From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 11A55129ED2; Mon, 18 Dec 2023 13:52:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="qNl9oJXm" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 46790C433C7; Mon, 18 Dec 2023 13:52:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1702907552; bh=f++bKAGfdlg6MvPx4wQDUz8N5SEtNEvvBHCKgQYgFJY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=qNl9oJXm0RR7iQ+CK/6mrLLU6hM6JFJDLtHofOpvHJLGATTI3hLTPQ3u/JH5p1a02 TiLQ23LbfD+pk5y4u42iax6im1zWlDmj58drGMxkdRUYdA/xvmQe5g1l1UxZ4KrF9z q7nm1Fg7SGU0NtFUz5vuOJ3r1IIZxelcqcv/3vz4= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Chengfeng Ye , "David S. Miller" , Sasha Levin Subject: [PATCH 4.14 04/26] atm: solos-pci: Fix potential deadlock on &cli_queue_lock Date: Mon, 18 Dec 2023 14:51:06 +0100 Message-ID: <20231218135040.817352474@linuxfoundation.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20231218135040.665690087@linuxfoundation.org> References: <20231218135040.665690087@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Chengfeng Ye [ Upstream commit d5dba32b8f6cb39be708b726044ba30dbc088b30 ] As &card->cli_queue_lock is acquired under softirq context along the following call chain from solos_bh(), other acquisition of the same lock inside process context should disable at least bh to avoid double lock. console_show() --> spin_lock(&card->cli_queue_lock) --> solos_bh() --> spin_lock(&card->cli_queue_lock) This flaw was found by an experimental static analysis tool I am developing for irq-related deadlock. To prevent the potential deadlock, the patch uses spin_lock_bh() on the card->cli_queue_lock under process context code consistently to prevent the possible deadlock scenario. Fixes: 9c54004ea717 ("atm: Driver for Solos PCI ADSL2+ card.") Signed-off-by: Chengfeng Ye Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- drivers/atm/solos-pci.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/atm/solos-pci.c b/drivers/atm/solos-pci.c index 0df1a1c80b001..3a115c7f224fb 100644 --- a/drivers/atm/solos-pci.c +++ b/drivers/atm/solos-pci.c @@ -458,9 +458,9 @@ static ssize_t console_show(struct device *dev, struct device_attribute *attr, struct sk_buff *skb; unsigned int len; - spin_lock(&card->cli_queue_lock); + spin_lock_bh(&card->cli_queue_lock); skb = skb_dequeue(&card->cli_queue[SOLOS_CHAN(atmdev)]); - spin_unlock(&card->cli_queue_lock); + spin_unlock_bh(&card->cli_queue_lock); if(skb == NULL) return sprintf(buf, "No data.\n"); -- 2.43.0