From mboxrd@z Thu Jan  1 00:00:00 1970
From: David Miller <davem@davemloft.net>
Subject: Re: [PATCH] net/nfc: Avoid stalls when nfc_alloc_send_skb()
 returned NULL.
Date: Thu, 19 Jul 2018 02:52:24 +0900 (KST)
Message-ID: <20180719.025224.724580559198605486.davem@davemloft.net>
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From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Date: Wed, 18 Jul 2018 18:57:27 +0900

> syzbot is reporting stalls at nfc_llcp_send_ui_frame() [1]. This is
> because nfc_llcp_send_ui_frame() is retrying the loop without any delay
> when nonblocking nfc_alloc_send_skb() returned NULL.
> 
> Since there is no need to use MSG_DONTWAIT if we retry until
> sock_alloc_send_pskb() succeeds, let's use blocking call.
> Also, in case an unexpected error occurred, let's break the loop
> if blocking nfc_alloc_send_skb() failed.
> 
> [1] https://syzkaller.appspot.com/bug?id=4a131cc571c3733e0eff6bc673f4e36ae48f19c6
> 
> Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
> Reported-by: syzbot <syzbot+d29d18215e477cfbfbdd@syzkaller.appspotmail.com>

Applied and queued up for -stable, thanks.