[tip:irq/core] genirq: Fix null pointer reference in irq_set_affinity_hint()

From: tip-bot for Jesse Brandeburg
Date: Mon Feb 09 2015 - 12:51:48 EST

Commit-ID: 4fe7ffb7e17ca6ad9173b8de35f260c9c8fc2f79
Gitweb: http://git.kernel.org/tip/4fe7ffb7e17ca6ad9173b8de35f260c9c8fc2f79
Author: Jesse Brandeburg <jesse.brandeburg@xxxxxxxxx>
AuthorDate: Wed, 28 Jan 2015 10:57:39 -0800
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Mon, 9 Feb 2015 18:47:42 +0100

genirq: Fix null pointer reference in irq_set_affinity_hint()

The recent set_affinity commit by me introduced some null
pointer dereferences on driver unload, because some drivers
call this function with a NULL argument. This fixes the issue
by just checking for null before setting the affinity mask.

Fixes: e2e64a932556 ("genirq: Set initial affinity in irq_set_affinity_hint()")
Reported-by: Yinghai Lu <yinghai@xxxxxxxxxx>
Signed-off-by: Jesse Brandeburg <jesse.brandeburg@xxxxxxxxx>
CC: netdev@xxxxxxxxxxxxxxx
Link: http://lkml.kernel.org/r/20150128185739.9689.84588.stgit@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
kernel/irq/manage.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index f038e58..196a06f 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -244,7 +244,8 @@ int irq_set_affinity_hint(unsigned int irq, const struct cpumask *m)
desc->affinity_hint = m;
irq_put_desc_unlock(desc, flags);
/* set the initial affinity to prevent every interrupt being on CPU0 */
- __irq_set_affinity(irq, m, false);
+ if (m)
+ __irq_set_affinity(irq, m, false);
return 0;
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