[PATCH 5.6 100/118] x86/entry/64: Fix unwind hints in rewind_stack_do_exit()

From: Greg Kroah-Hartman
Date: Wed May 13 2020 - 05:55:35 EST


From: Jann Horn <jannh@xxxxxxxxxx>

commit f977df7b7ca45a4ac4b66d30a8931d0434c394b1 upstream.

The LEAQ instruction in rewind_stack_do_exit() moves the stack pointer
directly below the pt_regs at the top of the task stack before calling
do_exit(). Tell the unwinder to expect pt_regs.

Fixes: 8c1f75587a18 ("x86/entry/64: Add unwind hint annotations")
Reviewed-by: Miroslav Benes <mbenes@xxxxxxx>
Signed-off-by: Jann Horn <jannh@xxxxxxxxxx>
Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Dave Jones <dsj@xxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Vince Weaver <vincent.weaver@xxxxxxxxx>
Link: https://lore.kernel.org/r/68c33e17ae5963854916a46f522624f8e1d264f2.1587808742.git.jpoimboe@xxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
arch/x86/entry/entry_64.S | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -1739,7 +1739,7 @@ SYM_CODE_START(rewind_stack_do_exit)

movq PER_CPU_VAR(cpu_current_top_of_stack), %rax
leaq -PTREGS_SIZE(%rax), %rsp
- UNWIND_HINT_FUNC sp_offset=PTREGS_SIZE
+ UNWIND_HINT_REGS

call do_exit
SYM_CODE_END(rewind_stack_do_exit)