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authorEdward Cree <ecree@solarflare.com>2020-03-13 20:33:07 +0000
committerThomas Gleixner <tglx@linutronix.de>2020-03-21 17:32:46 +0100
commitdf81dfcfd6991d547653d46c051bac195cd182c1 (patch)
tree5a6ed7725d8a3b3d1fbe73e33265b3a00ee1217b
parent5ad0ec0b86525d0c5d3d250d3cfad7f183b00cfa (diff)
downloadlinux-sh-df81dfcfd6991d547653d46c051bac195cd182c1.tar.gz
genirq: Fix reference leaks on irq affinity notifiers
The handling of notify->work did not properly maintain notify->kref in two cases: 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 <ecree@solarflare.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Ben Hutchings <ben@decadent.org.uk> Link: https://lkml.kernel.org/r/24f5983f-2ab5-e83a-44ee-a45b5f9300f5@solarflare.com
-rw-r--r--kernel/irq/manage.c11
1 files changed, 9 insertions, 2 deletions
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 7eee98c38f25..fe40c658f86f 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -323,7 +323,11 @@ int irq_set_affinity_locked(struct irq_data *data, const struct cpumask *mask,
if (desc->affinity_notify) {
kref_get(&desc->affinity_notify->kref);
- 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);
@@ -423,7 +427,10 @@ 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);
}