[3.19.y-ckt stable] Patch "s390/stacktrace: fix address ranges for asynchronous and panic stack" has been added to the 3.19.y-ckt tree

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    s390/stacktrace: fix address ranges for asynchronous and panic stack

to the linux-3.19.y-queue branch of the 3.19.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.19.y-queue

This patch is scheduled to be released in version 3.19.8-ckt16.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.19.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

---8<------------------------------------------------------------

>From e1fffd1c0388fe4f6a39d5bb4f958bb902afd676 Mon Sep 17 00:00:00 2001
From: Heiko Carstens <heiko.carstens at de.ibm.com>
Date: Mon, 1 Feb 2016 10:13:05 +0100
Subject: s390/stacktrace: fix address ranges for asynchronous and panic stack

commit 9900c48c46d8bcf497972024c5fe366e6d9771f3 upstream.

git commit dc7ee00d4771 ("s390: lowcore stack pointer offsets")
introduced a regression in regard to save_stack_trace(). The stack
pointer for the asynchronous and the panic stack in the lowcore now
have an additional offset applied to them. This offset needs to be
taken into account in the calculation for the low and high address for
the stacks.

This bug was already partially fixed with 9cc5c206d9b4
("s390/dumpstack: fix address ranges for asynchronous and panic
stack"). This patch fixes it also for the stacktrace code.

Fixes: dc7ee00d4771 ("s390: lowcore stack pointer offsets")
Signed-off-by: Heiko Carstens <heiko.carstens at de.ibm.com>
Tested-by: Peter Oberparleiter <oberpar at linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky at de.ibm.com>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 arch/s390/kernel/stacktrace.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/arch/s390/kernel/stacktrace.c b/arch/s390/kernel/stacktrace.c
index 1785cd8..8be2c35 100644
--- a/arch/s390/kernel/stacktrace.c
+++ b/arch/s390/kernel/stacktrace.c
@@ -63,17 +63,18 @@ static unsigned long save_context_stack(struct stack_trace *trace,
 void save_stack_trace(struct stack_trace *trace)
 {
 	register unsigned long sp asm ("15");
-	unsigned long orig_sp, new_sp;
+	unsigned long orig_sp, new_sp, frame_size;

+	frame_size = STACK_FRAME_OVERHEAD + sizeof(struct pt_regs);
 	orig_sp = sp & PSW_ADDR_INSN;
 	new_sp = save_context_stack(trace, orig_sp,
-				    S390_lowcore.panic_stack - PAGE_SIZE,
-				    S390_lowcore.panic_stack, 1);
+			S390_lowcore.panic_stack + frame_size - PAGE_SIZE,
+			S390_lowcore.panic_stack + frame_size, 1);
 	if (new_sp != orig_sp)
 		return;
 	new_sp = save_context_stack(trace, new_sp,
-				    S390_lowcore.async_stack - ASYNC_SIZE,
-				    S390_lowcore.async_stack, 1);
+			S390_lowcore.async_stack + frame_size - ASYNC_SIZE,
+			S390_lowcore.async_stack + frame_size, 1);
 	if (new_sp != orig_sp)
 		return;
 	save_context_stack(trace, new_sp,
--
2.7.0