From 59c39840f5abf4a71e1810a8da71aaccd6c17d26 Mon Sep 17 00:00:00 2001
From: Prasad Sodagudi <psodagud@codeaurora.org>
Date: Sun, 24 Mar 2019 07:57:04 -0700
Subject: [PATCH] genirq: Prevent use-after-free and work list corruption
Git-commit: 59c39840f5abf4a71e1810a8da71aaccd6c17d26
Patch-mainline: v5.2-rc1
References: bsc#1051510

When irq_set_affinity_notifier() replaces the notifier, then the
reference count on the old notifier is dropped which causes it to be
freed. But nothing ensures that the old notifier is not longer queued
in the work list. If it is queued this results in a use after free and
possibly in work list corruption.

Ensure that the work is canceled before the reference is dropped.

Signed-off-by: Prasad Sodagudi <psodagud@codeaurora.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: marc.zyngier@arm.com
Link: https://lkml.kernel.org/r/1553439424-6529-1-git-send-email-psodagud@codeaurora.org
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 kernel/irq/manage.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 1401afa0d58a..53a081392115 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -357,8 +357,10 @@ irq_set_affinity_notifier(unsigned int irq, struct irq_affinity_notify *notify)
 	desc->affinity_notify = notify;
 	raw_spin_unlock_irqrestore(&desc->lock, flags);
 
-	if (old_notify)
+	if (old_notify) {
+		cancel_work_sync(&old_notify->work);
 		kref_put(&old_notify->kref, old_notify->release);
+	}
 
 	return 0;
 }
-- 
2.16.4