blob: d23e19b8b81083d4f149b2c750e8a123fea04f12 [file] [log] [blame]
From 656fb24fdeb4b28d7a82e803d37272369654a604 Mon Sep 17 00:00:00 2001
From: Edward Cree <>
Date: Fri, 13 Mar 2020 20:33:07 +0000
Subject: [PATCH] genirq: Fix reference leaks on irq affinity notifiers
commit df81dfcfd6991d547653d46c051bac195cd182c1 upstream.
The handling of notify->work did not properly maintain notify->kref in two
1) where the work was already scheduled, another irq_set_affinity_locked()
would get the ref and (no-op-ly) schedule the work. Thus when
irq_affinity_notify() ran, it would drop the original ref but not the
additional one.
2) when cancelling the (old) work in irq_set_affinity_notifier(), if there
was outstanding work a ref had been got for it but was never put.
Fix both by checking the return values of the work handling functions
(schedule_work() for (1) and cancel_work_sync() for (2)) and put the
extra ref if the return value indicates preexisting work.
Fixes: cd7eab44e994 ("genirq: Add IRQ affinity notifiers")
Fixes: 59c39840f5ab ("genirq: Prevent use-after-free and work list corruption")
Signed-off-by: Edward Cree <>
Signed-off-by: Thomas Gleixner <>
Acked-by: Ben Hutchings <>
Signed-off-by: Paul Gortmaker <>
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 3ef3afa49380..e88faff5bea5 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -284,7 +284,11 @@ int irq_set_affinity_locked(struct irq_data *data, const struct cpumask *mask,
if (desc->affinity_notify) {
- schedule_work(&desc->affinity_notify->work);
+ if (!schedule_work(&desc->affinity_notify->work)) {
+ /* Work was already scheduled, drop our extra ref */
+ kref_put(&desc->affinity_notify->kref,
+ desc->affinity_notify->release);
+ }
irqd_set(data, IRQD_AFFINITY_SET);
@@ -384,7 +388,10 @@ irq_set_affinity_notifier(unsigned int irq, struct irq_affinity_notify *notify)
raw_spin_unlock_irqrestore(&desc->lock, flags);
if (old_notify) {
- cancel_work_sync(&old_notify->work);
+ if (cancel_work_sync(&old_notify->work)) {
+ /* Pending work had a ref, put that one too */
+ kref_put(&old_notify->kref, old_notify->release);
+ }
kref_put(&old_notify->kref, old_notify->release);