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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@gmail.com>,
        Hans Verkuil <hans.verkuil@cisco.com>,
        Mauro Carvalho Chehab <mchehab+samsung@kernel.org>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.9 109/222] media: pci: ivtv: Fix a sleep-in-atomic-context bug in ivtv_yuv_init()
Date:   Fri, 22 Nov 2019 11:27:29 +0100
Message-Id: <20191122100911.152356349@linuxfoundation.org>
In-Reply-To: <20191122100830.874290814@linuxfoundation.org>
References: <20191122100830.874290814@linuxfoundation.org>
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From: Jia-Ju Bai <baijiaju1990@gmail.com>

[ Upstream commit 8d11eb847de7d89c2754988c944d51a4f63e219b ]

The driver may sleep in a interrupt handler.

The function call paths (from bottom to top) in Linux-4.16 are:

[FUNC] kzalloc(GFP_KERNEL)
drivers/media/pci/ivtv/ivtv-yuv.c, 938:
	kzalloc in ivtv_yuv_init
drivers/media/pci/ivtv/ivtv-yuv.c, 960:
	ivtv_yuv_init in ivtv_yuv_next_free
drivers/media/pci/ivtv/ivtv-yuv.c, 1126:
	ivtv_yuv_next_free in ivtv_yuv_setup_stream_frame
drivers/media/pci/ivtv/ivtv-irq.c, 827:
	ivtv_yuv_setup_stream_frame in ivtv_irq_dec_data_req
drivers/media/pci/ivtv/ivtv-irq.c, 1013:
	ivtv_irq_dec_data_req in ivtv_irq_handler

To fix this bug, GFP_KERNEL is replaced with GFP_ATOMIC.

This bug is found by my static analysis tool DSAC.

Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/media/pci/ivtv/ivtv-yuv.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/media/pci/ivtv/ivtv-yuv.c b/drivers/media/pci/ivtv/ivtv-yuv.c
index f7299d3d82449..bcb51e87c72f0 100644
--- a/drivers/media/pci/ivtv/ivtv-yuv.c
+++ b/drivers/media/pci/ivtv/ivtv-yuv.c
@@ -935,7 +935,7 @@ static void ivtv_yuv_init(struct ivtv *itv)
 	}
 
 	/* We need a buffer for blanking when Y plane is offset - non-fatal if we can't get one */
-	yi->blanking_ptr = kzalloc(720 * 16, GFP_KERNEL|__GFP_NOWARN);
+	yi->blanking_ptr = kzalloc(720 * 16, GFP_ATOMIC|__GFP_NOWARN);
 	if (yi->blanking_ptr) {
 		yi->blanking_dmaptr = pci_map_single(itv->pdev, yi->blanking_ptr, 720*16, PCI_DMA_TODEVICE);
 	} else {
-- 
2.20.1