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author | Geert Uytterhoeven <geert+renesas@glider.be> | 2014-10-01 18:38:17 (GMT) |
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committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2014-10-03 13:51:39 (GMT) |
commit | a968bed78b549b4c61d4a46e59161fc1f60f96a6 (patch) | |
tree | 22f14101a8807bd8cbf80b9c52b689f498abe12c /drivers/base | |
parent | fe82dcec644244676d55a1384c958d5f67979adb (diff) | |
download | linux-a968bed78b549b4c61d4a46e59161fc1f60f96a6.tar.xz |
PM / clk: Fix crash in clocks management code if !CONFIG_PM_RUNTIME
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@glider.be>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/base')
-rw-r--r-- | drivers/base/power/clock_ops.c | 19 |
1 files changed, 15 insertions, 4 deletions
diff --git a/drivers/base/power/clock_ops.c b/drivers/base/power/clock_ops.c index b99e6c0..7836930 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); |