Messages in this thread Patch in this message | | | Date | Thu, 29 Aug 2019 19:02:45 -0000 | From | "tip-bot2 for Song Liu" <> | Subject | [tip: x86/pti] x86/mm/pti: Handle unaligned address gracefully in pti_clone_pagetable() |
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The following commit has been merged into the x86/pti branch of tip:
Commit-ID: 825d0b73cd7526b0bb186798583fae810091cbac Gitweb: https://git.kernel.org/tip/825d0b73cd7526b0bb186798583fae810091cbac Author: Song Liu <songliubraving@fb.com> AuthorDate: Wed, 28 Aug 2019 23:54:55 +02:00 Committer: Thomas Gleixner <tglx@linutronix.de> CommitterDate: Thu, 29 Aug 2019 20:52:52 +02:00
x86/mm/pti: Handle unaligned address gracefully in pti_clone_pagetable()
pti_clone_pmds() assumes that the supplied address is either:
- properly PUD/PMD aligned or - the address is actually mapped which means that independently of the mapping level (PUD/PMD/PTE) the next higher mapping exists.
If that's not the case the unaligned address can be incremented by PUD or PMD size incorrectly. All callers supply mapped and/or aligned addresses, but for the sake of robustness it's better to handle that case properly and to emit a warning.
[ tglx: Rewrote changelog and added WARN_ON_ONCE() ]
Signed-off-by: Song Liu <songliubraving@fb.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Ingo Molnar <mingo@kernel.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/alpine.DEB.2.21.1908282352470.1938@nanos.tec.linutronix.de
--- arch/x86/mm/pti.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/arch/x86/mm/pti.c b/arch/x86/mm/pti.c index b196524..a24487b 100644 --- a/arch/x86/mm/pti.c +++ b/arch/x86/mm/pti.c @@ -330,13 +330,15 @@ pti_clone_pgtable(unsigned long start, unsigned long end, pud = pud_offset(p4d, addr); if (pud_none(*pud)) { - addr += PUD_SIZE; + WARN_ON_ONCE(addr & ~PUD_MASK); + addr = round_up(addr + 1, PUD_SIZE); continue; } pmd = pmd_offset(pud, addr); if (pmd_none(*pmd)) { - addr += PMD_SIZE; + WARN_ON_ONCE(addr & ~PMD_MASK); + addr = round_up(addr + 1, PMD_SIZE); continue; }
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