aboutsummaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
authorPeter Xu <peterx@redhat.com>2022-11-08 15:57:23 -0800
committerAndrew Morton <akpm@linux-foundation.org>2022-11-08 15:57:23 -0800
commit624a2c94f5b7a08120aaf26b3275a17463789273 (patch)
treecd64a6dfccf7520e101d2ab2c943767b6d6d6268
parent8ac932a4921a96ca52f61935dbba64ea87bbd5dc (diff)
downloadlinux-624a2c94f5b7a08120aaf26b3275a17463789273.tar.gz
Partly revert "mm/thp: carry over dirty bit when thp splits on pmd"
Anatoly Pugachev reported sparc64 breakage on the patch: https://lore.kernel.org/r/20221021160603.GA23307@u164.east.ru The sparc64 impl of pte_mkdirty() is definitely slightly special in that it leverages a code patching mechanism for sun4u/sun4v on relevant pgtable entry operations. Before having a clue of why the sparc64 is special and caused the patch to SIGSEGV the processes, revert the patch for now. The swap path of dirty bit inheritage is kept because that's using the swap shared code so we assume it'll not be affected. Link: https://lkml.kernel.org/r/Y1Wbi4yyVvDtg4zN@x1n Fixes: 0ccf7f168e17 ("mm/thp: carry over dirty bit when thp splits on pmd") Signed-off-by: Peter Xu <peterx@redhat.com> Reported-by: Anatoly Pugachev <matorola@gmail.com> Tested-by: Anatoly Pugachev <matorola@gmail.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Andi Kleen <andi.kleen@intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: David Hildenbrand <david@redhat.com> Cc: David S. Miller <davem@davemloft.net> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Hugh Dickins <hughd@google.com> Cc: "Kirill A . Shutemov" <kirill@shutemov.name> Cc: Minchan Kim <minchan@kernel.org> Cc: Nadav Amit <nadav.amit@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
-rw-r--r--mm/huge_memory.c9
1 files changed, 6 insertions, 3 deletions
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 561a42567477d..811d19b5c4f60 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2206,9 +2206,12 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd,
entry = pte_wrprotect(entry);
if (!young)
entry = pte_mkold(entry);
- /* NOTE: this may set soft-dirty too on some archs */
- if (dirty)
- entry = pte_mkdirty(entry);
+ /*
+ * NOTE: we don't do pte_mkdirty when dirty==true
+ * because it breaks sparc64 which can sigsegv
+ * random process. Need to revisit when we figure
+ * out what is special with sparc64.
+ */
if (soft_dirty)
entry = pte_mksoft_dirty(entry);
if (uffd_wp)