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Message-ID: <PH0PR12MB54811F4CC671312DFB2FACCDDC609@PH0PR12MB5481.namprd12.prod.outlook.com>
Date: Tue, 23 Nov 2021 03:12:31 +0000
From: Parav Pandit <parav@...dia.com>
To: "Longpeng(Mike)" <longpeng2@...wei.com>,
"mst@...hat.com" <mst@...hat.com>,
"jasowang@...hat.com" <jasowang@...hat.com>
CC: "sgarzare@...hat.com" <sgarzare@...hat.com>,
Max Gurtovoy <mgurtovoy@...dia.com>,
"virtualization@...ts.linux-foundation.org"
<virtualization@...ts.linux-foundation.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"arei.gonglei@...wei.com" <arei.gonglei@...wei.com>
Subject: RE: [PATCH] vdpa_sim: avoid putting an uninitialized iova_domain
> From: Longpeng(Mike) <longpeng2@...wei.com>
> Sent: Monday, November 22, 2021 5:52 PM
>
> From: Longpeng <longpeng2@...wei.com>
>
> The system will crash if we put an uninitialized iova_domain, this could
> happen when an error occurs before initializing the iova_domain in
> vdpasim_create().
>
> BUG: kernel NULL pointer dereference, address: 0000000000000000 ...
> RIP: 0010:__cpuhp_state_remove_instance+0x96/0x1c0
> ...
> Call Trace:
> <TASK>
> put_iova_domain+0x29/0x220
> vdpasim_free+0xd1/0x120 [vdpa_sim]
> vdpa_release_dev+0x21/0x40 [vdpa]
> device_release+0x33/0x90
> kobject_release+0x63/0x160
> vdpasim_create+0x127/0x2a0 [vdpa_sim]
> vdpasim_net_dev_add+0x7d/0xfe [vdpa_sim_net]
> vdpa_nl_cmd_dev_add_set_doit+0xe1/0x1a0 [vdpa]
> genl_family_rcv_msg_doit+0x112/0x140
> genl_rcv_msg+0xdf/0x1d0
> ...
>
> So we must make sure the iova_domain is already initialized before put it.
>
> In addition, we may get the following warning in this case:
> WARNING: ... drivers/iommu/iova.c:344 iova_cache_put+0x58/0x70
>
> So we must make sure the iova_cache_put() is invoked only if the
> iova_cache_get() is already invoked. Let's fix it together.
>
> Signed-off-by: Longpeng <longpeng2@...wei.com>
Can you please add the fixes tag here so that older kernels can take this fix?
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