On Thu 17-05-18 18:49:47, Michal Hocko wrote: > On Thu 17-05-18 16:58:32, Ville Syrjälä wrote: > > On Thu, May 17, 2018 at 04:36:29PM +0300, Ville Syrjälä wrote: > > > On Thu, May 17, 2018 at 03:21:09PM +0200, Michal Hocko wrote: > > > > On Thu 17-05-18 15:59:59, Ville Syrjala wrote: > > > > > From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> > > > > > > > > > > This reverts commit bad8c6c0b1144694ecb0bc5629ede9b8b578b86e. > > > > > > > > > > Make x86 with HIGHMEM=y and CMA=y boot again. > > > > > > > > Is there any bug report with some more details? It is much more > > > > preferable to fix the issue rather than to revert the whole thing > > > > right away. > > > > > > The machine I have in front of me right now didn't give me anything. > > > Black screen, and netconsole was silent. No serial port on this > > > machine unfortunately. > > > > Booted on another machine with serial: > > Could you provide your .config please? > > [...] > > [ 0.000000] cma: Reserved 4 MiB at 0x0000000037000000 > [...] > > [ 0.000000] BUG: Bad page state in process swapper pfn:377fe > > [ 0.000000] page:f53effc0 count:0 mapcount:-127 mapping:00000000 index:0x0 > > OK, so this looks the be the source of the problem. -128 would be a > buddy page but I do not see anything that would set the counter to -127 > and the real map count updates shouldn't really happen that early. > > Maybe CONFIG_DEBUG_VM and CONFIG_DEBUG_HIGHMEM will tell us more. Looking closer, I _think_ that the bug is in set_highmem_pages_init->is_highmem and zone_movable_is_highmem might force CMA pages in the zone movable to be initialized as highmem. And that sounds supicious to me. Joonsoo? -- Michal Hocko SUSE Labs
