From: Ard Biesheuvel Date: Wed, 7 Nov 2018 10:36:19 +0000 (+0100) Subject: arm64: mm: purge lazily unmapped vm regions before changing permissions X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=b34d2ef0c60e4d9c2bb8a4d72d4519c67363d390;p=linux.git arm64: mm: purge lazily unmapped vm regions before changing permissions 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. Signed-off-by: Ard Biesheuvel Signed-off-by: Will Deacon --- diff --git a/arch/arm64/mm/pageattr.c b/arch/arm64/mm/pageattr.c index a56359373d8b3..787f9e385e6da 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); }