Messages in this thread Patch in this message | | | From | Song Liu <> | Subject | [PATCH] x86/mm/pti: Handle unaligned addr to PMD-mapped page in pti_clone_pgtable | Date | Wed, 18 Sep 2019 22:53:12 -0700 |
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To clone page table of PMD-mapped pages, pti_clone_pgtable() requires PMD aligned start address. [1] adds warning for unaligned addresses. However, there is still no warning for unaligned address to valid huge pmd [2].
Add alignment check in valid pmd_large() case. If the address is unaligned, round it down to the nearest PMD aligned address and show warning.
[1] commit 825d0b73cd75 ("x86/mm/pti: Handle unaligned address gracefully in pti_clone_pagetable()") [2] https://lore.kernel.org/lkml/156864062019.3407.14798418565580024723.tglx@nanos.tec.linutronix.de/
Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@kernel.org> Cc: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Song Liu <songliubraving@fb.com> --- arch/x86/mm/pti.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/arch/x86/mm/pti.c b/arch/x86/mm/pti.c index 7f2140414440..d224115c350d 100644 --- a/arch/x86/mm/pti.c +++ b/arch/x86/mm/pti.c @@ -343,6 +343,10 @@ pti_clone_pgtable(unsigned long start, unsigned long end, } if (pmd_large(*pmd) || level == PTI_CLONE_PMD) { + /* warn and round_down() unaligned addr */ + if (WARN_ON_ONCE(addr & ~PMD_MASK)) + addr &= PMD_MASK; + target_pmd = pti_user_pagetable_walk_pmd(addr); if (WARN_ON(!target_pmd)) return; -- 2.17.1
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