linux-kernel - [PATCH v6 3/5] kernel/cpu_pm: Fix uninitted local in cpu

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Message-Id: <20200504104917.v6.3.I2d44fc0053d019f239527a4e5829416714b7e299@changeid>
Date:   Mon,  4 May 2020 10:50:17 -0700
From:   Douglas Anderson <dianders@...omium.org>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        rafael.j.wysocki@...el.com, Andy Gross <agross@...nel.org>,
        Bjorn Andersson <bjorn.andersson@...aro.org>
Cc:     evgreen@...omium.org, swboyd@...omium.org, mka@...omium.org,
        mkshah@...eaurora.org, Douglas Anderson <dianders@...omium.org>,
        Alexios Zavras <alexios.zavras@...el.com>,
        Colin Cross <ccross@...roid.com>,
        Kevin Hilman <khilman@...com>,
        Santosh Shilimkar <santosh.shilimkar@...com>,
        Thomas Gleixner <tglx@...utronix.de>,
        linux-kernel@...r.kernel.org
Subject: [PATCH v6 3/5] kernel/cpu_pm: Fix uninitted local in cpu_pm

cpu_pm_notify() is basically a wrapper of notifier_call_chain().
notifier_call_chain() doesn't initialize *nr_calls to 0 before it
starts incrementing it--presumably it's up to the callers to do this.

Unfortunately the callers of cpu_pm_notify() don't init *nr_calls.
This potentially means you could get too many or two few calls to
CPU_PM_ENTER_FAILED or CPU_CLUSTER_PM_ENTER_FAILED depending on the
luck of the stack.

Let's fix this.

Fixes: ab10023e0088 ("cpu_pm: Add cpu power management notifiers")
Signed-off-by: Douglas Anderson <dianders@...omium.org>
Cc: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Reviewed-by: Stephen Boyd <swboyd@...omium.org>
---
This seems to be an ownerless file.  I'm hoping this patch can just go
through the Qualcomm tree.  It would be nice if we could get an Ack
from Rafael or Greg KH though.

Changes in v6: None
Changes in v5: None
Changes in v4: None
Changes in v3: None
Changes in v2:
- ("Fix uninitted local in cpu_pm") new for v2.

 kernel/cpu_pm.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/cpu_pm.c b/kernel/cpu_pm.c
index cbca6879ab7d..44a259338e33 100644
--- a/kernel/cpu_pm.c
+++ b/kernel/cpu_pm.c
@@ -80,7 +80,7 @@ EXPORT_SYMBOL_GPL(cpu_pm_unregister_notifier);
  */
 int cpu_pm_enter(void)
 {
-	int nr_calls;
+	int nr_calls = 0;
 	int ret = 0;
 
 	ret = cpu_pm_notify(CPU_PM_ENTER, -1, &nr_calls);
@@ -131,7 +131,7 @@ EXPORT_SYMBOL_GPL(cpu_pm_exit);
  */
 int cpu_cluster_pm_enter(void)
 {
-	int nr_calls;
+	int nr_calls = 0;
 	int ret = 0;
 
 	ret = cpu_pm_notify(CPU_CLUSTER_PM_ENTER, -1, &nr_calls);
-- 
2.26.2.526.g744177e7f7-goog