From mboxrd@z Thu Jan 1 00:00:00 1970 From: ard.biesheuvel@linaro.org (Ard Biesheuvel) Date: Wed, 7 Nov 2018 11:36:19 +0100 Subject: [PATCH v4 1/2] arm64: mm: purge lazily unmapped vm regions before changing permissions In-Reply-To: <20181107103620.16054-1-ard.biesheuvel@linaro.org> References: <20181107103620.16054-1-ard.biesheuvel@linaro.org> Message-ID: <20181107103620.16054-2-ard.biesheuvel@linaro.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Call vm_unmap_aliases() every time we apply any changes to permission attributes of mappings in the vmalloc region. This avoids any potential issues resulting from lingering writable or executable aliases of mappings that should be read-only or non-executable, respectively. Acked-by: Will Deacon Signed-off-by: Ard Biesheuvel --- arch/arm64/mm/pageattr.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/arch/arm64/mm/pageattr.c b/arch/arm64/mm/pageattr.c index a56359373d8b..787f9e385e6d 100644 --- a/arch/arm64/mm/pageattr.c +++ b/arch/arm64/mm/pageattr.c @@ -93,6 +93,12 @@ static int change_memory_common(unsigned long addr, int numpages, if (!numpages) return 0; + /* + * Get rid of potentially aliasing lazily unmapped vm areas that may + * have permissions set that deviate from the ones we are setting here. + */ + vm_unmap_aliases(); + return __change_memory_common(start, size, set_mask, clear_mask); } -- 2.19.1