On 11/7/22 21:59, Yang Yingliang wrote:
> If transport_add_device() fails in ata_tport_add(), it's not handled,
> it will lead kernel crash because of trying to delete not added device
> in transport_remove_device() called from ata_tport_delete().
Simplify your sentences to make them easier to understand:
In ata_tport_add(), the return value of transport_add_device() is not
checked. As a result, another error after that function call leads to a
kernel crash (null pointer dereference) because
transport_remove_device() is called to remove a device that was not added.
Please fix this. The patch itself is OK.
>
> Unable to handle kernel NULL pointer dereference at virtual address 00000000000000d0
> CPU: 12 PID: 13605 Comm: rmmod Kdump: loaded Tainted: G W 6.1.0-rc3+ #8
> pstate: 60400009 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
> pc : device_del+0x48/0x39c
> lr : device_del+0x44/0x39c
> Call trace:
> device_del+0x48/0x39c
> attribute_container_class_device_del+0x28/0x40
> transport_remove_classdev+0x60/0x7c
> attribute_container_device_trigger+0x118/0x120
> transport_remove_device+0x20/0x30
> ata_tport_delete+0x34/0x60 [libata]
> ata_port_detach+0x148/0x1b0 [libata]
> ata_pci_remove_one+0x50/0x80 [libata]
> ahci_remove_one+0x4c/0x8c [ahci]
>
> Fix this by checking and handling return value of transport_add_device()
> in ata_tport_add().
>
> Fixes: d9027470b886 ("[libata] Add ATA transport class")
> Signed-off-by: Yang Yingliang <yangyingliang@xxxxxxxxxx>
> ---
> drivers/ata/libata-transport.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/ata/libata-transport.c b/drivers/ata/libata-transport.c
> index 105da3ec5eaa..ef53bdfbcbb2 100644
> --- a/drivers/ata/libata-transport.c
> +++ b/drivers/ata/libata-transport.c
> @@ -301,7 +301,9 @@ int ata_tport_add(struct device *parent,
> pm_runtime_enable(dev);
> pm_runtime_forbid(dev);
>
> - transport_add_device(dev);
> + error = transport_add_device(dev);
> + if (error)
> + goto tport_transport_add_err;
> transport_configure_device(dev);
>
> error = ata_tlink_add(&ap->link);
> @@ -312,6 +314,7 @@ int ata_tport_add(struct device *parent,
>
> tport_link_err:
> transport_remove_device(dev);
> + tport_transport_add_err:
> device_del(dev);
>
> tport_err:
--
Damien Le Moal
Western Digital Research
