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FAILED: patch "[PATCH] x86/entry/compat: Add missing CLAC to entry_INT80_32" failed to apply to 3.10-stable tree

PATCH [email protected] 1 participant 1 message Mar 1, 2016

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The patch below does not apply to the 3.10-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

Quoted 1 line

From 3d44d51bd339766f0178f0cf2e8d048b4a4872aa Mon Sep 17 00:00:00 2001

From: Andy Lutomirski <[email protected]>
Date: Wed, 24 Feb 2016 12:18:49 -0800
Subject: [PATCH] x86/entry/compat: Add missing CLAC to entry_INT80_32

This doesn't seem to fix a regression -- I don't think the CLAC was ever there.

I double-checked in a debugger: entries through the int80 gate do not automatically clear AC.

Stable maintainers: I can provide a backport to 4.3 and earlier if needed. This needs to be backported all the way to 3.10.

Cc Andy Lutomirski <[email protected]>
Cc Borislav Petkov <[email protected]>
Cc Denys Vlasenko <[email protected]>
Cc H. Peter Anvin <[email protected]>
Cc Linus Torvalds <[email protected]>
Cc Peter Zijlstra <[email protected]>
Cc Thomas Gleixner <[email protected]>
Cc <[email protected]> # v3.10 and later
Fixes 63bcff2a307b ("x86, smap: Add STAC and CLAC instructions to control user space access")
arch/x86/entry/entry_64_compat.S +1 -0
index ff1c6d61f332..3c990eeee40b 100644
@@ -261,6 +261,7 @@ ENTRY(entry_INT80_compat)
 	 * Interrupts are off on entry.
 	 */
 	PARAVIRT_ADJUST_EXCEPTION_FRAME
+	ASM_CLAC			/* Do this early to minimize exposure */
 	SWAPGS
 
 	/*