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author | Song Liu <songliubraving@fb.com> | 2019-08-28 23:54:55 +0200 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-10-05 13:13:51 +0200 |
commit | 07e66eb2a8c00a00fe19efaaf8e3378b443c106f (patch) | |
tree | 74daec339fc28ed031c846792785b49cf4dc7833 /arch | |
parent | 6198f3954f1536b5a053a4ec691e4758cb0501ea (diff) | |
download | linux-stable-07e66eb2a8c00a00fe19efaaf8e3378b443c106f.tar.gz linux-stable-07e66eb2a8c00a00fe19efaaf8e3378b443c106f.tar.bz2 linux-stable-07e66eb2a8c00a00fe19efaaf8e3378b443c106f.zip |
x86/mm/pti: Handle unaligned address gracefully in pti_clone_pagetable()
[ Upstream commit 825d0b73cd7526b0bb186798583fae810091cbac ]
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
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'arch')
-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 ba22b50f4eca..7f2140414440 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; } |