diff options
| author | Nadav Amit <namit@vmware.com> | 2021-11-21 12:40:07 -0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-12-08 08:46:52 +0100 |
| commit | 7bf1f5cb5150b1a53f6ccaadc0bc77f8f33206c8 (patch) | |
| tree | c951758c413d07aad9055ca69e8cb77ad384ee41 /include/asm-generic | |
| parent | c755a93aa05e6e4ccdd3a5e921c0dd36f5c22c8b (diff) | |
hugetlbfs: flush TLBs correctly after huge_pmd_unshare
commit a4a118f2eead1d6c49e00765de89878288d4b890 upstream.
When __unmap_hugepage_range() calls to huge_pmd_unshare() succeed, a TLB
flush is missing. This TLB flush must be performed before releasing the
i_mmap_rwsem, in order to prevent an unshared PMDs page from being
released and reused before the TLB flush took place.
Arguably, a comprehensive solution would use mmu_gather interface to
batch the TLB flushes and the PMDs page release, however it is not an
easy solution: (1) try_to_unmap_one() and try_to_migrate_one() also call
huge_pmd_unshare() and they cannot use the mmu_gather interface; and (2)
deferring the release of the page reference for the PMDs page until
after i_mmap_rwsem is dropeed can confuse huge_pmd_unshare() into
thinking PMDs are shared when they are not.
Fix __unmap_hugepage_range() by adding the missing TLB flush, and
forcing a flush when unshare is successful.
Fixes: 24669e58477e ("hugetlb: use mmu_gather instead of a temporary linked list for accumulating pages)" # 3.6
Signed-off-by: Nadav Amit <namit@vmware.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'include/asm-generic')
| -rw-r--r-- | include/asm-generic/tlb.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/include/asm-generic/tlb.h b/include/asm-generic/tlb.h index faddde44de8c..5e7e4aaf36c5 100644 --- a/include/asm-generic/tlb.h +++ b/include/asm-generic/tlb.h @@ -117,6 +117,8 @@ void arch_tlb_gather_mmu(struct mmu_gather *tlb, void tlb_flush_mmu(struct mmu_gather *tlb); void arch_tlb_finish_mmu(struct mmu_gather *tlb, unsigned long start, unsigned long end, bool force); +void tlb_flush_pmd_range(struct mmu_gather *tlb, unsigned long address, + unsigned long size); extern bool __tlb_remove_page_size(struct mmu_gather *tlb, struct page *page, int page_size); |