[PATCH v4 1/2] scsi: ufs: Fix a possible NULL pointer issue

Can Guo
2021-01-13T13:58:05Z

During system resume/suspend, hba could be NULL. In this case, do not touch
eh_sem.

Fixes: 88a92d6ae4fe ("scsi: ufs: Serialize eh_work with system PM events and async scan")

Acked-by: Stanley Chu <stanley.chu@mediatek.com>
Signed-off-by: Can Guo <cang@codeaurora.org>
---
drivers/scsi/ufs/ufshcd.c | 17 ++++++++++++++---
1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 53fd59c..969aed9 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -94,6 +94,8 @@
16, 4, buf, __len, false); \
} while (0)

+static bool early_suspend;
+
int ufshcd_dump_regs(struct ufs_hba *hba, size_t offset, size_t len,
const char *prefix)
{
@@ -8953,8 +8955,14 @@ int ufshcd_system_suspend(struct ufs_hba *hba)
int ret = 0;
ktime_t start = ktime_get();

+ if (!hba) {
+ early_suspend = true;
+ return 0;
+ }
+
down(&hba->eh_sem);
- if (!hba || !hba->is_powered)
+
+ if (!hba->is_powered)
return 0;

if ((ufs_get_pm_lvl_to_dev_pwr_mode(hba->spm_lvl) ==
@@ -9002,9 +9010,12 @@ int ufshcd_system_resume(struct ufs_hba *hba)
int ret = 0;
ktime_t start = ktime_get();

- if (!hba) {
- up(&hba->eh_sem);
+ if (!hba)
return -EINVAL;
+
+ if (unlikely(early_suspend)) {
+ early_suspend = false;
+ down(&hba->eh_sem);
}

if (!hba->is_powered || pm_runtime_suspended(hba->dev))
--
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project.