From: Jason Gunthorpe <jgg@ziepe.ca>
To: Hillf Danton <hdanton@sina.com>
Cc: syzbot <syzbot+a929647172775e335941@syzkaller.appspotmail.com>,
chuck.lever@oracle.com, dledford@redhat.com, leon@kernel.org,
linux-kernel@vger.kernel.org, linux-rdma@vger.kernel.org,
parav@mellanox.com, Markus Elfring <Markus.Elfring@web.de>,
syzkaller-bugs@googlegroups.com
Subject: Re: KASAN: use-after-free Read in addr_handler (2)
Date: Sat, 27 Jun 2020 19:25:27 -0300 [thread overview]
Message-ID: <20200627222527.GC25301@ziepe.ca> (raw)
In-Reply-To: <20200627130205.16900-1-hdanton@sina.com>
On Sat, Jun 27, 2020 at 09:02:05PM +0800, Hillf Danton wrote:
> > So, to hit this syzkaller one of these must have happened:
> > 1) rdma_addr_cancel() didn't work and the process_one_work() is still
> > runnable/running
>
> What syzbot reported indicates that the kworker did survive not only
> canceling work but the handler_mutex, despite it's a sync cancel that
> waits for the work to complete.
The syzbot report doesn't confirm that the cancel work was actaully
called.
The most likely situation is that it was skipped because of the state
mangling the patch fixes..
> > 2) The state changed away from RDMA_CM_ADDR_QUERY without doing
> > rdma_addr_cancel()
>
> The cancel does cover the query state in the reported case, and have
> difficult time working out what's in the patch below preventing the
> work from going across the line the sync cancel draws. That's the
> question we can revisit once there is a reproducer available.
rdma-cm never seems to get reproducers from syzkaller
Jason
next prev parent reply other threads:[~2020-06-27 22:25 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-10 17:02 KASAN: use-after-free Read in addr_handler (2) syzbot
[not found] ` <20200614085321.8740-1-hdanton@sina.com>
2020-06-27 0:45 ` Jason Gunthorpe
2020-06-27 2:38 ` [PATCH] RDMA/cma: Execute rdma_cm destruction from a handler properly kernel test robot
[not found] ` <20200627130205.16900-1-hdanton@sina.com>
2020-06-27 22:25 ` Jason Gunthorpe [this message]
2020-06-29 14:42 ` KASAN: use-after-free Read in addr_handler (2) Dmitry Vyukov
2020-06-29 17:27 ` Dmitry Vyukov
2020-06-29 19:22 ` Jason Gunthorpe
2020-06-29 19:41 ` Dmitry Vyukov
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=20200627222527.GC25301@ziepe.ca \
--to=jgg@ziepe.ca \
--cc=Markus.Elfring@web.de \
--cc=chuck.lever@oracle.com \
--cc=dledford@redhat.com \
--cc=hdanton@sina.com \
--cc=leon@kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-rdma@vger.kernel.org \
--cc=parav@mellanox.com \
--cc=syzbot+a929647172775e335941@syzkaller.appspotmail.com \
--cc=syzkaller-bugs@googlegroups.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).