3.16.7-ckt1 -stable review patch. If anyone has any objections, please let me know.
------------------ From: Geert Uytterhoeven <[email protected]> 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 <[email protected]> Signed-off-by: Rafael J. Wysocki <[email protected]> Signed-off-by: Luis Henriques <[email protected]> --- 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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
