commit 23a2c31b19e99beaf5107071b0f32a596202cdae from
git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git
After commit f0b231101c94 ("mm/SLUB: delay giving back empty slubs to
IRQ enabled regions"), when the free_slab() is invoked with the IRQ
disabled, the empty slubs are moved to a per-CPU list and will be
freed after IRQ enabled later. But in the current codes, there is
a check to see if there really has the cpu slub on a specific cpu
before flushing the delayed empty slubs, this may cause a reference
of already released kmem_cache in a scenario like below:
cpu 0 cpu 1
kmem_cache_destroy()
flush_all()
--->IPI flush_cpu_slab()
flush_slab()
deactivate_slab()
discard_slab()
free_slab()
c->page = NULL;
for_each_online_cpu(cpu)
if (!has_cpu_slab(1, s))
continue
this skip to flush the delayed
empty slub released by cpu1
kmem_cache_free(kmem_cache, s)
kmalloc()
__slab_alloc()
free_delayed()
__free_slab()
reference to released kmem_cache
Fixes: f0b231101c94 ("mm/SLUB: delay giving back empty slubs to IRQ enabled
regions")
Signed-off-by: Kevin Hao <[email protected]>
Signed-off-by: Sebastian Andrzej Siewior <[email protected]>
Cc: [email protected]
---
Hi Bruce,
Please help me merge this into the following two branches:
v5.2/standard/preempt-rt/base
v5.4/standard/preempt-rt/base
mm/slub.c | 3 ---
1 file changed, 3 deletions(-)
diff --git a/mm/slub.c b/mm/slub.c
index 05f176aa7f70..5c10491cd93a 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -2382,9 +2382,6 @@ static void flush_all(struct kmem_cache *s)
for_each_online_cpu(cpu) {
struct slub_free_list *f;
- if (!has_cpu_slab(cpu, s))
- continue;
-
f = &per_cpu(slub_free_list, cpu);
raw_spin_lock_irq(&f->lock);
list_splice_init(&f->list, &tofree);
--
2.26.2
-=-=-=-=-=-=-=-=-=-=-=-
Links: You receive all messages sent to this group.
View/Reply Online (#8719):
https://lists.yoctoproject.org/g/linux-yocto/message/8719
Mute This Topic: https://lists.yoctoproject.org/mt/74470908/21656
Group Owner: [email protected]
Unsubscribe: https://lists.yoctoproject.org/g/linux-yocto/unsub
[[email protected]]
-=-=-=-=-=-=-=-=-=-=-=-
