Subject: fix sighand use after free
__lock_task_sighand carefully takes the rcu_read_lock, gets
tsk->sighand with rcu_dereference, and verifies that the task
is still using the sighand_struct after taking the spinlock.
This works much better if the sighand struct is actually rcu
freed.
Signed-off-by: Rik van Riel <r...@redhat.com>
---
kernel/fork.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/fork.c b/kernel/fork.c
index 1380d8a..754a7c6 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1017,7 +1017,7 @@ void __cleanup_sighand(struct sighand_struct *sighand)
{
if (atomic_dec_and_test(&sighand->count)) {
signalfd_cleanup(sighand);
- kmem_cache_free(sighand_cachep, sighand);
+ rcu_free(sighand_cachep, sighand);
}
}
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