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[v4,0/6] Memory corruption may occur due to incorrent tlb flush

Message ID 20200520083025.229011-1-santosh@fossix.org
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Series Memory corruption may occur due to incorrent tlb flush | expand

Message

Santosh Sivaraj May 20, 2020, 8:30 a.m. UTC 
The TLB flush optimisation (a46cc7a90f: powerpc/mm/radix: Improve TLB/PWC
flushes) may result in random memory corruption. Any concurrent page-table walk
could end up with a Use-after-Free. Even on UP this might give issues, since
mmu_gather is preemptible these days. An interrupt or preempted task accessing
user pages might stumble into the free page if the hardware caches page
directories.

The series is a backport of the fix sent by Peter [1].

The first three patches are dependencies for the last patch (avoid potential
double flush). If the performance impact due to double flush is considered
trivial then the first three patches and last patch may be dropped.

This is only for v4.19 stable.
--
Changelog:
 v2: Send the patches with the correct format (commit sha1 upstream) for stable
 v3: Fix compilation for ppc44x_defconfig and mpc885_ads_defconfig
 v4: No change, Resend.

--
Aneesh Kumar K.V (1):
  powerpc/mmu_gather: enable RCU_TABLE_FREE even for !SMP case

Peter Zijlstra (4):
  asm-generic/tlb: Track freeing of page-table directories in struct
    mmu_gather
  asm-generic/tlb, arch: Invert CONFIG_HAVE_RCU_TABLE_INVALIDATE
  mm/mmu_gather: invalidate TLB correctly on batch allocation failure
    and flush
  asm-generic/tlb: avoid potential double flush

Will Deacon (1):
  asm-generic/tlb: Track which levels of the page tables have been
    cleared

 arch/Kconfig                                 |   3 -
 arch/powerpc/Kconfig                         |   2 +-
 arch/powerpc/include/asm/book3s/32/pgalloc.h |   8 --
 arch/powerpc/include/asm/book3s/64/pgalloc.h |   2 -
 arch/powerpc/include/asm/nohash/32/pgalloc.h |   8 --
 arch/powerpc/include/asm/tlb.h               |  11 ++
 arch/powerpc/mm/pgtable-book3s64.c           |   7 --
 arch/sparc/include/asm/tlb_64.h              |   9 ++
 arch/x86/Kconfig                             |   1 -
 include/asm-generic/tlb.h                    | 103 ++++++++++++++++---
 mm/memory.c                                  |  20 ++--
 11 files changed, 122 insertions(+), 52 deletions(-)