLs for NNTP newsgroup(s).