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Subject[PATCH AUTOSEL 4.19 199/205] scsi: ufshcd: Fix NULL pointer dereference for in ufshcd_init
Date
From: Vivek Gautam <vivek.gautam@codeaurora.org>

[ Upstream commit eebcc19646489b68399ce7b35d9c38eb9f4ec40f ]

Error paths in ufshcd_init() ufshcd_hba_exit() killed clk_scaling workqueue
when the workqueue is actually created quite late in ufshcd_init(). So, we
end up getting NULL pointer dereference in such error paths. Fix this by
moving clk_scaling initialization and kill codes to two separate methods, and
call them at required places.

Fixes: 401f1e4490ee ("scsi: ufs: don't suspend clock scaling during clock
gating")

Signed-off-by: Vivek Gautam <vivek.gautam@codeaurora.org>
Cc: Bjorn Andersson <bjorn.andersson@linaro.org>
Cc: Subhash Jadavani <subhashj@codeaurora.org>
Cc: Matthias Kaehlcke <mka@chromium.org>
Cc: Evan Green <evgreen@chromium.org>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Evan Green <evgreen@chromium.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/scsi/ufs/ufshcd.c | 53 +++++++++++++++++++++++++--------------
1 file changed, 34 insertions(+), 19 deletions(-)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 4aaba3e030554..8bce755e0f5bc 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -1772,6 +1772,34 @@ out:
return count;
}

+static void ufshcd_init_clk_scaling(struct ufs_hba *hba)
+{
+ char wq_name[sizeof("ufs_clkscaling_00")];
+
+ if (!ufshcd_is_clkscaling_supported(hba))
+ return;
+
+ INIT_WORK(&hba->clk_scaling.suspend_work,
+ ufshcd_clk_scaling_suspend_work);
+ INIT_WORK(&hba->clk_scaling.resume_work,
+ ufshcd_clk_scaling_resume_work);
+
+ snprintf(wq_name, sizeof(wq_name), "ufs_clkscaling_%d",
+ hba->host->host_no);
+ hba->clk_scaling.workq = create_singlethread_workqueue(wq_name);
+
+ ufshcd_clkscaling_init_sysfs(hba);
+}
+
+static void ufshcd_exit_clk_scaling(struct ufs_hba *hba)
+{
+ if (!ufshcd_is_clkscaling_supported(hba))
+ return;
+
+ destroy_workqueue(hba->clk_scaling.workq);
+ ufshcd_devfreq_remove(hba);
+}
+
static void ufshcd_init_clk_gating(struct ufs_hba *hba)
{
char wq_name[sizeof("ufs_clk_gating_00")];
@@ -6676,6 +6704,7 @@ out:
*/
if (ret && !ufshcd_eh_in_progress(hba) && !hba->pm_op_in_progress) {
pm_runtime_put_sync(hba->dev);
+ ufshcd_exit_clk_scaling(hba);
ufshcd_hba_exit(hba);
}

@@ -7223,12 +7252,9 @@ static void ufshcd_hba_exit(struct ufs_hba *hba)
ufshcd_variant_hba_exit(hba);
ufshcd_setup_vreg(hba, false);
ufshcd_suspend_clkscaling(hba);
- if (ufshcd_is_clkscaling_supported(hba)) {
+ if (ufshcd_is_clkscaling_supported(hba))
if (hba->devfreq)
ufshcd_suspend_clkscaling(hba);
- destroy_workqueue(hba->clk_scaling.workq);
- ufshcd_devfreq_remove(hba);
- }
ufshcd_setup_clocks(hba, false);
ufshcd_setup_hba_vreg(hba, false);
hba->is_powered = false;
@@ -7908,6 +7934,7 @@ void ufshcd_remove(struct ufs_hba *hba)
ufshcd_disable_intr(hba, hba->intr_mask);
ufshcd_hba_stop(hba, true);

+ ufshcd_exit_clk_scaling(hba);
ufshcd_exit_clk_gating(hba);
if (ufshcd_is_clkscaling_supported(hba))
device_remove_file(hba->dev, &hba->clk_scaling.enable_attr);
@@ -8079,6 +8106,8 @@ int ufshcd_init(struct ufs_hba *hba, void __iomem *mmio_base, unsigned int irq)

ufshcd_init_clk_gating(hba);

+ ufshcd_init_clk_scaling(hba);
+
/*
* In order to avoid any spurious interrupt immediately after
* registering UFS controller interrupt handler, clear any pending UFS
@@ -8117,21 +8146,6 @@ int ufshcd_init(struct ufs_hba *hba, void __iomem *mmio_base, unsigned int irq)
goto out_remove_scsi_host;
}

- if (ufshcd_is_clkscaling_supported(hba)) {
- char wq_name[sizeof("ufs_clkscaling_00")];
-
- INIT_WORK(&hba->clk_scaling.suspend_work,
- ufshcd_clk_scaling_suspend_work);
- INIT_WORK(&hba->clk_scaling.resume_work,
- ufshcd_clk_scaling_resume_work);
-
- snprintf(wq_name, sizeof(wq_name), "ufs_clkscaling_%d",
- host->host_no);
- hba->clk_scaling.workq = create_singlethread_workqueue(wq_name);
-
- ufshcd_clkscaling_init_sysfs(hba);
- }
-
/*
* Set the default power management level for runtime and system PM.
* Default power saving mode is to keep UFS link in Hibern8 state
@@ -8169,6 +8183,7 @@ int ufshcd_init(struct ufs_hba *hba, void __iomem *mmio_base, unsigned int irq)
out_remove_scsi_host:
scsi_remove_host(hba->host);
exit_gating:
+ ufshcd_exit_clk_scaling(hba);
ufshcd_exit_clk_gating(hba);
out_disable:
hba->is_irq_enabled = false;
--
2.20.1
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