On 07/11/2022 11:54, Yang Yingliang wrote:
If transport_add_device() fails in sas_phy_add(), but it's not handled,
The wording is hard to understand here. Omit "but" and it's becomes a
bit more readable...
it will lead kernel crash because of trying to delete not added device
in transport_remove_device() called from sas_remove_host().
Unable to handle kernel NULL pointer dereference at virtual address 0000000000000108
CPU: 61 PID: 42829 Comm: rmmod Kdump: loaded Tainted: G W 6.1.0-rc1+ #173
pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : device_del+0x54/0x3d0
lr : device_del+0x37c/0x3d0
Call trace:
device_del+0x54/0x3d0
attribute_container_class_device_del+0x28/0x38
transport_remove_classdev+0x6c/0x80
attribute_container_device_trigger+0x108/0x110
transport_remove_device+0x28/0x38
sas_phy_delete+0x30/0x60 [scsi_transport_sas]
do_sas_phy_delete+0x6c/0x80 [scsi_transport_sas]
device_for_each_child+0x68/0xb0
sas_remove_children+0x40/0x50 [scsi_transport_sas]
sas_remove_host+0x20/0x38 [scsi_transport_sas]
hisi_sas_remove+0x40/0x68 [hisi_sas_main]
hisi_sas_v2_remove+0x20/0x30 [hisi_sas_v2_hw]
platform_remove+0x2c/0x60
Fix this by checking and handling return value of transport_add_device()
in sas_phy_add().
Fixes: c7ebbbce366c ("[SCSI] SAS transport class")
Suggested-by: John Garry <john.g.garry@xxxxxxxxxx>
Signed-off-by: Yang Yingliang <yangyingliang@xxxxxxxxxx>
Apart from comment about commit message:
Reviewed-by: John Garry <john.g.garry@xxxxxxxxxx>
---
v1 -> v2:
Update title and refactor the error handling suggested by John.
---
drivers/scsi/scsi_transport_sas.c | 13 +++++++++----
1 file changed, 9 insertions(+), 4 deletions(-)
diff --git a/drivers/scsi/scsi_transport_sas.c b/drivers/scsi/scsi_transport_sas.c
index 2f88c61216ee..74b99f2b0b74 100644
--- a/drivers/scsi/scsi_transport_sas.c
+++ b/drivers/scsi/scsi_transport_sas.c
@@ -722,12 +722,17 @@ int sas_phy_add(struct sas_phy *phy)
int error;
error = device_add(&phy->dev);
- if (!error) {
- transport_add_device(&phy->dev);
- transport_configure_device(&phy->dev);
+ if (error)
+ return error;
+
+ error = transport_add_device(&phy->dev);
+ if (error) {
+ device_del(&phy->dev);
+ return error;
}
+ transport_configure_device(&phy->dev);
- return error;
+ return 0;
}
EXPORT_SYMBOL(sas_phy_add);
