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Subject[PATCH] PM: Prevent waiting forever on asynchronous suspend after abort
Date
From: Mandeep Singh Baines <msb@chromium.org>

__device_suspend() must always send a completion. Otherwise, parent
devices will wait forever.

Commit 1e2ef05b, "PM: Limit race conditions between runtime PM and
system sleep (v2)", introduced a regression by short-circuiting the
complete_all() for certain error cases.

This patch fixes the bug by always signalling a completion.

Addresses http://crosbug.com/31972

Tested by injecting an abort.

Signed-off-by: Mandeep Singh Baines <msb@chromium.org>
Cc: Rafael J. Wysocki <rjw@sisk.pl>
Cc: linux-pm@vger.kernel.org
Cc: stable@kernel.org
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Len Brown <len.brown@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Kevin Hilman <khilman@ti.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Colin Cross <ccross@android.com>
Cc: Sameer Nanda <snanda@chromium.org>
Cc: Olof Johansson <olofj@chromium.org>
---
drivers/base/power/main.c | 6 ++++--
1 files changed, 4 insertions(+), 2 deletions(-)
diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
index e0fb5b0..9cb845e 100644
--- a/drivers/base/power/main.c
+++ b/drivers/base/power/main.c
@@ -1031,7 +1031,7 @@ static int __device_suspend(struct device *dev, pm_message_t state, bool async)
dpm_wait_for_children(dev, async);

if (async_error)
- return 0;
+ goto Complete;

pm_runtime_get_noresume(dev);
if (pm_runtime_barrier(dev) && device_may_wakeup(dev))
@@ -1040,7 +1040,7 @@ static int __device_suspend(struct device *dev, pm_message_t state, bool async)
if (pm_wakeup_pending()) {
pm_runtime_put_sync(dev);
async_error = -EBUSY;
- return 0;
+ goto Complete;
}

device_lock(dev);
@@ -1097,6 +1097,8 @@ static int __device_suspend(struct device *dev, pm_message_t state, bool async)
}

device_unlock(dev);
+
+ Complete:
complete_all(&dev->power.completion);

if (error) {
--
1.7.3.4


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