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* [PATCH 4.4-stable] kaiser: Set _PAGE_NX only if supported
@ 2018-01-12 21:31 Lepton Wu
  2018-01-12 21:38 ` [PATCH 4.4-stable v2] " Lepton Wu
                   ` (3 more replies)
  0 siblings, 4 replies; 18+ messages in thread
From: Lepton Wu @ 2018-01-12 21:31 UTC (permalink / raw)
  To: stable; +Cc: gregkh, groeck, hshan, Lepton Wu

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

See https://www.spinics.net/lists/kernel/msg2689835.html for details.

Signed-off-by: Lepton Wu <ytht.net@gmail.com>
---
 arch/x86/mm/kaiser.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/x86/mm/kaiser.c b/arch/x86/mm/kaiser.c
index 6a7a77929a8c..936672f71139 100644
--- a/arch/x86/mm/kaiser.c
+++ b/arch/x86/mm/kaiser.c
@@ -198,6 +198,10 @@ 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 CPU doesn't support NX, don't set it. */
+        if (!(__supported_pte_mask & _PAGE_NX))
+		flags &= ~_PAGE_NX;
+
 
 	for (; address < end_addr; address += PAGE_SIZE) {
 		target_address = get_pa_from_mapping(address);
-- 
2.16.0.rc1.238.g530d649a79-goog

^ permalink raw reply related	[flat|nested] 18+ messages in thread

end of thread, other threads:[~2018-02-05 19:26 UTC | newest]

Thread overview: 18+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2018-01-12 21:31 [PATCH 4.4-stable] kaiser: Set _PAGE_NX only if supported Lepton Wu
2018-01-12 21:38 ` [PATCH 4.4-stable v2] " Lepton Wu
2018-01-12 21:39 ` [PATCH 4.4-stable] " Guenter Roeck
2018-01-12 21:41 ` [PATCH 4.4-stable v3] " Lepton Wu
2018-01-12 21:46   ` Guenter Roeck
2018-01-12 21:48     ` lepton
2018-01-12 23:05       ` lepton
2018-01-13 14:51         ` Greg Kroah-Hartman
2018-01-13 18:47           ` lepton
2018-01-13 19:10             ` Greg Kroah-Hartman
2018-01-16 14:18             ` [PATCH 3.2-stable 1/2] " Juerg Haefliger
2018-01-16 14:18             ` [PATCH 3.2-stable 2/2] " Juerg Haefliger
2018-01-16 14:19             ` [PATCH 3.16-stable 1/2] " Juerg Haefliger
2018-02-05 19:26               ` Ben Hutchings
2018-01-16 14:19             ` [PATCH 3.16-stable 2/2] " Juerg Haefliger
2018-01-12 21:42 ` [PATCH 4.4-stable v4] " Lepton Wu
2018-01-13 14:53   ` Patch "kaiser: Set _PAGE_NX only if supported" has been added to the 4.4-stable tree gregkh
2018-01-13 14:53   ` Patch "kaiser: Set _PAGE_NX only if supported" has been added to the 4.9-stable tree gregkh

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