From: Andy Lutomirski <luto@xxxxxxxxxx> commit 3d44d51bd339766f0178f0cf2e8d048b4a4872aa upstream. 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. Reported-by: Brian Gerst <brgerst@xxxxxxxxx> Signed-off-by: Andy Lutomirski <luto@xxxxxxxxxx> Cc: Andy Lutomirski <luto@xxxxxxxxxxxxxx> Cc: Borislav Petkov <bp@xxxxxxxxx> Cc: Denys Vlasenko <dvlasenk@xxxxxxxxxx> Cc: H. Peter Anvin <hpa@xxxxxxxxx> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: <stable@xxxxxxxxxxxxxxx> # v3.10 and later Fixes: 63bcff2a307b ("x86, smap: Add STAC and CLAC instructions to control user space access") Link: http://lkml.kernel.org/r/b02b7e71ae54074be01fc171cbd4b72517055c0e.1456345086.git.luto@xxxxxxxxxx Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> [ kamal: backport to 3.10 through 3.19-stable: file rename; context ] Signed-off-by: Kamal Mostafa <kamal@xxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sasha.levin@xxxxxxxxxx> --- arch/x86/ia32/ia32entry.S | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/x86/ia32/ia32entry.S b/arch/x86/ia32/ia32entry.S index ffe7122..a39e89e 100644 --- a/arch/x86/ia32/ia32entry.S +++ b/arch/x86/ia32/ia32entry.S @@ -422,6 +422,7 @@ ENTRY(ia32_syscall) /*CFI_REL_OFFSET cs,CS-RIP*/ CFI_REL_OFFSET rip,RIP-RIP PARAVIRT_ADJUST_EXCEPTION_FRAME + ASM_CLAC /* Do this early to minimize exposure */ SWAPGS /* * No need to follow this irqs on/off section: the syscall -- 2.5.0 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html