random: fix possible sleeping allocation from irq context

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>

diff --git a/drivers/char/random.c b/drivers/char/random.c
index b979173..dbfb3e6 100644 (file)
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -820,7 +820,7 @@ static int crng_fast_load(const char *cp, size_t len)
 }
 
 #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;
@@ -841,6 +841,13 @@ 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