On Sun, 14 Aug 2016 02:28:52 +0200, Ismael Luceno wrote:
Easily seen when two threads try at the same time, one of them will fail.
The bug was identified by using apulse with Skype.
Fixes: dec428c35221 ("pcm: fix 'unable to create IPC shm instance' caused by fork from a thread") Fixes: https://github.com/i-rinat/apulse/issues/38 Signed-off-by: Ismael Luceno ismael@iodev.co.uk
src/pcm/pcm_direct.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/src/pcm/pcm_direct.c b/src/pcm/pcm_direct.c index c3925cc20fd3..b5215ba35406 100644 --- a/src/pcm/pcm_direct.c +++ b/src/pcm/pcm_direct.c @@ -101,6 +101,8 @@ retryget: if ((dmix->shmid = shmget(dmix->ipc_key, sizeof(snd_pcm_direct_share_t), IPC_CREAT | IPC_EXCL | dmix->ipc_perm)) != -1) first_instance = 1;
if (dmix->shmid < 0 && errno == EEXIST)goto retryget;
Hrm, but this would result in an endless loop if the shm was already taken persistently.
Also, which call does give a negative shmid, actually? It's from the first shmget() or the second shmget()? (The existing code is ugly and we need to fix the indentation there...)
thanks,
Takashi