pcm: dshare - fix shared memory pointer check

alsa-project/alsa-lib pull request #128 was opened from VanithaChannaiah:

Currently shared memory pointer is initialized to 0 and set to -1 in some, but not in all error paths. In cleanup path of open the shm pointer is only compared to be non-NULL before dereferencing it which leads to SEGFAULT in case it was set to -1.

This patch initializes pointer to -1 to have a unique identification for invalid pointer and also checks for pointer being not -1 on access in cleanup path.

Signed-off-by: Vanitha Channaiah vanitha.channaiah@in.bosch.com

Request URL : https://github.com/alsa-project/alsa-lib/pull/128 Patch URL : https://github.com/alsa-project/alsa-lib/pull/128.patch Repository URL: https://github.com/alsa-project/alsa-lib