On Thu, 03 Dec 2015 06:32:09 +0100, Ravindra Lokhande wrote:

Compress offload does not support ioctl calls from a 32bit userspace in a 64 bit kernel. This patch adds support for ioctls from a 32bit userspace in a 64bit kernel

Signed-off-by: Ravindra Lokhande rlokhande@nvidia.com

sound/core/compress_offload.c | 12 ++++++++++++ 1 file changed, 12 insertions(+)

diff --git a/sound/core/compress_offload.c b/sound/core/compress_offload.c index b123c42..98f6b47 100644 --- a/sound/core/compress_offload.c +++ b/sound/core/compress_offload.c @@ -847,6 +847,15 @@ static long snd_compr_ioctl(struct file *f, unsigned int cmd, unsigned long arg) return retval; }

+/* support of 32bit userspace on 64bit platforms */ +#ifdef CONFIG_COMPAT +static long snd_compr_ioctl_compat(struct file *file, unsigned int cmd,

• 				unsigned long arg)
  

+{

• return snd_compr_ioctl(file, cmd, arg);

+} +#endif

This should work in most cases, but not perfectly. The arg passed here is basically a 32bit address, and it should be converted to a 64bit pointer via compat_ptr() macro. Except for a very few architectures, it's just a cast to 64bit, so it works in 99% cases.

A workaround would be like:

static long snd_compr_ioctl_compat(struct file *file, unsigned int cmd, unsigned long arg) { return snd_compr_ioctl(file, cmd, (long)compat_ptr(arg)); }

I looked through the current tree and found even a few places in sound/core/* doing similarly wrong. They need fixes...

thanks,

Takashi

static const struct file_operations snd_compr_file_ops = { .owner = THIS_MODULE, .open = snd_compr_open, @@ -854,6 +863,9 @@ static const struct file_operations snd_compr_file_ops = { .write = snd_compr_write, .read = snd_compr_read, .unlocked_ioctl = snd_compr_ioctl, +#ifdef CONFIG_COMPAT

• .compat_ioctl = snd_compr_ioctl_compat,
  

+#endif .mmap = snd_compr_mmap, .poll = snd_compr_poll, }; -- 2.1.4