[PATCH V1] scsi: ufs: qcom : Fix NULL pointer dereference in ufs_qcom_setup_clocks

[Nitin Rawat]

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:

[    6.448070] Unable to handle kernel NULL pointer dereference at
virtual address 0000000000000000
[    6.448449] ufs_qcom_setup_clocks+0x28/0x148 ufs_qcom (P)
[    6.448466] ufshcd_setup_clocks (drivers/ufs/core/ufshcd-priv.h:142)
[    6.448477] ufshcd_init (drivers/ufs/core/ufshcd.c:9468)
[    6.448485] ufshcd_pltfrm_init (drivers/ufs/host/ufshcd-pltfrm.c:504)
[    6.448495] ufs_qcom_probe+0x28/0x68 ufs_qcom
[    6.448508] platform_probe (drivers/base/platform.c:1404)
[    6.448519] really_probe (drivers/base/dd.c:579 drivers/base/dd.c:657)
[    6.448526] __driver_probe_device (drivers/base/dd.c:799)
[    6.448532] driver_probe_device (drivers/base/dd.c:829)
[    6.448539] __driver_attach (drivers/base/dd.c:1216)
[    6.448545] bus_for_each_dev (drivers/base/bus.c:370)
[    6.448556] driver_attach (drivers/base/dd.c:1234)
[    6.448567] bus_add_driver (drivers/base/bus.c:678)
[    6.448577] driver_register (drivers/base/driver.c:249)
[    6.448584] __platform_driver_register (drivers/base/platform.c:868)
[    6.448592] ufs_qcom_pltform_init+0x28/0xff8 ufs_qcom
[    6.448605] do_one_initcall (init/main.c:1274)
[    6.448615] do_init_module (kernel/module/main.c:3041)
[    6.448626] load_module (kernel/module/main.c:3511)
[    6.448635] init_module_from_file (kernel/module/main.c:3704)
[    6.448644] __arm64_sys_finit_module (kernel/module/main.c:3715.

Fixes: 77d2fa54a945 ("scsi: ufs: qcom : Refactor phy_power_on/off calls")

Tested-by: Naresh Kamboju <naresh.kamboju@xxxxxxxxxx>
Reported-by: Aishwarya <aishwarya.tcv@xxxxxxx>
Closes: https://lore.kernel.org/lkml/20250620214408.11028-1-aishwarya.tcv@xxxxxxx/
Reported-by: Naresh Kamboju <naresh.kamboju@xxxxxxxxxx>
Closes: https://lore.kernel.org/linux-scsi/CA+G9fYuFQ2dBvYm1iB6rbwT=4b1c8e4NJ3yxqFPGZGUKH3GmMA@xxxxxxxxxxxxxx/T/#t
Co-developed-by: Ram Kumar Dwivedi <quic_rdwivedi@xxxxxxxxxxx>
Signed-off-by: Ram Kumar Dwivedi <quic_rdwivedi@xxxxxxxxxxx>
Signed-off-by: Nitin Rawat <quic_nitirawa@xxxxxxxxxxx>
---
 drivers/ufs/host/ufs-qcom.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/ufs/host/ufs-qcom.c b/drivers/ufs/host/ufs-qcom.c
index ba4b2880279c..318dca7fe3d7 100644
--- a/drivers/ufs/host/ufs-qcom.c
+++ b/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) {
--
2.48.1