| Message ID | 20180122103714.GA25044@mwanda (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 01/22/2018 11:37 AM, Dan Carpenter wrote: > The while loop is a post op, "while (i-- >= 0)" so the last iteration > will read camif_mbus_formats[-1] and then the loop will exit with "i" > set to -2 and so we do: "mf->code = camif_mbus_formats[-2];". > > I've changed it to a pre-op, I've added a check to ensure we found the > right format and I've removed the "mf->code = camif_mbus_formats[i];" > because that is a no-op anyway. > > Fixes: babde1c243b2 ("[media] V4L: Add driver for S3C24XX/S3C64XX SoC series camera interface") > Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> > > diff --git a/drivers/media/platform/s3c-camif/camif-capture.c b/drivers/media/platform/s3c-camif/camif-capture.c > index 437395a61065..012f4b389c55 100644 > --- a/drivers/media/platform/s3c-camif/camif-capture.c > +++ b/drivers/media/platform/s3c-camif/camif-capture.c > @@ -1261,11 +1261,11 @@ static void __camif_subdev_try_format(struct camif_dev *camif, > /* FIXME: constraints against codec or preview path ? */ > pix_lim = &variant->vp_pix_limits[VP_CODEC]; > > - while (i-- >= 0) > + while (--i >= 0) > if (camif_mbus_formats[i] == mf->code) > break; > - > - mf->code = camif_mbus_formats[i]; > + if (i < 0) > + return; Thanks for the patch Dan. mf->width needs to be aligned by this try_format function so we shouldn't return here. Also it needs to be ensured mf->code is set to one of the supported values when this function returns. Sorry, the current code really doesn't give a clue what was intended. There is already queued a patch from Arnd [1] addressing the issues you have found. > if (pad == CAMIF_SD_PAD_SINK) { > v4l_bound_align_image(&mf->width, 8, CAMIF_MAX_PIX_WIDTH, > [1] https://patchwork.linuxtv.org/patch/46508 -- Regards, Sylwester
On Mon, Jan 22, 2018 at 09:50:04PM +0100, Sylwester Nawrocki wrote: > On 01/22/2018 11:37 AM, Dan Carpenter wrote: > > --- a/drivers/media/platform/s3c-camif/camif-capture.c > > +++ b/drivers/media/platform/s3c-camif/camif-capture.c > > @@ -1261,11 +1261,11 @@ static void __camif_subdev_try_format(struct camif_dev *camif, > > /* FIXME: constraints against codec or preview path ? */ > > pix_lim = &variant->vp_pix_limits[VP_CODEC]; > > > > - while (i-- >= 0) > > + while (--i >= 0) > > if (camif_mbus_formats[i] == mf->code) > > break; > > - > > - mf->code = camif_mbus_formats[i]; > > + if (i < 0) > > + return; > > Thanks for the patch Dan. mf->width needs to be aligned by this try_format > function so we shouldn't return here. Also it needs to be ensured mf->code > is set to one of the supported values when this function returns. Sorry, > the current code really doesn't give a clue what was intended. > > There is already queued a patch from Arnd [1] addressing the issues you > have found. > > > if (pad == CAMIF_SD_PAD_SINK) { > > v4l_bound_align_image(&mf->width, 8, CAMIF_MAX_PIX_WIDTH, > > > > [1] https://patchwork.linuxtv.org/patch/46508 > Hey Arnd, I happened to be looking at the same bugs but using Smatch. Did you get these two bugs as well? drivers/scsi/sym53c8xx_2/sym_hipd.c:549 sym_getsync() error: iterator underflow 'div_10M' (-1)-255 drivers/media/i2c/sr030pc30.c:522 try_fmt() error: iterator underflow 'sr030pc30_formats' (-1)-4 regards, dan carpenter
On Wed, Jan 24, 2018 at 9:13 AM, Dan Carpenter <dan.carpenter@oracle.com> wrote: > On Mon, Jan 22, 2018 at 09:50:04PM +0100, Sylwester Nawrocki wrote: >> On 01/22/2018 11:37 AM, Dan Carpenter wrote: > I happened to be looking at the same bugs but using Smatch. Did you get > these two bugs as well? > > drivers/scsi/sym53c8xx_2/sym_hipd.c:549 sym_getsync() error: iterator underflow 'div_10M' (-1)-255 > drivers/media/i2c/sr030pc30.c:522 try_fmt() error: iterator underflow 'sr030pc30_formats' (-1)-4 I don't recall seeing those two, here is a list of array-bounds warnings I had in the past months, mostly while building with gcc-7.2: /git/arm-soc/arch/arm/mach-vexpress/spc.c:431:38: warning: array subscript is below array bounds [-Warray-bounds] /git/arm-soc/arch/x86/include/asm/string_32.h:70:16: error: array subscript is above array bounds [-Werror=array-bounds] /git/arm-soc/arch/x86/include/asm/uaccess_64.h:143:20: error: array subscript is above array bounds [-Werror=array-bounds] /git/arm-soc/drivers/cpufreq/arm_big_little.c:201:24: warning: array subscript is above array bounds [-Warray-bounds] /git/arm-soc/drivers/cpufreq/arm_big_little.c:325:16: warning: array subscript is above array bounds [-Warray-bounds] /git/arm-soc/drivers/cpufreq/arm_big_little.c:440:39: warning: array subscript is above array bounds [-Warray-bounds] /git/arm-soc/drivers/dma/sh/rcar-dmac.c:876:29: error: array subscript is above array bounds [-Werror=array-bounds] /git/arm-soc/drivers/isdn/hardware/eicon/message.c:11302:54: error: array subscript is above array bounds [-Werror=array-bounds] /git/arm-soc/drivers/net/ethernet/intel/igb/igb_ptp.c:367: error: array subscript is below array bounds /git/arm-soc/drivers/net/ethernet/intel/igb/igb_ptp.c:455: error: array subscript is below array bounds /git/arm-soc/drivers/scsi/qla2xxx/qla_gs.c:1398:7: error: array subscript is above array bounds [-Werror=array-bounds] /git/arm-soc/drivers/scsi/qla2xxx/qla_gs.c:2279:7: error: array subscript is above array bounds [-Werror=array-bounds] /git/arm-soc/drivers/scsi/sym53c416.c:565:58: error: array subscript is above array bounds [-Werror=array-bounds] /git/arm-soc/drivers/staging/lustre/lustre/ptlrpc/ptlrpcd.c:492:14: error: array subscript -1 is below array bounds of 'struct ptlrpcd_ctl[]' [-Werror=array-bounds] /git/arm-soc/fs/f2fs/segment.c:3044:5: error: array subscript is below array bounds [-Werror=array-bounds] /git/arm-soc/include/linux/compiler.h:253:20: error: array subscript is above array bounds [-Werror=array-bounds] /git/arm-soc/include/linux/dynamic_debug.h:86:20: warning: array subscript is above array bounds [-Warray-bounds] /git/arm-soc/include/sound/pcm.h:919:9: error: array subscript is above array bounds [-Werror=array-bounds] /git/arm-soc/kernel/bpf/verifier.c:4320:29: error: array subscript is above array bounds [-Werror=array-bounds] /git/arm-soc/kernel/rcu/tree.c:3332:13: warning: array subscript is above array bounds [-Warray-bounds] /git/arm-soc/net/ipv4/tcp_output.c:2129:40: error: array subscript is below array bounds [-Werror=array-bounds] /git/arm-soc/net/ipv4/tcp_output.c:2207:40: error: array subscript is below array bounds [-Werror=array-bounds] /git/arm-soc/net/rxrpc/ar-connection.c:589:16: warning: array subscript is above array bounds [-Warray-bounds] /git/arm-soc/sound/soc/sh/rcar/cmd.c:88:14: error: array subscript is below array bounds [-Werror=array-bounds] /git/arm-soc/sound/soc/sh/rcar/cmd.c:88: error: array subscript is below array bounds I've also opened two gcc bugs for warnings that appeared to be issued in error: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83312 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81601 I haven't built with gcc-8 in a while, should try that again now that PR83312 has been marked 'fixed'. Arnd
diff --git a/drivers/media/platform/s3c-camif/camif-capture.c b/drivers/media/platform/s3c-camif/camif-capture.c index 437395a61065..012f4b389c55 100644 --- a/drivers/media/platform/s3c-camif/camif-capture.c +++ b/drivers/media/platform/s3c-camif/camif-capture.c @@ -1261,11 +1261,11 @@ static void __camif_subdev_try_format(struct camif_dev *camif, /* FIXME: constraints against codec or preview path ? */ pix_lim = &variant->vp_pix_limits[VP_CODEC]; - while (i-- >= 0) + while (--i >= 0) if (camif_mbus_formats[i] == mf->code) break; - - mf->code = camif_mbus_formats[i]; + if (i < 0) + return; if (pad == CAMIF_SD_PAD_SINK) { v4l_bound_align_image(&mf->width, 8, CAMIF_MAX_PIX_WIDTH,
The while loop is a post op, "while (i-- >= 0)" so the last iteration will read camif_mbus_formats[-1] and then the loop will exit with "i" set to -2 and so we do: "mf->code = camif_mbus_formats[-2];". I've changed it to a pre-op, I've added a check to ensure we found the right format and I've removed the "mf->code = camif_mbus_formats[i];" because that is a no-op anyway. Fixes: babde1c243b2 ("[media] V4L: Add driver for S3C24XX/S3C64XX SoC series camera interface") Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>