[PATCH 2/2] ALSA: compress_offload: avoid 64-bit get_user()

From: Arnd Bergmann
Date: Mon Dec 16 2024 - 04:34:45 EST


From: Arnd Bergmann <arnd@xxxxxxxx>

On some architectures, get_user() cannot read a 64-bit user variable:

arm-linux-gnueabi-ld: sound/core/compress_offload.o: in function `snd_compr_ioctl':
compress_offload.c:(.text.snd_compr_ioctl+0x538): undefined reference to `__get_user_bad'

Use an equivalent copy_from_user() instead.

Fixes: 04177158cf98 ("ALSA: compress_offload: introduce accel operation mode")
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
---
sound/core/compress_offload.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/sound/core/compress_offload.c b/sound/core/compress_offload.c
index ec2485c00e49..1d6769a66810 100644
--- a/sound/core/compress_offload.c
+++ b/sound/core/compress_offload.c
@@ -1180,9 +1180,9 @@ static int snd_compr_task_seq(struct snd_compr_stream *stream, unsigned long arg

if (stream->runtime->state != SNDRV_PCM_STATE_SETUP)
return -EPERM;
- retval = get_user(seqno, (__u64 __user *)arg);
- if (retval < 0)
- return retval;
+ retval = copy_from_user(&seqno, (__u64 __user *)arg, sizeof(seqno));
+ if (retval)
+ return -EFAULT;
retval = 0;
if (seqno == 0) {
list_for_each_entry_reverse(task, &stream->runtime->tasks, list)
--
2.39.5