On 16.08.21 09:46, qiang.zhang@xxxxxxxxxxxxx wrote:
From: "Qiang.Zhang" <qiang.zhang@xxxxxxxxxxxxx>
The flush_all_cpus_locked() should be called with cpus_read_lock/unlock(),
ensure flush_cpu_slab() can be executed on schedule_on CPU.
Fixes: 1c84f3c91640 ("mm, slub: fix memory and cpu hotplug related lock ordering issues")
Which branch contains this commit? At least not linux.git or linux-next
Signed-off-by: Qiang.Zhang <qiang.zhang@xxxxxxxxxxxxx>
---
mm/slub.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/mm/slub.c b/mm/slub.c
index 5543d57cb128..cf3f93abbd3e 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -4593,12 +4593,14 @@ static int slab_mem_going_offline_callback(void *arg)
{
struct kmem_cache *s;
+ cpus_read_lock();
mutex_lock(&slab_mutex);
list_for_each_entry(s, &slab_caches, list) {
flush_all_cpus_locked(s);
__kmem_cache_do_shrink(s);
}
mutex_unlock(&slab_mutex);
+ cpus_read_unlock();
return 0;
}
Memory notifiers are getting called from online_pages()/offline_pages(),
where we call memory_notify(MEM_GOING_OFFLINE, &arg) under
mem_hotplug_begin().
mem_hotplug_begin() does a cpus_read_lock().
How does this even work or against which branch is this?
--
Thanks,
David / dhildenb
