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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Arnd Bergmann <arnd@arndb.de>,
	Nathan Chancellor <natechancellor@gmail.com>,
	Lad Prabhakar <prabhakar.csengg@gmail.com>,
	Hans Verkuil <hverkuil-cisco@xs4all.nl>,
	Mauro Carvalho Chehab <mchehab+samsung@kernel.org>,
	Sasha Levin <sashal@kernel.org>,
	linux-media@vger.kernel.org, clang-built-linux@googlegroups.com
Subject: [PATCH AUTOSEL 4.4 066/174] media: davinci-isif: avoid uninitialized variable use
Date: Thu, 16 Jan 2020 12:41:03 -0500
Message-ID: <20200116174251.24326-66-sashal@kernel.org> (raw)
In-Reply-To: <20200116174251.24326-1-sashal@kernel.org>

From: Arnd Bergmann <arnd@arndb.de>

[ Upstream commit 0e633f97162c1c74c68e2eb20bbd9259dce87cd9 ]

clang warns about a possible variable use that gcc never
complained about:

drivers/media/platform/davinci/isif.c:982:32: error: variable 'frame_size' is uninitialized when used here
      [-Werror,-Wuninitialized]
                dm365_vpss_set_pg_frame_size(frame_size);
                                             ^~~~~~~~~~
drivers/media/platform/davinci/isif.c:887:2: note: variable 'frame_size' is declared here
        struct vpss_pg_frame_size frame_size;
        ^
1 error generated.

There is no initialization for this variable at all, and there
has never been one in the mainline kernel, so we really should
not put that stack data into an mmio register.

On the other hand, I suspect that gcc checks the condition
more closely and notices that the global
isif_cfg.bayer.config_params.test_pat_gen flag is initialized
to zero and never written to from any code path, so anything
depending on it can be eliminated.

To shut up the clang warning, just remove the dead code manually,
it has probably never been used because any attempt to do so
would have resulted in undefined behavior.

Fixes: 63e3ab142fa3 ("V4L/DVB: V4L - vpfe capture - source for ISIF driver on DM365")

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Acked-by: Lad Prabhakar <prabhakar.csengg@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/media/platform/davinci/isif.c | 9 ---------
 1 file changed, 9 deletions(-)

diff --git a/drivers/media/platform/davinci/isif.c b/drivers/media/platform/davinci/isif.c
index 78e37cf3470f..b51b875c5a61 100644
--- a/drivers/media/platform/davinci/isif.c
+++ b/drivers/media/platform/davinci/isif.c
@@ -890,9 +890,7 @@ static int isif_set_hw_if_params(struct vpfe_hw_if_param *params)
 static int isif_config_ycbcr(void)
 {
 	struct isif_ycbcr_config *params = &isif_cfg.ycbcr;
-	struct vpss_pg_frame_size frame_size;
 	u32 modeset = 0, ccdcfg = 0;
-	struct vpss_sync_pol sync;
 
 	dev_dbg(isif_cfg.dev, "\nStarting isif_config_ycbcr...");
 
@@ -980,13 +978,6 @@ static int isif_config_ycbcr(void)
 		/* two fields are interleaved in memory */
 		regw(0x00000249, SDOFST);
 
-	/* Setup test pattern if enabled */
-	if (isif_cfg.bayer.config_params.test_pat_gen) {
-		sync.ccdpg_hdpol = params->hd_pol;
-		sync.ccdpg_vdpol = params->vd_pol;
-		dm365_vpss_set_sync_pol(sync);
-		dm365_vpss_set_pg_frame_size(frame_size);
-	}
 	return 0;
 }
 
-- 
2.20.1


  parent reply index

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20200116174251.24326-1-sashal@kernel.org>
2020-01-16 17:40 ` [PATCH AUTOSEL 4.4 032/174] media: s5p-jpeg: Correct step and max values for V4L2_CID_JPEG_RESTART_INTERVAL Sasha Levin
2020-01-16 17:40 ` [PATCH AUTOSEL 4.4 059/174] media: ivtv: update *pos correctly in ivtv_read_pos() Sasha Levin
2020-01-16 17:40 ` [PATCH AUTOSEL 4.4 060/174] media: cx18: update *pos correctly in cx18_read_pos() Sasha Levin
2020-01-16 17:40 ` [PATCH AUTOSEL 4.4 061/174] media: wl128x: Fix an error code in fm_download_firmware() Sasha Levin
2020-01-16 17:40 ` [PATCH AUTOSEL 4.4 062/174] media: cx23885: check allocation return Sasha Levin
2020-01-16 17:41 ` Sasha Levin [this message]
2020-01-16 17:41 ` [PATCH AUTOSEL 4.4 078/174] media: ov2659: fix unbalanced mutex_lock/unlock Sasha Levin
2020-01-16 17:41 ` [PATCH AUTOSEL 4.4 086/174] media: omap_vout: potential buffer overflow in vidioc_dqbuf() Sasha Levin
2020-01-16 17:41 ` [PATCH AUTOSEL 4.4 087/174] media: davinci/vpbe: array underflow in vpbe_enum_outputs() Sasha Levin
2020-01-16 17:41 ` [PATCH AUTOSEL 4.4 099/174] media: vivid: fix incorrect assignment operation when setting video mode Sasha Levin
2020-01-16 17:42 ` [PATCH AUTOSEL 4.4 152/174] media: ov6650: Fix incorrect use of JPEG colorspace Sasha Levin
2020-01-16 17:42 ` [PATCH AUTOSEL 4.4 153/174] media: ov6650: Fix some format attributes not under control Sasha Levin
2020-01-16 17:42 ` [PATCH AUTOSEL 4.4 154/174] media: ov6650: Fix .get_fmt() V4L2_SUBDEV_FORMAT_TRY support Sasha Levin
2020-01-16 17:42 ` [PATCH AUTOSEL 4.4 161/174] media: exynos4-is: Fix recursive locking in isp_video_release() Sasha Levin

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