Commit 0c5f83c23ca703d32f930393825487257a5cde6d
Committed by
Linus Torvalds
Linus Torvalds
1 parent
5a6dac3ec5
Exists in
master
and in
16 other branches
mm: numa: do not clear PTE for pte_numa update
The TLB must be flushed if the PTE is updated but change_pte_range is clearing the PTE while marking PTEs pte_numa without necessarily flushing the TLB if it reinserts the same entry. Without the flush, it's conceivable that two processors have different TLBs for the same virtual address and at the very least it would generate spurious faults. This patch only unmaps the pages in change_pte_range for a full protection change. [riel@redhat.com: write pte_numa pte back to the page tables] Signed-off-by: Mel Gorman <mgorman@suse.de> Signed-off-by: Rik van Riel <riel@redhat.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Alex Thorlton <athorlton@sgi.com> Cc: Chegu Vinod <chegu_vinod@hp.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Showing 1 changed file with 7 additions and 2 deletions Side-by-side Diff
mm/mprotect.c
| ... | ... | @@ -52,17 +52,19 @@ |
| 52 | 52 | pte_t ptent; |
| 53 | 53 | bool updated = false; |
| 54 | 54 | |
| 55 | - ptent = ptep_modify_prot_start(mm, addr, pte); | |
| 56 | 55 | if (!prot_numa) { |
| 56 | + ptent = ptep_modify_prot_start(mm, addr, pte); | |
| 57 | 57 | ptent = pte_modify(ptent, newprot); |
| 58 | 58 | updated = true; |
| 59 | 59 | } else { |
| 60 | 60 | struct page *page; |
| 61 | 61 | |
| 62 | + ptent = *pte; | |
| 62 | 63 | page = vm_normal_page(vma, addr, oldpte); |
| 63 | 64 | if (page) { |
| 64 | 65 | if (!pte_numa(oldpte)) { |
| 65 | 66 | ptent = pte_mknuma(ptent); |
| 67 | + set_pte_at(mm, addr, pte, ptent); | |
| 66 | 68 | updated = true; |
| 67 | 69 | } |
| 68 | 70 | } |
| ... | ... | @@ -79,7 +81,10 @@ |
| 79 | 81 | |
| 80 | 82 | if (updated) |
| 81 | 83 | pages++; |
| 82 | - ptep_modify_prot_commit(mm, addr, pte, ptent); | |
| 84 | + | |
| 85 | + /* Only !prot_numa always clears the pte */ | |
| 86 | + if (!prot_numa) | |
| 87 | + ptep_modify_prot_commit(mm, addr, pte, ptent); | |
| 83 | 88 | } else if (IS_ENABLED(CONFIG_MIGRATION) && !pte_file(oldpte)) { |
| 84 | 89 | swp_entry_t entry = pte_to_swp_entry(oldpte); |
| 85 | 90 |