Messages in this thread | | | Date | Mon, 15 Jul 2019 17:44:18 +0200 | From | Joerg Roedel <> | Subject | Re: [PATCH 1/3] x86/mm: Check for pfn instead of page in vmalloc_sync_one() |
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On Mon, Jul 15, 2019 at 03:08:42PM +0200, Thomas Gleixner wrote: > On Mon, 15 Jul 2019, Joerg Roedel wrote: > > > From: Joerg Roedel <jroedel@suse.de> > > > > Do not require a struct page for the mapped memory location > > because it might not exist. This can happen when an > > ioremapped region is mapped with 2MB pages. > > > > Signed-off-by: Joerg Roedel <jroedel@suse.de> > > Lacks a Fixes tag, hmm?
Yeah, right, the question is, which commit to put in there. The problem results from two changes:
1) Introduction of !SHARED_KERNEL_PMD path in x86-32. In itself this is not a problem, and the path was only enabled for Xen-PV.
2) Huge IORemapings which use the PMD level. Also not a problem by itself, but together with !SHARED_KERNEL_PMD problematic because it requires to sync the PMD entries between all page-tables, and that was not implemented.
Before PTI-x32 was merged this problem did not show up, maybe because the 32-bit Xen-PV users did not trigger it. But with PTI-x32 all PAE users run with !SHARED_KERNEL_PMD and the problem popped up.
For the last patch I put the PTI-x32 enablement commit in the fixes tag, because that was the one that showed up during bisection. But more correct would probably be
5d72b4fba40e ('x86, mm: support huge I/O mapping capability I/F')
Or do I miss something?
Regards,
Joerg
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