scsi: ufs: qcom : Fix NULL pointer dereference in ufs_qcom_setup_clocks

Fix a NULL pointer dereference in ufs_qcom_setup_clocks due to an
uninitialized 'host' variable. The variable 'phy' is now assigned
after confirming 'host' is not NULL.

Call Stack:

Unable to handle kernel NULL pointer dereference at
virtual address 0000000000000000

ufs_qcom_setup_clocks+0x28/0x148 ufs_qcom (P)
ufshcd_setup_clocks (drivers/ufs/core/ufshcd-priv.h:142)
ufshcd_init (drivers/ufs/core/ufshcd.c:9468)
ufshcd_pltfrm_init (drivers/ufs/host/ufshcd-pltfrm.c:504)
ufs_qcom_probe+0x28/0x68 ufs_qcom
platform_probe (drivers/base/platform.c:1404)
really_probe (drivers/base/dd.c:579 drivers/base/dd.c:657)
__driver_probe_device (drivers/base/dd.c:799)
driver_probe_device (drivers/base/dd.c:829)
__driver_attach (drivers/base/dd.c:1216)
bus_for_each_dev (drivers/base/bus.c:370)
driver_attach (drivers/base/dd.c:1234)
bus_add_driver (drivers/base/bus.c:678)
driver_register (drivers/base/driver.c:249)
__platform_driver_register (drivers/base/platform.c:868)
ufs_qcom_pltform_init+0x28/0xff8 ufs_qcom
do_one_initcall (init/main.c:1274)
do_init_module (kernel/module/main.c:3041)
load_module (kernel/module/main.c:3511)
init_module_from_file (kernel/module/main.c:3704)
__arm64_sys_finit_module (kernel/module/main.c:3715.

Reviewed-by: Manivannan Sadhasivam <[email protected]>
Reviewed-by: Neil Armstrong <[email protected]>
Fixes: 77d2fa5 ("scsi: ufs: qcom : Refactor phy_power_on/off calls")
Tested-by: Dmitry Baryshkov <[email protected]>
Tested-by: Naresh Kamboju <[email protected]>
Tested-by: Neil Armstrong <[email protected]>
Reported-by: Aishwarya <[email protected]>
Closes: https://lore.kernel.org/lkml/[email protected]/
Reported-by: Naresh Kamboju <[email protected]>
Closes: https://lore.kernel.org/linux-scsi/CA+G9fYuFQ2dBvYm1iB6rbwT=4b1c8e4NJ3yxqFPGZGUKH3GmMA@mail.gmail.com/T/#t
Co-developed-by: Ram Kumar Dwivedi <[email protected]>
Signed-off-by: Ram Kumar Dwivedi <[email protected]>
Signed-off-by: Nitin Rawat <[email protected]>
Reviewed-by: Martin K. Petersen <[email protected]>
Reported-by: Linux Kernel Functional Testing <[email protected]>
Tested-by: Linux Kernel Functional Testing <[email protected]>
Tested-by: Marek Szyprowski <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Vinod Koul <[email protected]>

Author: Nitin Rawat

drivers/ufs/host/ufs-qcom.c

@@ -1124,7 +1124,7 @@ static int ufs_qcom_setup_clocks(struct ufs_hba *hba, bool on,
 				 enum ufs_notify_change_status status)
 {
 	struct ufs_qcom_host *host = ufshcd_get_variant(hba);
-	struct phy *phy = host->generic_phy;
+	struct phy *phy;
 	int err;
 
 	/*
@@ -1135,6 +1135,8 @@ static int ufs_qcom_setup_clocks(struct ufs_hba *hba, bool on,
 	if (!host)
 		return 0;
 
+	phy = host->generic_phy;
+
 	switch (status) {
 	case PRE_CHANGE:
 		if (on) {