From: Jason Gunthorpe <jgg@ziepe.ca>
To: l1za0.sec@gmail.com
Cc: kevin.tian@intel.com, joro@8bytes.org, will@kernel.org,
robin.murphy@arm.com, iommu@lists.linux.dev,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] iommufd: fix slab-use-after-free read in iommufd_ioas_unmap
Date: Tue, 21 Apr 2026 10:57:40 -0300 [thread overview]
Message-ID: <20260421135740.GI3611611@ziepe.ca> (raw)
In-Reply-To: <20260421134719.33801-1-l1za0.sec@gmail.com>
On Tue, Apr 21, 2026 at 09:47:05PM +0800, l1za0.sec@gmail.com wrote:
> From: Haocheng Yu <l1za0.sec@gmail.com>
>
> A KASAN: slab-use-after-free read in iommufd_ioas_unmap is reported
> by a modified Syzkaller-based kernel fuzzing tool we developed.
Please don't submit bug reports without validating them on the latest
kernel. This was fixed 2 years ago:
commit 6f9c4d8c468c189d6dc470324bd52955f8aa0a10
Author: Jason Gunthorpe <jgg@ziepe.ca>
Date: Sun Nov 12 15:44:08 2023 -0400
iommufd: Do not UAF during iommufd_put_object()
The mixture of kernel and user space lifecycle objects continues to be
complicated inside iommufd. The obj->destroy_rwsem is used to bring order
to the kernel driver destruction sequence but it cannot be sequenced right
with the other refcounts so we end up possibly UAF'ing:
BUG: KASAN: slab-use-after-free in __up_read+0x627/0x750 kernel/locking/rwsem.c:1342
Read of size 8 at addr ffff888073cde868 by task syz-executor934/6535
> base-commit: ffc253263a1375a65fa6c9f62a893e9767fbebfa
This is v6.6. Nobody wants patches and bug reports from v6.6
Jason
prev parent reply other threads:[~2026-04-21 13:57 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-21 13:47 [PATCH] iommufd: fix slab-use-after-free read in iommufd_ioas_unmap l1za0.sec
2026-04-21 13:57 ` Jason Gunthorpe [this message]
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=20260421135740.GI3611611@ziepe.ca \
--to=jgg@ziepe.ca \
--cc=iommu@lists.linux.dev \
--cc=joro@8bytes.org \
--cc=kevin.tian@intel.com \
--cc=l1za0.sec@gmail.com \
--cc=linux-kernel@vger.kernel.org \
--cc=robin.murphy@arm.com \
--cc=will@kernel.org \
/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