On 19.12.18 14:46, Frieder Schrempf wrote: > Hi Sebastian, > > On 19.12.18 12:36, Sebastian Andrzej Siewior wrote: >> On 2018-12-19 07:50:17 [+0000], Schrempf Frieder wrote: >>> + linux-rt-users >>> >>> On 17.12.18 11:42, Frieder Schrempf wrote: >>>> Hi, >>>> >>>> I have tried to boot a 4.14-Kernel with the RT-patches and >>>> PREEMPT_RT_FULL on an i.MX6UL board. Unfortunately the boot stalls at >>>> some point and never finishes. >>>> >>>> I did some bisecting and found out, that reverting this change: [1], >>>> makes the board boot correctly. >>>> >>>> Can anyone help to come up with a proper fix for this? >> >> can you check if the hashtable is initialized twice? > > I'm not sure how to check, but I guess you are on the right track. I can > leave the init loop for dentry_hashtable in place and remove the one for > in_lookup_hashtable in vfs_caches_init_early() and this also makes the > board boot. > > Could it be, that the initializing for dentry_hashtable and > in_lookup_hashtable somehow interfere? So the source of the issue turned out to be completely unrelated to this. Although it seems like enabling PREEMPT_RT_FULL triggered the problem in my case. The lockup of the kernel was caused by the SNVS RTC driver. Pulling in this patch: [1], solved the problem. As this patch fixes a real bug I sent a request for it to be backported to the stable releases. [1]: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=cd7f3a249dbed2858e6c2f30e5be7f1f7a709ee2 >>>> >>>> [1]: >>>> https://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-stable-rt.git/commit/?h=v4.14-rt&id=56684d21f7f8341f7a5ed1433714112f49294590 >>>> >> >> Sebastian >>
