Re: DRM-current-kmod is still a problem at r353339

On Thu, Oct 17, 2019 at 03:03:51PM +0200, Niclas Zeising wrote:
> On 2019-10-16 18:57, Neel Chauhan wrote:
> > While drm-current-kmod worked for a little while, it broke with r353645.
> > 
> > https://i.imgur.com/Q5nYZf2.jpg
> > 
> > I'm using the same HP Spectre that I used earlier (where it worked and 
> > where it panicked).
> > 
> 
> That commit looks unrelated, it touches the wbwd and superio drivers, 
> nothing else.  Any chance you can bisect exactly which revision that 
> caused the new issues?

I believe it was the recent work on the vm page busy state, r353539
specifically.  This patch should fix it; we don't yet have a
__FreeBSD_version number bump on which to gate the patch.

diff --git a/linuxkpi/gplv2/src/linux_page.c b/linuxkpi/gplv2/src/linux_page.c
index e2b85c45c..060ae85ed 100644
--- a/linuxkpi/gplv2/src/linux_page.c
+++ b/linuxkpi/gplv2/src/linux_page.c
_at__at_ -239,7 +239,7 _at__at_ retry:
 			page = vm_page_lookup(devobj, i);
 			if (page == NULL)
 				continue;
-			if (vm_page_sleep_if_busy(page, "linuxkpi"))
+			if (!vm_page_busy_acquire(page, VM_ALLOC_WAITFAIL))
 				goto retry;
 			cdev_pager_free_page(devobj, page);
 		}