From: Eli Cohen elic@nvidia.com
[ Upstream commit 4e0473f1060aa49621d40a113afde24818101d37 ]
When calling irq_set_affinity_notifier() with NULL at the notify argument, it will cause freeing of the glue pointer in the corresponding array entry but will leave the pointer in the array. A subsequent call to free_irq_cpu_rmap() will try to free this entry again leading to possible use after free.
Fix that by setting NULL to the array entry and checking that we have non-zero at the array entry when iterating over the array in free_irq_cpu_rmap().
The current code does not suffer from this since there are no cases where irq_set_affinity_notifier(irq, NULL) (note the NULL passed for the notify arg) is called, followed by a call to free_irq_cpu_rmap() so we don't hit and issue. Subsequent patches in this series excersize this flow, hence the required fix.
Cc: Thomas Gleixner tglx@linutronix.de Signed-off-by: Eli Cohen elic@nvidia.com Signed-off-by: Saeed Mahameed saeedm@nvidia.com Reviewed-by: Jacob Keller jacob.e.keller@intel.com Signed-off-by: Sasha Levin sashal@kernel.org --- lib/cpu_rmap.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/lib/cpu_rmap.c b/lib/cpu_rmap.c index 075f3788bbe4d..920403fa5b0de 100644 --- a/lib/cpu_rmap.c +++ b/lib/cpu_rmap.c @@ -232,7 +232,8 @@ void free_irq_cpu_rmap(struct cpu_rmap *rmap)
for (index = 0; index < rmap->used; index++) { glue = rmap->obj[index]; - irq_set_affinity_notifier(glue->notify.irq, NULL); + if (glue) + irq_set_affinity_notifier(glue->notify.irq, NULL); }
cpu_rmap_put(rmap); @@ -268,6 +269,7 @@ static void irq_cpu_rmap_release(struct kref *ref) container_of(ref, struct irq_glue, notify.kref);
cpu_rmap_put(glue->rmap); + glue->rmap->obj[glue->index] = NULL; kfree(glue); }
@@ -297,6 +299,7 @@ int irq_cpu_rmap_add(struct cpu_rmap *rmap, int irq) rc = irq_set_affinity_notifier(irq, &glue->notify); if (rc) { cpu_rmap_put(glue->rmap); + rmap->obj[glue->index] = NULL; kfree(glue); } return rc;