The RTC update work involves runtime resuming the UFS controller. Hence, only start the RTC update work after runtime power management in the UFS driver has been fully initialized. This patch fixes the following kernel crash:

Internal error: Oops: 0000000096000006 [#1] PREEMPT SMP Workqueue: events ufshcd_rtc_work Call trace: _raw_spin_lock_irqsave+0x34/0x8c (P) pm_runtime_get_if_active+0x24/0x9c (L) pm_runtime_get_if_active+0x24/0x9c ufshcd_rtc_work+0x138/0x1b4 process_one_work+0x148/0x288 worker_thread+0x2cc/0x3d4 kthread+0x110/0x114 ret_from_fork+0x10/0x20

Reported-by: Neil Armstrong neil.armstrong@linaro.org Closes: https://lore.kernel.org/linux-scsi/0c0bc528-fdc2-4106-bc99-f23ae377f6f5@lina... Fixes: 6bf999e0eb41 ("scsi: ufs: core: Add UFS RTC support") Cc: Bean Huo beanhuo@micron.com Cc: stable@vger.kernel.org Signed-off-by: Bart Van Assche bvanassche@acm.org --- drivers/ufs/core/ufshcd.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c index 585557eaa9a2..ed82ff329314 100644 --- a/drivers/ufs/core/ufshcd.c +++ b/drivers/ufs/core/ufshcd.c @@ -8633,6 +8633,14 @@ static int ufshcd_add_lus(struct ufs_hba *hba) ufshcd_init_clk_scaling_sysfs(hba); }

+ /* + * The RTC update code accesses the hba->ufs_device_wlun->sdev_gendev + * pointer and hence must only be started after the WLUN pointer has + * been initialized by ufshcd_scsi_add_wlus(). + */ + schedule_delayed_work(&hba->ufs_rtc_update_work, + msecs_to_jiffies(UFS_RTC_UPDATE_INTERVAL_MS)); + ufs_bsg_probe(hba); scsi_scan_host(hba->host);

@@ -8727,8 +8735,6 @@ static int ufshcd_post_device_init(struct ufs_hba *hba) ufshcd_force_reset_auto_bkops(hba);

ufshcd_set_timestamp_attr(hba); - schedule_delayed_work(&hba->ufs_rtc_update_work, - msecs_to_jiffies(UFS_RTC_UPDATE_INTERVAL_MS));

if (!hba->max_pwr_info.is_valid) return 0;