diff options
| author | Song Liu <songliubraving@fb.com> | 2019-08-28 23:54:55 +0200 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2019-08-29 20:52:52 +0200 |
| commit | 825d0b73cd7526b0bb186798583fae810091cbac (patch) | |
| tree | 4bf50b03cc2e6598ba585f19bc8ce5cdd1d36945 /arch/x86/mm | |
| parent | Linux 5.3-rc6 (diff) | |
| download | linux-825d0b73cd7526b0bb186798583fae810091cbac.tar.xz linux-825d0b73cd7526b0bb186798583fae810091cbac.zip | |
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
Diffstat (limited to 'arch/x86/mm')
| -rw-r--r-- | arch/x86/mm/pti.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/arch/x86/mm/pti.c b/arch/x86/mm/pti.c index b196524759ec..a24487bbc2c4 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; } |