The quilt patch titled
Subject: perf/core: allow pte_offset_map() to fail
has been removed from the -mm tree. Its filename was
perf-core-allow-pte_offset_map-to-fail.patch
This patch was dropped because it was merged into the mm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
------------------------------------------------------
From: Hugh Dickins <hughd@xxxxxxxxxx>
Subject: perf/core: allow pte_offset_map() to fail
Date: Thu, 8 Jun 2023 18:53:23 -0700 (PDT)
In rare transient cases, not yet made possible, pte_offset_map() and
pte_offet_map_lock() may not find a page table: handle appropriately.
[hughd@xxxxxxxxxx: __wp_page_copy_user(): don't call update_mmu_tlb() with NULL]
Link: https://lkml.kernel.org/r/1a4db221-7872-3594-57ce-42369945ec8d@xxxxxxxxxx
Link: https://lkml.kernel.org/r/a194441b-63f3-adb6-5964-7ca3171ae7c2@xxxxxxxxxx
Signed-off-by: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Alistair Popple <apopple@xxxxxxxxxx>
Cc: Anshuman Khandual <anshuman.khandual@xxxxxxx>
Cc: Axel Rasmussen <axelrasmussen@xxxxxxxxxx>
Cc: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: "Huang, Ying" <ying.huang@xxxxxxxxx>
Cc: Ira Weiny <ira.weiny@xxxxxxxxx>
Cc: Jason Gunthorpe <jgg@xxxxxxxx>
Cc: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Lorenzo Stoakes <lstoakes@xxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Cc: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Cc: Mike Rapoport (IBM) <rppt@xxxxxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Cc: Naoya Horiguchi <naoya.horiguchi@xxxxxxx>
Cc: Pavel Tatashin <pasha.tatashin@xxxxxxxxxx>
Cc: Peter Xu <peterx@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Qi Zheng <zhengqi.arch@xxxxxxxxxxxxx>
Cc: Ralph Campbell <rcampbell@xxxxxxxxxx>
Cc: Ryan Roberts <ryan.roberts@xxxxxxx>
Cc: SeongJae Park <sj@xxxxxxxxxx>
Cc: Song Liu <song@xxxxxxxxxx>
Cc: Steven Price <steven.price@xxxxxxx>
Cc: Suren Baghdasaryan <surenb@xxxxxxxxxx>
Cc: Thomas Hellström <thomas.hellstrom@xxxxxxxxxxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Cc: Yang Shi <shy828301@xxxxxxxxx>
Cc: Yu Zhao <yuzhao@xxxxxxxxxx>
Cc: Zack Rusin <zackr@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/events/core.c | 4 ++++
mm/memory.c | 6 ++++--
2 files changed, 8 insertions(+), 2 deletions(-)
--- a/kernel/events/core.c~perf-core-allow-pte_offset_map-to-fail
+++ a/kernel/events/core.c
@@ -7490,6 +7490,7 @@ static u64 perf_get_pgtable_size(struct
return pud_leaf_size(pud);
pmdp = pmd_offset_lockless(pudp, pud, addr);
+again:
pmd = pmdp_get_lockless(pmdp);
if (!pmd_present(pmd))
return 0;
@@ -7498,6 +7499,9 @@ static u64 perf_get_pgtable_size(struct
return pmd_leaf_size(pmd);
ptep = pte_offset_map(&pmd, addr);
+ if (!ptep)
+ goto again;
+
pte = ptep_get_lockless(ptep);
if (pte_present(pte))
size = pte_leaf_size(pte);
--- a/mm/memory.c~perf-core-allow-pte_offset_map-to-fail
+++ a/mm/memory.c
@@ -2843,7 +2843,8 @@ static inline int __wp_page_copy_user(st
* Other thread has already handled the fault
* and update local tlb only
*/
- update_mmu_tlb(vma, addr, vmf->pte);
+ if (vmf->pte)
+ update_mmu_tlb(vma, addr, vmf->pte);
ret = -EAGAIN;
goto pte_unlock;
}
@@ -2867,7 +2868,8 @@ static inline int __wp_page_copy_user(st
vmf->pte = pte_offset_map_lock(mm, vmf->pmd, addr, &vmf->ptl);
if (unlikely(!vmf->pte || !pte_same(*vmf->pte, vmf->orig_pte))) {
/* The PTE changed under us, update local tlb */
- update_mmu_tlb(vma, addr, vmf->pte);
+ if (vmf->pte)
+ update_mmu_tlb(vma, addr, vmf->pte);
ret = -EAGAIN;
goto pte_unlock;
}
_
Patches currently in -mm which might be from hughd@xxxxxxxxxx are
