This is a note to let you know that I've just added the patch titled
MIPS: Call dump_stack() from show_regs()
to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
mips-call-dump_stack-from-show_regs.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 5a267832c2ec47b2dad0fdb291a96bb5b8869315 Mon Sep 17 00:00:00 2001
From: Paul Burton <paul.burton@xxxxxxxx>
Date: Fri, 22 Jun 2018 10:55:45 -0700
Subject: MIPS: Call dump_stack() from show_regs()
From: Paul Burton <paul.burton@xxxxxxxx>
commit 5a267832c2ec47b2dad0fdb291a96bb5b8869315 upstream.
The generic nmi_cpu_backtrace() function calls show_regs() when a struct
pt_regs is available, and dump_stack() otherwise. If we were to make use
of the generic nmi_cpu_backtrace() with MIPS' current implementation of
show_regs() this would mean that we see only register data with no
accompanying stack information, in contrast with our current
implementation which calls dump_stack() regardless of whether register
state is available.
In preparation for making use of the generic nmi_cpu_backtrace() to
implement arch_trigger_cpumask_backtrace(), have our implementation of
show_regs() call dump_stack() and drop the explicit dump_stack() call in
arch_dump_stack() which is invoked by arch_trigger_cpumask_backtrace().
This will allow the output we produce to remain the same after a later
patch switches to using nmi_cpu_backtrace(). It may mean that we produce
extra stack output in other uses of show_regs(), but this:
1) Seems harmless.
2) Is good for consistency between arch_trigger_cpumask_backtrace()
and other users of show_regs().
3) Matches the behaviour of the ARM & PowerPC architectures.
Marked for stable back to v4.9 as a prerequisite of the following patch
"MIPS: Call dump_stack() from show_regs()".
Signed-off-by: Paul Burton <paul.burton@xxxxxxxx>
Patchwork: https://patchwork.linux-mips.org/patch/19596/
Cc: James Hogan <jhogan@xxxxxxxxxx>
Cc: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
Cc: Huacai Chen <chenhc@xxxxxxxxxx>
Cc: linux-mips@xxxxxxxxxxxxxx
Cc: stable@xxxxxxxxxxxxxxx # v4.9+
Signed-off-by: Huacai Chen <chenhc@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/mips/kernel/process.c | 4 ++--
arch/mips/kernel/traps.c | 1 +
2 files changed, 3 insertions(+), 2 deletions(-)
--- a/arch/mips/kernel/process.c
+++ b/arch/mips/kernel/process.c
@@ -637,8 +637,8 @@ static void arch_dump_stack(void *info)
if (regs)
show_regs(regs);
-
- dump_stack();
+ else
+ dump_stack();
}
void arch_trigger_all_cpu_backtrace(bool include_self)
--- a/arch/mips/kernel/traps.c
+++ b/arch/mips/kernel/traps.c
@@ -344,6 +344,7 @@ static void __show_regs(const struct pt_
void show_regs(struct pt_regs *regs)
{
__show_regs((struct pt_regs *)regs);
+ dump_stack();
}
void show_registers(struct pt_regs *regs)
Patches currently in stable-queue which might be from paul.burton@xxxxxxxx are
queue-4.4/mips-call-dump_stack-from-show_regs.patch
queue-4.4/mips-use-async-ipis-for-arch_trigger_cpumask_backtrace.patch
