[PATCH 4.9 019/264] random: fix possible sleeping allocation from irq context

Greg Kroah-Hartman
2022-06-23T16:47:15Z

From: Theodore Ts'o <tytso@mit.edu>

commit 6c1e851c4edc13a43adb3ea4044e3fc8f43ccf7d upstream.

We can do a sleeping allocation from an irq context when CONFIG_NUMA
is enabled. Fix this by initializing the NUMA crng instances in a
workqueue.

Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reported-by: syzbot+9de458f6a5e713ee8c1a@syzkaller.appspotmail.com
Fixes: 8ef35c866f8862df ("random: set up the NUMA crng instances...")
Cc: stable@vger.kernel.org
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/char/random.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)

--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -800,7 +800,7 @@ static void crng_initialize(struct crng_
}

#ifdef CONFIG_NUMA
-static void numa_crng_init(void)
+static void do_numa_crng_init(struct work_struct *work)
{
int i;
struct crng_state *crng;
@@ -821,6 +821,13 @@ static void numa_crng_init(void)
kfree(pool);
}
}
+
+static DECLARE_WORK(numa_crng_init_work, do_numa_crng_init);
+
+static void numa_crng_init(void)
+{
+ schedule_work(&numa_crng_init_work);
+}
#else
static void numa_crng_init(void) {}
#endif