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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Jia-Ju Bai <baijiaju1990@gmail.com>,
	Felipe Balbi <felipe.balbi@linux.intel.com>,
	Sasha Levin <sashal@kernel.org>,
	linux-usb@vger.kernel.org
Subject: [PATCH AUTOSEL 4.19 034/209] usb: gadget: udc: fotg210-udc: Fix a sleep-in-atomic-context bug in fotg210_get_status()
Date: Tue, 12 Nov 2019 20:47:30 -0500	[thread overview]
Message-ID: <20191113015025.9685-34-sashal@kernel.org> (raw)
In-Reply-To: <20191113015025.9685-1-sashal@kernel.org>

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

[ Upstream commit 2337a77c1cc86bc4e504ecf3799f947659c86026 ]

The driver may sleep in an interrupt handler.
The function call path (from bottom to top) in Linux-4.17 is:

[FUNC] fotg210_ep_queue(GFP_KERNEL)
drivers/usb/gadget/udc/fotg210-udc.c, 744:
	fotg210_ep_queue in fotg210_get_status
drivers/usb/gadget/udc/fotg210-udc.c, 768:
	fotg210_get_status in fotg210_setup_packet
drivers/usb/gadget/udc/fotg210-udc.c, 949:
	fotg210_setup_packet in fotg210_irq (interrupt handler)

To fix this bug, GFP_KERNEL is replaced with GFP_ATOMIC.
If possible, spin_unlock() and spin_lock() around fotg210_ep_queue()
can be also removed.

This bug is found by my static analysis tool DSAC.

Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/usb/gadget/udc/fotg210-udc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/usb/gadget/udc/fotg210-udc.c b/drivers/usb/gadget/udc/fotg210-udc.c
index 587c5037ff079..bc6abaea907d8 100644
--- a/drivers/usb/gadget/udc/fotg210-udc.c
+++ b/drivers/usb/gadget/udc/fotg210-udc.c
@@ -741,7 +741,7 @@ static void fotg210_get_status(struct fotg210_udc *fotg210,
 	fotg210->ep0_req->length = 2;
 
 	spin_unlock(&fotg210->lock);
-	fotg210_ep_queue(fotg210->gadget.ep0, fotg210->ep0_req, GFP_KERNEL);
+	fotg210_ep_queue(fotg210->gadget.ep0, fotg210->ep0_req, GFP_ATOMIC);
 	spin_lock(&fotg210->lock);
 }
 
-- 
2.20.1


       reply	other threads:[~2019-11-13  2:26 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20191113015025.9685-1-sashal@kernel.org>
2019-11-13  1:47 ` Sasha Levin [this message]
2019-11-13  1:47 ` [PATCH AUTOSEL 4.19 035/209] usb: dwc3: gadget: Check ENBLSLPM before sending ep command Sasha Levin
2019-11-13  1:48 ` [PATCH AUTOSEL 4.19 096/209] USB: serial: cypress_m8: fix interrupt-out transfer length Sasha Levin
2019-11-13  1:48 ` [PATCH AUTOSEL 4.19 097/209] usb: dwc2: disable power_down on rockchip devices Sasha Levin

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