[PATCH bpf v2 1/4] ARM: unwind: Initialize the lr_addr field of unwind_ctrl_block

[Masami Hiramatsu]

Since the unwind_ctrl_block::lr_addr is finally passed to
stackframe::lr_addr, that value will be exposed unconditionally.
Thus it should be initialized.

Without this fix, when unwind_frame() doesn't update the
unwind_ctrl_block::lr_addr (e.g. 'lr' register is not saved in the
target function), stackframe::lr_addr will contain a wrong value.

Signed-off-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
---
  Changes in v2:
   - Initialize pointer by NULL instead of 0.
---
 arch/arm/kernel/unwind.c |    1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/arm/kernel/unwind.c b/arch/arm/kernel/unwind.c
index a37ea6c772cd..c9f719e1b350 100644
--- a/arch/arm/kernel/unwind.c
+++ b/arch/arm/kernel/unwind.c
@@ -404,6 +404,7 @@ int unwind_frame(struct stackframe *frame)
 	ctrl.vrs[SP] = frame->sp;
 	ctrl.vrs[LR] = frame->lr;
 	ctrl.vrs[PC] = 0;
+	ctrl.lr_addr = NULL;
 
 	if (idx->insn == 1)
 		/* can't unwind */