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Subject[PATCH] power: avoid calling cancel_delayed_work_sync() during early boot
of_clk_init() ends up calling into pm_qos_update_request() very early
during boot where irq is expected to stay disabled.
pm_qos_update_request() uses cancel_delayed_work_sync() which
correctly assumes that irq is enabled on invocation and
unconditionally disables and re-enables it.

Gate cancel_delayed_work_sync() invocation with kevented_up() to avoid
enabling irq unexpectedly during early boot.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-and-tested-by: Qiao Zhou <qiaozhou@asrmicro.com>
Link: http://lkml.kernel.org/r/d2501c4c-8e7b-bea3-1b01-000b36b5dfe9@asrmicro.com
---

Rafael, can you please route this patch?

Thanks.

kernel/power/qos.c | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/kernel/power/qos.c b/kernel/power/qos.c
index 97b0df7..168ff44 100644
--- a/kernel/power/qos.c
+++ b/kernel/power/qos.c
@@ -482,7 +482,16 @@ void pm_qos_update_request(struct pm_qos_request *req,
return;
}

- cancel_delayed_work_sync(&req->work);
+ /*
+ * This function may be called very early during boot, for example,
+ * from of_clk_init(), where irq needs to stay disabled.
+ * cancel_delayed_work_sync() assumes that irq is enabled on
+ * invocation and re-enables it on return. Avoid calling it until
+ * workqueue is initialized.
+ */
+ if (keventd_up())
+ cancel_delayed_work_sync(&req->work);
+
__pm_qos_update_request(req, new_value);
}
EXPORT_SYMBOL_GPL(pm_qos_update_request);
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