This is a note to let you know that I've just added the patch titled
MIPS: ptrace: Avoid smp_processor_id() when retrieving FPU IR
to the 3.16-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-ptrace-avoid-smp_processor_id-when-retrieving-fpu-ir.patch
and it can be found in the queue-3.16 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 656ff9bef08c19a6471b49528dacb4cbbeb1e537 Mon Sep 17 00:00:00 2001
From: Alex Smith <alex@xxxxxxxxxxxxxxxx>
Date: Wed, 23 Jul 2014 14:40:06 +0100
Subject: MIPS: ptrace: Avoid smp_processor_id() when retrieving FPU IR
From: Alex Smith <alex@xxxxxxxxxxxxxxxx>
commit 656ff9bef08c19a6471b49528dacb4cbbeb1e537 upstream.
Whenever ptrace attempts to retrieve the FPU implementation register it
accesses it through current_cpu_data, which calls smp_processor_id().
Since the code may execute with preemption enabled, this can trigger
a warning. Fix this by using boot_cpu_data to get the IR instead.
Signed-off-by: Alex Smith <alex@xxxxxxxxxxxxxxxx>
Cc: linux-mips@xxxxxxxxxxxxxx
Patchwork: https://patchwork.linux-mips.org/patch/7449/
Signed-off-by: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/mips/kernel/ptrace.c | 4 ++--
arch/mips/kernel/ptrace32.c | 2 +-
2 files changed, 3 insertions(+), 3 deletions(-)
--- a/arch/mips/kernel/ptrace.c
+++ b/arch/mips/kernel/ptrace.c
@@ -129,7 +129,7 @@ int ptrace_getfpregs(struct task_struct
}
__put_user(child->thread.fpu.fcr31, data + 64);
- __put_user(current_cpu_data.fpu_id, data + 65);
+ __put_user(boot_cpu_data.fpu_id, data + 65);
return 0;
}
@@ -611,7 +611,7 @@ long arch_ptrace(struct task_struct *chi
break;
case FPC_EIR:
/* implementation / version register */
- tmp = current_cpu_data.fpu_id;
+ tmp = boot_cpu_data.fpu_id;
break;
case DSP_BASE ... DSP_BASE + 5: {
dspreg_t *dregs;
--- a/arch/mips/kernel/ptrace32.c
+++ b/arch/mips/kernel/ptrace32.c
@@ -129,7 +129,7 @@ long compat_arch_ptrace(struct task_stru
break;
case FPC_EIR:
/* implementation / version register */
- tmp = current_cpu_data.fpu_id;
+ tmp = boot_cpu_data.fpu_id;
break;
case DSP_BASE ... DSP_BASE + 5: {
dspreg_t *dregs;
Patches currently in stable-queue which might be from alex@xxxxxxxxxxxxxxxx are
queue-3.16/mips-ptrace-test-correct-task-s-flags-in-task_user_regset_view.patch
queue-3.16/mips-asm-reg.h-make-32-and-64-bit-definitions-available-at-the-same-time.patch
queue-3.16/mips-ptrace-change-gp-regset-to-use-correct-core-dump-register-layout.patch
queue-3.16/mips-ptrace-avoid-smp_processor_id-when-retrieving-fpu-ir.patch
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