From: Jason Gunthorpe <jgg@ziepe.ca>
To: Hillf Danton <hdanton@sina.com>
Cc: syzbot <syzbot+478fd0d54412b8759e0d@syzkaller.appspotmail.com>,
dledford@redhat.com, leon@kernel.org,
linux-kernel@vger.kernel.org, linux-rdma@vger.kernel.org,
michal.kalderon@marvell.com, syzkaller-bugs@googlegroups.com,
yishaih@mellanox.com
Subject: Re: KASAN: use-after-free Read in ib_uverbs_remove_one
Date: Fri, 29 May 2020 10:09:54 -0300 [thread overview]
Message-ID: <20200529130954.GA21651@ziepe.ca> (raw)
In-Reply-To: <20200529083126.15808-1-hdanton@sina.com>
On Fri, May 29, 2020 at 04:31:26PM +0800, Hillf Danton wrote:
> Hold another grab to dev to prevent it from going home before work gets
> done with it.
>
> +++ b/drivers/infiniband/core/uverbs_main.c
> @@ -1152,6 +1152,8 @@ static int ib_uverbs_add_one(struct ib_d
> device->ops.mmap ? &uverbs_mmap_fops : &uverbs_fops);
> uverbs_dev->cdev.owner = THIS_MODULE;
>
> + /* pair with put_device() in ib_uverbs_remove_one() */
> + get_device(&uverbs_dev->dev);
> ret = cdev_device_add(&uverbs_dev->cdev, &uverbs_dev->dev);
> if (ret)
> goto err_uapi;
Doesn't look right, the put_device() in uverbs_remove_one() pairs with
the device_initialize() in this function.
The only thing I can think of is we called remove_once twice
somehow or had an extra put on some error path. But I couldn't find
any flow that would do either of those things
Jason
next prev parent reply other threads:[~2020-05-29 13:29 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-28 14:33 KASAN: use-after-free Read in ib_uverbs_remove_one syzbot
[not found] ` <20200529083126.15808-1-hdanton@sina.com>
2020-05-29 13:09 ` Jason Gunthorpe [this message]
2020-05-30 0:13 ` Jason Gunthorpe
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