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authorLepton Wu <ytht.net@gmail.com>2018-01-16 15:19:14 +0100
committerBen Hutchings <ben@decadent.org.uk>2018-02-13 18:32:24 +0000
commitd663ef5a8632389b31c629ac14485ca6f50a7f5e (patch)
parent6d86843a11140f0816f3aeeeb01495e0f8e17b12 (diff)
kaiser: Set _PAGE_NX only if supported
This finally resolve crash if loaded under qemu + haxm. Haitao Shan pointed out that the reason of that crash is that NX bit get set for page tables. It seems we missed checking if _PAGE_NX is supported in kaiser_add_user_map Link: https://www.spinics.net/lists/kernel/msg2689835.html Reviewed-by: Guenter Roeck <groeck@chromium.org> Signed-off-by: Lepton Wu <ytht.net@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> (backported from Greg K-H's 4.4 stable-queue) Signed-off-by: Juerg Haefliger <juerg.haefliger@canonical.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/x86/mm/kaiser.c b/arch/x86/mm/kaiser.c
index 8c95caecd330..b6c645ec4906 100644
--- a/arch/x86/mm/kaiser.c
+++ b/arch/x86/mm/kaiser.c
@@ -189,6 +189,8 @@ static int kaiser_add_user_map(const void *__start_addr, unsigned long size,
* requires that not to be #defined to 0): so mask it off here.
flags &= ~_PAGE_GLOBAL;
+ if (!(__supported_pte_mask & _PAGE_NX))
+ flags &= ~_PAGE_NX;
if (flags & _PAGE_USER)
BUG_ON(address < FIXADDR_START || end_addr >= FIXADDR_TOP);