Patch "MIPS: Fix sched_getaffinity with MT FPAFF enabled" has been added to the 4.1-stable tree

Patch "MIPS: Fix sched_getaffinity with MT FPAFF enabled" has been added to the 4.1-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    MIPS: Fix sched_getaffinity with MT FPAFF enabled

to the 4.1-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-fix-sched_getaffinity-with-mt-fpaff-enabled.patch
and it can be found in the queue-4.1 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 1d62d737555e1378eb62a8bba26644f7d97139d2 Mon Sep 17 00:00:00 2001
From: Felix Fietkau <nbd@openwrt.org>
Date: Sun, 19 Jul 2015 00:38:41 +0200
Subject: MIPS: Fix sched_getaffinity with MT FPAFF enabled

From: Felix Fietkau <nbd@openwrt.org>

commit 1d62d737555e1378eb62a8bba26644f7d97139d2 upstream.

p->thread.user_cpus_allowed is zero-initialized and is only filled on
the first sched_setaffinity call.

To avoid adding overhead in the task initialization codepath, simply OR
the returned mask in sched_getaffinity with p->cpus_allowed.

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10740/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/mips/kernel/mips-mt-fpaff.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

--- a/arch/mips/kernel/mips-mt-fpaff.c
+++ b/arch/mips/kernel/mips-mt-fpaff.c
@@ -154,7 +154,7 @@ asmlinkage long mipsmt_sys_sched_getaffi
 				      unsigned long __user *user_mask_ptr)
 {
 	unsigned int real_len;
-	cpumask_t mask;
+	cpumask_t allowed, mask;
 	int retval;
 	struct task_struct *p;
 
@@ -173,7 +173,8 @@ asmlinkage long mipsmt_sys_sched_getaffi
 	if (retval)
 		goto out_unlock;
 
-	cpumask_and(&mask, &p->thread.user_cpus_allowed, cpu_possible_mask);
+	cpumask_or(&allowed, &p->thread.user_cpus_allowed, &p->cpus_allowed);
+	cpumask_and(&mask, &allowed, cpu_active_mask);
 
 out_unlock:
 	read_unlock(&tasklist_lock);


Patches currently in stable-queue which might be from nbd@openwrt.org are

queue-4.1/mips-export-get_c0_perfcount_int.patch
queue-4.1/mips-fix-sched_getaffinity-with-mt-fpaff-enabled.patch