x86/entry: Fix idtentry unwind hint

This fixes the following ORC warning in the 'int3' entry code:

  WARNING: can't dereference iret registers at ffff8801c5f17fe0 for ip ffffffff95f0d94b

The ORC metadata had the wrong stack offset for the iret registers.

Their location on the stack is dependent on whether the exception has an
error code.

Reported-and-tested-by: Andrei Vagin <[email protected]>
Signed-off-by: Josh Poimboeuf <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Fixes: 8c1f75587a18 ("x86/entry/64: Add unwind hint annotations")
Link: http://lkml.kernel.org/r/931d57f0551ed7979d5e7e05370d445c8e5137f8.1508516398.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <[email protected]>

diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index 49167258d587570673c5e515cb00b4d8f26263b7..f6cdb7a1455e82cce2c568e2add3564835a5352f 100644 (file)
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -808,7 +808,7 @@ apicinterrupt IRQ_WORK_VECTOR                       irq_work_interrupt              smp_irq_work_interrupt
 
 .macro idtentry sym do_sym has_error_code:req paranoid=0 shift_ist=-1
 ENTRY(\sym)
-       UNWIND_HINT_IRET_REGS offset=8
+       UNWIND_HINT_IRET_REGS offset=\has_error_code*8
 
        /* Sanity check */
        .if \shift_ist != -1 && \paranoid == 0