From: Jason Gunthorpe <jgg@ziepe.ca>
To: syzbot <syzbot+45f6cae2ca8c1f71e529@syzkaller.appspotmail.com>
Cc: iommu@lists.linux.dev, joro@8bytes.org, kevin.tian@intel.com,
linux-kernel@vger.kernel.org, robin.murphy@arm.com,
syzkaller-bugs@googlegroups.com, will@kernel.org
Subject: Re: [syzbot] [iommu?] KASAN: slab-use-after-free Read in iommufd_ioas_iova_ranges
Date: Wed, 25 Oct 2023 15:32:20 -0300 [thread overview]
Message-ID: <20231025183220.GQ691768@ziepe.ca> (raw)
In-Reply-To: <000000000000d621b406088a2f55@google.com>
On Wed, Oct 25, 2023 at 06:11:01AM -0700, syzbot wrote:
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit: c3200081020d Merge tag 'block-6.6-2023-10-20' of git://git..
> git tree: upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=15013471680000
> kernel config: https://syzkaller.appspot.com/x/.config?x=849fe52ba7c6d78a
> dashboard link: https://syzkaller.appspot.com/bug?extid=45f6cae2ca8c1f71e529
> compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
>
> Unfortunately, I don't have any reproducer for this issue yet.
>
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/caa5c1eed3ec/disk-c3200081.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/7990a3a9f71e/vmlinux-c3200081.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/015551ac9acc/bzImage-c3200081.xz
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+45f6cae2ca8c1f71e529@syzkaller.appspotmail.com
>
> ==================================================================
> BUG: KASAN: slab-use-after-free in __up_read+0xb3/0x690 kernel/locking/rwsem.c:1342
> Read of size 8 at addr ffff8880283c9068 by task syz-executor.2/30372
Oh *ugh* I knew about this limitation once and forgot about it
apparently.
CPU 0 CPU1
down_read()
up_read()
down_write()
up_write()
kfree()
[..]
tail portion of up_read()
I suppose the rwsem should be turned into a refcount and completion
Jason
next prev parent reply other threads:[~2023-10-25 18:32 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-25 13:11 [syzbot] [iommu?] KASAN: slab-use-after-free Read in iommufd_ioas_iova_ranges syzbot
2023-10-25 18:32 ` Jason Gunthorpe [this message]
[not found] ` <20231026110502.2046-1-hdanton@sina.com>
2023-10-26 11:41 ` Jason Gunthorpe
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