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

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Message-Id: <20220623164344.609507273@linuxfoundation.org>
Date:   Thu, 23 Jun 2022 18:40:12 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        Tetsuo Handa <penguin-kernel@...ove.SAKURA.ne.jp>,
        syzbot+9de458f6a5e713ee8c1a@...kaller.appspotmail.com,
        Theodore Tso <tytso@....edu>
Subject: [PATCH 4.9 019/264] random: fix possible sleeping allocation from irq context

From: Theodore Ts'o <tytso@....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@...ove.SAKURA.ne.jp>
Reported-by: syzbot+9de458f6a5e713ee8c1a@...kaller.appspotmail.com
Fixes: 8ef35c866f8862df ("random: set up the NUMA crng instances...")
Cc: stable@...r.kernel.org
Signed-off-by: Theodore Ts'o <tytso@....edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.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