[alsa-devel] [PATCH] ASoC: sgtl5000: avoid division by zero if lo_vag is zero
From: Colin Ian King colin.king@canonical.com
In the case where lo_vag <= SGTL5000_LINE_OUT_GND_BASE, lo_vag is set to zero and later vol_quot is computed by dividing by lo_vag causing a division by zero error. Fix this by avoiding a zero division and set vol_quot to zero in this specific case so that the lowest setting for i is correctly set.
Signed-off-by: Colin Ian King colin.king@canonical.com --- sound/soc/codecs/sgtl5000.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/sound/soc/codecs/sgtl5000.c b/sound/soc/codecs/sgtl5000.c index 60764f6201b1..add18d6d77da 100644 --- a/sound/soc/codecs/sgtl5000.c +++ b/sound/soc/codecs/sgtl5000.c @@ -1218,7 +1218,7 @@ static int sgtl5000_set_power_regs(struct snd_soc_component *component) * Searching for a suitable index solving this formula: * idx = 40 * log10(vag_val / lo_cagcntrl) + 15 */ - vol_quot = (vag * 100) / lo_vag; + vol_quot = lo_vag ? (vag * 100) / lo_vag : 0; lo_vol = 0; for (i = 0; i < ARRAY_SIZE(vol_quot_table); i++) { if (vol_quot >= vol_quot_table[i])
The patch
ASoC: sgtl5000: avoid division by zero if lo_vag is zero
has been applied to the asoc tree at
https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound.git
All being well this means that it will be integrated into the linux-next tree (usually sometime in the next 24 hours) and sent to Linus during the next merge window (or sooner if it is a bug fix), however if problems are discovered then the patch may be dropped or reverted.
You may get further e-mails resulting from automated or manual testing and review of the tree, please engage with people reporting problems and send followup patches addressing any issues that are reported if needed.
If any updates are required or you are submitting further changes they should be sent as incremental updates against current git, existing patches will not be replaced.
Please add any relevant lists and maintainers to the CCs when replying to this mail.
Thanks, Mark
From 9ab708aef61f5620113269a9d1bdb1543d1207d0 Mon Sep 17 00:00:00 2001
From: Colin Ian King colin.king@canonical.com Date: Thu, 6 Sep 2018 11:41:52 +0100 Subject: [PATCH] ASoC: sgtl5000: avoid division by zero if lo_vag is zero
In the case where lo_vag <= SGTL5000_LINE_OUT_GND_BASE, lo_vag is set to zero and later vol_quot is computed by dividing by lo_vag causing a division by zero error. Fix this by avoiding a zero division and set vol_quot to zero in this specific case so that the lowest setting for i is correctly set.
Signed-off-by: Colin Ian King colin.king@canonical.com Signed-off-by: Mark Brown broonie@kernel.org --- sound/soc/codecs/sgtl5000.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/sound/soc/codecs/sgtl5000.c b/sound/soc/codecs/sgtl5000.c index 60764f6201b1..add18d6d77da 100644 --- a/sound/soc/codecs/sgtl5000.c +++ b/sound/soc/codecs/sgtl5000.c @@ -1218,7 +1218,7 @@ static int sgtl5000_set_power_regs(struct snd_soc_component *component) * Searching for a suitable index solving this formula: * idx = 40 * log10(vag_val / lo_cagcntrl) + 15 */ - vol_quot = (vag * 100) / lo_vag; + vol_quot = lo_vag ? (vag * 100) / lo_vag : 0; lo_vol = 0; for (i = 0; i < ARRAY_SIZE(vol_quot_table); i++) { if (vol_quot >= vol_quot_table[i])
On Thu, Sep 06, 2018 at 11:41:52AM +0100, Colin King wrote:
From: Colin Ian King colin.king@canonical.com
In the case where lo_vag <= SGTL5000_LINE_OUT_GND_BASE, lo_vag is set to zero and later vol_quot is computed by dividing by lo_vag causing a division by zero error. Fix this by avoiding a zero division and set vol_quot to zero in this specific case so that the lowest setting for i is correctly set.
This is a very clever patch. How did you find the bug?
regards, dan carpenter
On 06/09/18 12:58, Dan Carpenter wrote:
On Thu, Sep 06, 2018 at 11:41:52AM +0100, Colin King wrote:
From: Colin Ian King colin.king@canonical.com
In the case where lo_vag <= SGTL5000_LINE_OUT_GND_BASE, lo_vag is set to zero and later vol_quot is computed by dividing by lo_vag causing a division by zero error. Fix this by avoiding a zero division and set vol_quot to zero in this specific case so that the lowest setting for i is correctly set.
This is a very clever patch. How did you find the bug?
trawling through a lot of false positives from a recent cppcheck run
regards, dan carpenter
participants (4)
-
Colin Ian King
-
Colin King
-
Dan Carpenter
-
Mark Brown