This is a note to let you know that I've just added the patch titled
kaiser: Set _PAGE_NX only if supported
to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...
The filename of the patch is: kaiser-set-_page_nx-only-if-supported.patch and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.
From ytht.net@gmail.com Sat Jan 13 15:46:36 2018
From: Lepton Wu ytht.net@gmail.com Date: Fri, 12 Jan 2018 13:42:56 -0800 Subject: kaiser: Set _PAGE_NX only if supported To: stable@vger.kernel.org Cc: gregkh@linuxfoundation.org, groeck@chromium.org, hshan@google.com, Lepton Wu ytht.net@gmail.com Message-ID: 20180112214256.257463-1-ytht.net@gmail.com
From: Lepton Wu ytht.net@gmail.com
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 --- arch/x86/mm/kaiser.c | 2 ++ 1 file changed, 2 insertions(+)
--- a/arch/x86/mm/kaiser.c +++ b/arch/x86/mm/kaiser.c @@ -198,6 +198,8 @@ static int kaiser_add_user_map(const voi * 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;
for (; address < end_addr; address += PAGE_SIZE) { target_address = get_pa_from_mapping(address);
Patches currently in stable-queue which might be from ytht.net@gmail.com are
queue-4.4/kaiser-set-_page_nx-only-if-supported.patch