This is a note to let you know that I have just added a patch titled
MIPS: lib: Mark intrinsics notrace
to the linux-4.2.y-queue branch of the 4.2.y-ckt extended stable tree
which can be found at:
https://git.launchpad.net/~canonical-kernel/linux/+git/linux-stable-ckt/log/?h=linux-4.2.y-queue
This patch is scheduled to be released in version 4.2.8-ckt12.
If you, or anyone else, feels it should not be added to this tree, please
reply to this email.
For more information about the 4.2.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable
Thanks.
-Kamal
---8<------------------------------------------------------------
>From 41bab06c988f506c4dee786f7ee925bd437ecf56 Mon Sep 17 00:00:00 2001
From: Harvey Hunt <harvey.hunt@xxxxxxxxxx>
Date: Wed, 25 May 2016 11:06:35 +0100
Subject: MIPS: lib: Mark intrinsics notrace
commit aedcfbe06558a9f53002e82d5be64c6c94687726 upstream.
On certain MIPS32 devices, the ftrace tracer "function_graph" uses
__lshrdi3() during the capturing of trace data. ftrace then attempts to
trace __lshrdi3() which leads to infinite recursion and a stack overflow.
Fix this by marking __lshrdi3() as notrace. Mark the other compiler
intrinsics as notrace in case the compiler decides to use them in the
ftrace path.
Signed-off-by: Harvey Hunt <harvey.hunt@xxxxxxxxxx>
Cc: <linux-mips@xxxxxxxxxxxxxx>
Cc: <linux-kernel@xxxxxxxxxxxxxxx>
Patchwork: https://patchwork.linux-mips.org/patch/13354/
Signed-off-by: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
[ kamal: backport to 4.2-stable: no bswap[ds]i.c ]
Signed-off-by: Kamal Mostafa <kamal@xxxxxxxxxxxxx>
---
arch/mips/lib/ashldi3.c | 2 +-
arch/mips/lib/ashrdi3.c | 2 +-
arch/mips/lib/cmpdi2.c | 2 +-
arch/mips/lib/lshrdi3.c | 2 +-
arch/mips/lib/ucmpdi2.c | 2 +-
5 files changed, 5 insertions(+), 5 deletions(-)
diff --git a/arch/mips/lib/ashldi3.c b/arch/mips/lib/ashldi3.c
index beb80f31..927dc94 100644
--- a/arch/mips/lib/ashldi3.c
+++ b/arch/mips/lib/ashldi3.c
@@ -2,7 +2,7 @@
#include "libgcc.h"
-long long __ashldi3(long long u, word_type b)
+long long notrace __ashldi3(long long u, word_type b)
{
DWunion uu, w;
word_type bm;
diff --git a/arch/mips/lib/ashrdi3.c b/arch/mips/lib/ashrdi3.c
index c884a91..9fdf1a5 100644
--- a/arch/mips/lib/ashrdi3.c
+++ b/arch/mips/lib/ashrdi3.c
@@ -2,7 +2,7 @@
#include "libgcc.h"
-long long __ashrdi3(long long u, word_type b)
+long long notrace __ashrdi3(long long u, word_type b)
{
DWunion uu, w;
word_type bm;
diff --git a/arch/mips/lib/cmpdi2.c b/arch/mips/lib/cmpdi2.c
index 8c13064..06857da 100644
--- a/arch/mips/lib/cmpdi2.c
+++ b/arch/mips/lib/cmpdi2.c
@@ -2,7 +2,7 @@
#include "libgcc.h"
-word_type __cmpdi2(long long a, long long b)
+word_type notrace __cmpdi2(long long a, long long b)
{
const DWunion au = {
.ll = a
diff --git a/arch/mips/lib/lshrdi3.c b/arch/mips/lib/lshrdi3.c
index dcf8d68..3645474 100644
--- a/arch/mips/lib/lshrdi3.c
+++ b/arch/mips/lib/lshrdi3.c
@@ -2,7 +2,7 @@
#include "libgcc.h"
-long long __lshrdi3(long long u, word_type b)
+long long notrace __lshrdi3(long long u, word_type b)
{
DWunion uu, w;
word_type bm;
diff --git a/arch/mips/lib/ucmpdi2.c b/arch/mips/lib/ucmpdi2.c
index bb4cb2f..bd599f5 100644
--- a/arch/mips/lib/ucmpdi2.c
+++ b/arch/mips/lib/ucmpdi2.c
@@ -2,7 +2,7 @@
#include "libgcc.h"
-word_type __ucmpdi2(unsigned long long a, unsigned long long b)
+word_type notrace __ucmpdi2(unsigned long long a, unsigned long long b)
{
const DWunion au = {.ll = a};
const DWunion bu = {.ll = b};
--
2.7.4
