From: Max Filippov <jcmvbkbc@gmail.com>
Date: Wed, 2 Jan 2019 09:08:32 +0000 (-0800)
Subject: xtensa: fix get_wchan
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=d90b88fd3653f1fb66ecc6571b860d5a5749fa56;p=linux.git

xtensa: fix get_wchan

Stack unwinding is implemented incorrectly in xtensa get_wchan: instead
of extracting a0 and a1 registers from the spill location under the
stack pointer it extracts a word pointed to by the stack pointer and
subtracts 4 or 3 from it.

Cc: stable@vger.kernel.org
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
---

diff --git a/arch/xtensa/kernel/process.c b/arch/xtensa/kernel/process.c
index 74969a437a37c..2e73395f0560c 100644
--- a/arch/xtensa/kernel/process.c
+++ b/arch/xtensa/kernel/process.c
@@ -321,8 +321,8 @@ unsigned long get_wchan(struct task_struct *p)
 
 		/* Stack layout: sp-4: ra, sp-3: sp' */
 
-		pc = MAKE_PC_FROM_RA(*(unsigned long*)sp - 4, sp);
-		sp = *(unsigned long *)sp - 3;
+		pc = MAKE_PC_FROM_RA(SPILL_SLOT(sp, 0), sp);
+		sp = SPILL_SLOT(sp, 1);
 	} while (count++ < 16);
 	return 0;
 }