3.16.7-ckt1 -stable review patch. If anyone has any objections, please let me know.
------------------
From: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
commit a968bed78b549b4c61d4a46e59161fc1f60f96a6 upstream.
Unlike the clocks management code for runtime PM, the code used for
system suspend does not check the pm_clock_entry.status field.
If pm_clk_acquire() failed, ce->status will be PCE_STATUS_ERROR, and
ce->clk will be a negative error code (e.g. 0xfffffffe = -2 = -ENOENT).
Depending on the clock implementation, suspend or resume may crash with:
Unable to handle kernel NULL pointer dereference at virtual address 00000026
(CCF clk_disable() has an IS_ERR_OR_NULL() check, while CCF clk_enable()
only has a NULL check; pre-CCF implementations may behave differently)
While just checking for PCE_STATUS_ERROR would be sufficient, it doesn't
hurt to use the same state machine as is done for runtime PM, as this
makes the two versions more similar, and eligible for a future
consolidation.
Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Signed-off-by: Luis Henriques <luis.henriques@xxxxxxxxxxxxx>
---
drivers/base/power/clock_ops.c | 19 +++++++++++++++----
1 file changed, 15 insertions(+), 4 deletions(-)
diff --git a/drivers/base/power/clock_ops.c b/drivers/base/power/clock_ops.c
index b99e6c06ee67..78369305e069 100644
--- a/drivers/base/power/clock_ops.c
+++ b/drivers/base/power/clock_ops.c
@@ -368,8 +368,13 @@ int pm_clk_suspend(struct device *dev)
spin_lock_irqsave(&psd->lock, flags);
- list_for_each_entry_reverse(ce, &psd->clock_list, node)
- clk_disable(ce->clk);
+ list_for_each_entry_reverse(ce, &psd->clock_list, node) {
+ if (ce->status < PCE_STATUS_ERROR) {
+ if (ce->status == PCE_STATUS_ENABLED)
+ clk_disable(ce->clk);
+ ce->status = PCE_STATUS_ACQUIRED;
+ }
+ }
spin_unlock_irqrestore(&psd->lock, flags);
@@ -385,6 +390,7 @@ int pm_clk_resume(struct device *dev)
struct pm_subsys_data *psd = dev_to_psd(dev);
struct pm_clock_entry *ce;
unsigned long flags;
+ int ret;
dev_dbg(dev, "%s()\n", __func__);
@@ -394,8 +400,13 @@ int pm_clk_resume(struct device *dev)
spin_lock_irqsave(&psd->lock, flags);
- list_for_each_entry(ce, &psd->clock_list, node)
- __pm_clk_enable(dev, ce->clk);
+ list_for_each_entry(ce, &psd->clock_list, node) {
+ if (ce->status < PCE_STATUS_ERROR) {
+ ret = __pm_clk_enable(dev, ce->clk);
+ if (!ret)
+ ce->status = PCE_STATUS_ENABLED;
+ }
+ }
spin_unlock_irqrestore(&psd->lock, flags);
--
2.1.0
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