[PATCH] ALSA: hwdep: fix a left shifting 1 by 31 UB bug

[Changming Liu]

The "info.index" variable can be 31 in "1 << info.index".
This might trigger an undefined behavior since 1 is signed.

Fix this by casting 1 to 1u just to be sure "1u << 31" is defined.

Signed-off-by: Changming Liu <liu.changm at northeastern.edu>
---
 sound/core/hwdep.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/sound/core/hwdep.c b/sound/core/hwdep.c
index b412d3b3d5ff..21edb8ac95eb 100644
--- a/sound/core/hwdep.c
+++ b/sound/core/hwdep.c
@@ -216,12 +216,12 @@ static int snd_hwdep_dsp_load(struct snd_hwdep *hw,
        if (info.index >= 32)
                return -EINVAL;
        /* check whether the dsp was already loaded */
-       if (hw->dsp_loaded & (1 << info.index))
+       if (hw->dsp_loaded & (1u << info.index))
                return -EBUSY;
        err = hw->ops.dsp_load(hw, &info);
        if (err < 0)
                return err;
-       hw->dsp_loaded |= (1 << info.index);
+       hw->dsp_loaded |= (1u << info.index);
        return 0;
 }

--
2.17.1