On 2021/11/22 11:03, libaokun (A) wrote:
> 在 2021/11/20 20:01, Sergei Shtylyov 写道:
>> Hello!
>>
>> On 20.11.2021 6:34, Baokun Li wrote:
>>
>>> When the `rmmod sata_fsl.ko` command is executed in the PPC64 GNU/Linux,
>>> a bug is reported:
>>> ==================================================================
>>> BUG: Unable to handle kernel data access on read at 0x80000800805b502c
>>> Oops: Kernel access of bad area, sig: 11 [#1]
>>> NIP [c0000000000388a4] .ioread32+0x4/0x20
>>> LR [80000000000c6034] .sata_fsl_port_stop+0x44/0xe0 [sata_fsl]
>>> Call Trace:
>>> .free_irq+0x1c/0x4e0 (unreliable)
>>> .ata_host_stop+0x74/0xd0 [libata]
>>> .release_nodes+0x330/0x3f0
>>> .device_release_driver_internal+0x178/0x2c0
>>> .driver_detach+0x64/0xd0
>>> .bus_remove_driver+0x70/0xf0
>>> .driver_unregister+0x38/0x80
>>> .platform_driver_unregister+0x14/0x30
>>> .fsl_sata_driver_exit+0x18/0xa20 [sata_fsl]
>>> .__se_sys_delete_module+0x1ec/0x2d0
>>> .system_call_exception+0xfc/0x1f0
>>> system_call_common+0xf8/0x200
>>> ==================================================================
>>>
>>> The triggering of the BUG is shown in the following stack:
>>>
>>> driver_detach
>>> device_release_driver_internal
>>> __device_release_driver
>>> drv->remove(dev) --> platform_drv_remove/platform_remove
>>> drv->remove(dev) --> sata_fsl_remove
>>> iounmap(host_priv->hcr_base); <---- unmap
>>> kfree(host_priv); <---- free
>>> devres_release_all
>>> release_nodes
>>> dr->node.release(dev, dr->data) --> ata_host_stop
>>> ap->ops->port_stop(ap) --> sata_fsl_port_stop
>>> ioread32(hcr_base + HCONTROL) <---- UAF
>>> host->ops->host_stop(host)
>>>
>>> The iounmap(host_priv->hcr_base) and kfree(host_priv) commands should
>>
>> s/commands/functions/?
>
> OK! I'm going to modify this in V3.
>
>
>>
>>> not be executed in drv->remove. These commands should be executed in
>>> host_stop after port_stop. Therefore, we move these commands to the
>>> new function sata_fsl_host_stop and bind the new function to host_stop
>>> by referring to achi.
>>
>> You mean AHCI? I don't see where you reference ahci (or achi)...
>
> Yes, it's AHCI, I'm sorry for a spelling error here..
>
> ahci_platform_ops in drivers/ata/libahci_platform.c
>
>
>>
>>> Reported-by: Hulk Robot <hulkci@xxxxxxxxxx>
>>> Signed-off-by: Baokun Li <libaokun1@xxxxxxxxxx>
>>
>> Doesn't this need to go into the stable trees?
>
>
> I felt it was needed because the bug was triggered in a very simple way,
>
> although PPC linux is rare these days.
>
> And I will add
>
> Fixes: faf0b2e5afe7 ("drivers/ata: add support to Freescale 3.0Gbps SATA Controller").
Also add:
Cc: stable@xxxxxxxxxxxxxxx
>
>>
>>> ---
>>> drivers/ata/sata_fsl.c | 17 ++++++++++++++---
>>> 1 file changed, 14 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/drivers/ata/sata_fsl.c b/drivers/ata/sata_fsl.c
>>> index e5838b23c9e0..30759fd1c3a2 100644
>>> --- a/drivers/ata/sata_fsl.c
>>> +++ b/drivers/ata/sata_fsl.c
>>> @@ -1430,12 +1430,25 @@ static struct ata_port_operations sata_fsl_ops = {
>>> .pmp_detach = sata_fsl_pmp_detach,
>>> };
>>> +static void sata_fsl_host_stop(struct ata_host *host)
>>> +{
>>> + struct sata_fsl_host_priv *host_priv = host->private_data;
>>> +
>>> + iounmap(host_priv->hcr_base);
>>> + kfree(host_priv);
>>> +}
>>> +
>>> +static struct ata_port_operations sata_fsl_platform_ops = {
>>> + .inherits = &sata_fsl_ops,
>>> + .host_stop = sata_fsl_host_stop,
>>
>> Why not just add it to the initializer for sata_fsl_ops?
>
>
> This is the AHCI of the reference.
>
> Most ATA drivers add host_stop to to the initializer for xxx_platform_ops,
>
> such as ahci_platform_ops, ahci_brcm_platform_ops, and ahci_imx_ops.
>
> It feels like this separates the port operation from the host operation,
>
> making the hierarchy of the code clearer.
>
>
>>
>> [...]
>>
>> MBR, Sergei
>> .
>
>
> Thank you very much for your advice.
>
> If there's nothing else to modify, I'll send a patch V3.
>
> --
> With Best Regards,
> Baokun Li
> .
>
--
Damien Le Moal
Western Digital Research
