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From: Stephen Lee <slee08177@gmail.com>
To: lgirdwood@gmail.com, broonie@kernel.org, perex@perex.cz, tiwai@suse.com
Cc: alsa-devel@alsa-project.org, linux-kernel@vger.kernel.org,
	linux-sound@vger.kernel.org, roman.gushchin@linux.dev,
	dennis@kernel.org, Stephen Lee <slee08177@gmail.com>
Subject: [PATCH] ASoC: ops: Fix wraparound for mask in snd_soc_get_volsw
Date: Mon, 25 Mar 2024 18:01:31 -0700	[thread overview]
Message-ID: <20240326010131.6211-1-slee08177@gmail.com> (raw)

In snd_soc_info_volsw(), mask is generated by figuring out the index of
the most significant bit set in max and converting the index to a
bitmask through bit shift 1. Unintended wraparound occurs when max is an
integer value with msb bit set. Since the bit shift value 1 is treated
as an integer type, the left shift operation will wraparound and set
mask to 0 instead of all 1's. In order to fix this, we type cast 1 as
`1ULL` to prevent the wraparound.

Fixes: 7077148fb50a ("ASoC: core: Split ops out of soc-core.c")
Signed-off-by: Stephen Lee <slee08177@gmail.com>
---

This seems to show up in quite a few places in the alsa subsystem,
should they be addressed altogether?

---
 sound/soc/soc-ops.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sound/soc/soc-ops.c b/sound/soc/soc-ops.c
index 2d25748ca706..b27e89ff6a16 100644
--- a/sound/soc/soc-ops.c
+++ b/sound/soc/soc-ops.c
@@ -263,7 +263,7 @@ int snd_soc_get_volsw(struct snd_kcontrol *kcontrol,
 	int max = mc->max;
 	int min = mc->min;
 	int sign_bit = mc->sign_bit;
-	unsigned int mask = (1 << fls(max)) - 1;
+	unsigned int mask = (1ULL << fls(max)) - 1;
 	unsigned int invert = mc->invert;
 	int val;
 	int ret;
-- 
2.43.2


             reply	other threads:[~2024-03-26  1:02 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-03-26  1:01 Stephen Lee [this message]
2024-03-28 19:28 ` [PATCH] ASoC: ops: Fix wraparound for mask in snd_soc_get_volsw Mark Brown
2024-03-29  1:29 ` Mark Brown

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