On Wed, Jun 06, 2018 at 12:31:19PM +0530, Chintan Pandya wrote: > From: Chintan Pandya <[email protected]> > > The following kernel panic was observed on ARM64 platform due to a stale > TLB entry. > > 1. ioremap with 4K size, a valid pte page table is set. > 2. iounmap it, its pte entry is set to 0. > 3. ioremap the same address with 2M size, update its pmd entry with > a new value. > 4. CPU may hit an exception because the old pmd entry is still in TLB, > which leads to a kernel panic. > > Commit b6bdb7517c3d ("mm/vmalloc: add interfaces to free unmapped page > table") has addressed this panic by falling to pte mappings in the above > case on ARM64. > > To support pmd mappings in all cases, TLB purge needs to be performed > in this case on ARM64. > > Add a new arg, 'addr', to pud_free_pmd_page() and pmd_free_pte_page() > so that TLB purge can be added later in seprate patches. > > [[email protected]: merge changes, rewrite patch description] > Fixes: 28ee90fe6048 ("x86/mm: implement free pmd/pte page interfaces") > Signed-off-by: Chintan Pandya <[email protected]> > Signed-off-by: Toshi Kani <[email protected]> > Cc: Andrew Morton <[email protected]> > Cc: Michal Hocko <[email protected]> > Cc: Thomas Gleixner <[email protected]> > Cc: Ingo Molnar <[email protected]> > Cc: "H. Peter Anvin" <[email protected]> > Cc: Will Deacon <[email protected]> > Cc: Joerg Roedel <[email protected]> > Cc: <[email protected]> > > --- > arch/arm64/mm/mmu.c | 4 ++-- > arch/x86/mm/pgtable.c | 8 +++++--- > include/asm-generic/pgtable.h | 8 ++++---- > lib/ioremap.c | 4 ++-- > 4 files changed, 13 insertions(+), 11 deletions(-)
Reviewed-by: Will Deacon <[email protected]> Thanks, Will
