diff options
Diffstat (limited to 'debian/patches-rt/0327-mm-slub-Always-flush-the-delayed-empty-slubs-in-flus.patch')
| -rw-r--r-- | debian/patches-rt/0327-mm-slub-Always-flush-the-delayed-empty-slubs-in-flus.patch | 64 |
1 files changed, 64 insertions, 0 deletions
diff --git a/debian/patches-rt/0327-mm-slub-Always-flush-the-delayed-empty-slubs-in-flus.patch b/debian/patches-rt/0327-mm-slub-Always-flush-the-delayed-empty-slubs-in-flus.patch new file mode 100644 index 000000000..870ba009b --- /dev/null +++ b/debian/patches-rt/0327-mm-slub-Always-flush-the-delayed-empty-slubs-in-flus.patch @@ -0,0 +1,64 @@ +From b997a51c5b5970f8defda681658e94bb5612dd2f Mon Sep 17 00:00:00 2001 +From: Kevin Hao <haokexin@gmail.com> +Date: Mon, 4 May 2020 11:34:07 +0800 +Subject: [PATCH 327/347] mm: slub: Always flush the delayed empty slubs in + flush_all() +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.19/older/patches-4.19.246-rt110.tar.xz + +[ Upstream commit 23a2c31b19e99beaf5107071b0f32a596202cdae ] + +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 <haokexin@gmail.com> +Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> +Cc: stable-rt@vger.kernel.org +Signed-off-by: Tom Zanussi <zanussi@kernel.org> +--- + mm/slub.c | 3 --- + 1 file changed, 3 deletions(-) + +diff --git a/mm/slub.c b/mm/slub.c +index 3b1edb545215..497096152c39 100644 +--- a/mm/slub.c ++++ b/mm/slub.c +@@ -2376,9 +2376,6 @@ 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); +-- +2.36.1 + |