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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Jia-Ju Bai <baijiaju1990@163.com>,
        "David S. Miller" <davem@davemloft.net>,
        Sasha Levin <alexander.levin@microsoft.com>
Subject: [PATCH 4.4 112/190] mISDN: Fix a sleep-in-atomic bug
Date:   Wed, 11 Apr 2018 20:35:58 +0200
Message-Id: <20180411183557.570399140@linuxfoundation.org>
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4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Jia-Ju Bai <baijiaju1990@163.com>


[ Upstream commit 93818da5eed63fbc17b64080406ea53b86b23309 ]

The driver may sleep under a read spin lock, and the function call path is:
send_socklist (acquire the lock by read_lock)
  skb_copy(GFP_KERNEL) --> may sleep

To fix it, the "GFP_KERNEL" is replaced with "GFP_ATOMIC".

Signed-off-by: Jia-Ju Bai <baijiaju1990@163.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/isdn/mISDN/stack.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/isdn/mISDN/stack.c
+++ b/drivers/isdn/mISDN/stack.c
@@ -72,7 +72,7 @@ send_socklist(struct mISDN_sock_list *sl
 		if (sk->sk_state != MISDN_BOUND)
 			continue;
 		if (!cskb)
-			cskb = skb_copy(skb, GFP_KERNEL);
+			cskb = skb_copy(skb, GFP_ATOMIC);
 		if (!cskb) {
 			printk(KERN_WARNING "%s no skb\n", __func__);
 			break;