[PATCH] ASoC: ops: Fix wraparound for mask in snd_soc_get_volsw

From: Stephen Lee
Date: Mon Mar 25 2024 - 21:02:52 EST


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@xxxxxxxxx>
---

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