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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, Michal Nazarewicz <mina86@mina86.com>,
        Lars-Peter Clausen <lars@metafoo.de>,
        Alexandru Ardelean <alexandru.ardelean@analog.com>,
        Felipe Balbi <balbi@kernel.org>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.4 41/72] usb: gadget: ffs: ffs_aio_cancel(): Save/restore IRQ flags
Date:   Tue, 10 Mar 2020 13:38:54 +0100
Message-Id: <20200310123611.686906801@linuxfoundation.org>
In-Reply-To: <20200310123601.053680753@linuxfoundation.org>
References: <20200310123601.053680753@linuxfoundation.org>
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From: Lars-Peter Clausen <lars@metafoo.de>

[ Upstream commit 43d565727a3a6fd24e37c7c2116475106af71806 ]

ffs_aio_cancel() can be called from both interrupt and thread context. Make
sure that the current IRQ state is saved and restored by using
spin_{un,}lock_irq{save,restore}().

Otherwise undefined behavior might occur.

Acked-by: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/usb/gadget/function/f_fs.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c
index 4cb1355271ec4..9536c409a90d5 100644
--- a/drivers/usb/gadget/function/f_fs.c
+++ b/drivers/usb/gadget/function/f_fs.c
@@ -888,18 +888,19 @@ static int ffs_aio_cancel(struct kiocb *kiocb)
 {
 	struct ffs_io_data *io_data = kiocb->private;
 	struct ffs_epfile *epfile = kiocb->ki_filp->private_data;
+	unsigned long flags;
 	int value;
 
 	ENTER();
 
-	spin_lock_irq(&epfile->ffs->eps_lock);
+	spin_lock_irqsave(&epfile->ffs->eps_lock, flags);
 
 	if (likely(io_data && io_data->ep && io_data->req))
 		value = usb_ep_dequeue(io_data->ep, io_data->req);
 	else
 		value = -EINVAL;
 
-	spin_unlock_irq(&epfile->ffs->eps_lock);
+	spin_unlock_irqrestore(&epfile->ffs->eps_lock, flags);
 
 	return value;
 }
-- 
2.20.1