Re: [LAU] JACK hangs on openSUSE Tumbleweed

Hi *! I've come across a mysterious problem - since a few days ago (openSUSE Tumbleweed is a rolling release), JACK hangs during startup. If you start it with QJackCtl, it will kill it after a while, but if you start it from the console and strace it, you can see it hangs waiting for a futex: [...] sched_get_priority_min(SCHED_FIFO) = 1 sched_get_priority_max(SCHED_FIFO) = 99 mmap(NULL, 8392704, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_STACK, -1, 0) = 0x7f9e76cfe000 mprotect(0x7f9e76cfe000, 4096, PROT_NONE) = 0 clone(child_stack=0x7f9e774fdfb0, flags=CLONE_VM|CLONE_FS|CLONE_FILES|CLONE_SIGHAND|CLONE_THREAD|CLONE_SYSVSEM|CLONE_SETTLS|CLONE_PARENT_SETTID|CLONE_CHILD_CLEARTID, parent_tidptr=0x7f9e774fe9d0, tls=0x7f9e774fe700, child_tidptr=0x7f9e774fe9d0) = 4627 sched_setscheduler(4627, SCHED_FIFO, { 1 }) = 0 futex(0x7f9e774fed18, FUTEX_WAKE_PRIVATE, 1) = 1 munmap(0x7f9e7ba87000, 227354) = 0 futex(0x7f9e776ff078, FUTEX_WAKE_PRIVATE, 1) = 1 futex(0x7f9e774fe9d0, FUTEX_WAIT, 4627, NULL) = ? ERESTARTSYS (To be restarted if SA_RESTART is set) --- SIGWINCH {si_signo=SIGWINCH, si_code=SI_KERNEL} --- futex(0x7f9e774fe9d0, FUTEX_WAIT, 4627, NULL and hangs forever after. It seems to be after acquiring SCHED_FIFO, but just to be sure I verified that I'm still in group audio, and we still have @audio - rtprio 95 @audio - memlock 3000000 in /etc/security/limits.conf. The problem started at the same time kernel 3.19.3 came out for Tumbleweed, but downgrading to older kernels in the 3.19 series or as far back as 3.17 doesn't restore jack functionality. So it must be something in userspace.