This is a note to let you know that I've just added the patch titled
dm round robin: do not use this_cpu_ptr() without having preemption disabled
to the 4.7-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:
dm-round-robin-do-not-use-this_cpu_ptr-without-having-preemption-disabled.patch
and it can be found in the queue-4.7 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 802934b2cfde463b72cc1b9bc1c081895a90be53 Mon Sep 17 00:00:00 2001
From: Mike Snitzer <snitzer@xxxxxxxxxx>
Date: Fri, 5 Aug 2016 12:29:06 -0400
Subject: dm round robin: do not use this_cpu_ptr() without having preemption disabled
From: Mike Snitzer <snitzer@xxxxxxxxxx>
commit 802934b2cfde463b72cc1b9bc1c081895a90be53 upstream.
Use local_irq_save() to disable preemption before calling
this_cpu_ptr().
Reported-by: Benjamin Block <bblock@xxxxxxxxxxxxxxxxxx>
Fixes: b0b477c7e0dd ("dm round robin: use percpu 'repeat_count' and 'current_path'")
Suggested-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/md/dm-round-robin.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
--- a/drivers/md/dm-round-robin.c
+++ b/drivers/md/dm-round-robin.c
@@ -210,14 +210,17 @@ static struct dm_path *rr_select_path(st
struct path_info *pi = NULL;
struct dm_path *current_path = NULL;
+ local_irq_save(flags);
current_path = *this_cpu_ptr(s->current_path);
if (current_path) {
percpu_counter_dec(&s->repeat_count);
- if (percpu_counter_read_positive(&s->repeat_count) > 0)
+ if (percpu_counter_read_positive(&s->repeat_count) > 0) {
+ local_irq_restore(flags);
return current_path;
+ }
}
- spin_lock_irqsave(&s->lock, flags);
+ spin_lock(&s->lock);
if (!list_empty(&s->valid_paths)) {
pi = list_entry(s->valid_paths.next, struct path_info, list);
list_move_tail(&pi->list, &s->valid_paths);
Patches currently in stable-queue which might be from snitzer@xxxxxxxxxx are
queue-4.7/dm-round-robin-do-not-use-this_cpu_ptr-without-having-preemption-disabled.patch
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