From: Russell King <rmk+kernel@armlinux.org.uk>
Date: Sun, 22 Dec 2019 16:39:40 +0000 (+0000)
Subject: ARM: allow unwinder to unwind recursive functions
X-Git-Tag: v5.10.7~2909^2~6
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=8d54a27593896895f6166a1ac69eac99c8a6a71a;p=platform%2Fkernel%2Flinux-rpi.git

ARM: allow unwinder to unwind recursive functions

Allow the unwinder to unwind recursive functions if the stack makes
progress, even if the PC is the same. This allows tracing through
recursive __switchdev_handle_port_attr_set() and similar.

Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
---

diff --git a/arch/arm/kernel/unwind.c b/arch/arm/kernel/unwind.c
index 4574e6a..11a964f 100644
--- a/arch/arm/kernel/unwind.c
+++ b/arch/arm/kernel/unwind.c
@@ -444,7 +444,7 @@ int unwind_frame(struct stackframe *frame)
 		ctrl.vrs[PC] = ctrl.vrs[LR];
 
 	/* check for infinite loop */
-	if (frame->pc == ctrl.vrs[PC])
+	if (frame->pc == ctrl.vrs[PC] && frame->sp == ctrl.vrs[SP])
 		return -URC_FAILURE;
 
 	frame->fp = ctrl.vrs[FP];