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authorMaurizio Lombardi <mlombard@redhat.com>2022-09-19 19:39:29 +0300
committerVlastimil Babka <vbabka@suse.cz>2022-09-22 22:48:48 +0300
commite45cc288724f0cfd497bb5920bcfa60caa335729 (patch)
treef2a5ea916384456f0abe631828ba35f90f1e18be /mm
parentd71608a877362becdc94191f190902fac1e64d35 (diff)
downloadlinux-e45cc288724f0cfd497bb5920bcfa60caa335729.tar.xz
mm: slub: fix flush_cpu_slab()/__free_slab() invocations in task context.
Commit 5a836bf6b09f ("mm: slub: move flush_cpu_slab() invocations __free_slab() invocations out of IRQ context") moved all flush_cpu_slab() invocations to the global workqueue to avoid a problem related with deactivate_slab()/__free_slab() being called from an IRQ context on PREEMPT_RT kernels. When the flush_all_cpu_locked() function is called from a task context it may happen that a workqueue with WQ_MEM_RECLAIM bit set ends up flushing the global workqueue, this will cause a dependency issue. workqueue: WQ_MEM_RECLAIM nvme-delete-wq:nvme_delete_ctrl_work [nvme_core] is flushing !WQ_MEM_RECLAIM events:flush_cpu_slab WARNING: CPU: 37 PID: 410 at kernel/workqueue.c:2637 check_flush_dependency+0x10a/0x120 Workqueue: nvme-delete-wq nvme_delete_ctrl_work [nvme_core] RIP: 0010:check_flush_dependency+0x10a/0x120[ 453.262125] Call Trace: __flush_work.isra.0+0xbf/0x220 ? __queue_work+0x1dc/0x420 flush_all_cpus_locked+0xfb/0x120 __kmem_cache_shutdown+0x2b/0x320 kmem_cache_destroy+0x49/0x100 bioset_exit+0x143/0x190 blk_release_queue+0xb9/0x100 kobject_cleanup+0x37/0x130 nvme_fc_ctrl_free+0xc6/0x150 [nvme_fc] nvme_free_ctrl+0x1ac/0x2b0 [nvme_core] Fix this bug by creating a workqueue for the flush operation with the WQ_MEM_RECLAIM bit set. Fixes: 5a836bf6b09f ("mm: slub: move flush_cpu_slab() invocations __free_slab() invocations out of IRQ context") Cc: <stable@vger.kernel.org> Signed-off-by: Maurizio Lombardi <mlombard@redhat.com> Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Diffstat (limited to 'mm')
-rw-r--r--mm/slub.c9
1 files changed, 8 insertions, 1 deletions
diff --git a/mm/slub.c b/mm/slub.c
index 5ba6db62a5ab..4b98dff9be8e 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -310,6 +310,11 @@ static inline void stat(const struct kmem_cache *s, enum stat_item si)
*/
static nodemask_t slab_nodes;
+/*
+ * Workqueue used for flush_cpu_slab().
+ */
+static struct workqueue_struct *flushwq;
+
/********************************************************************
* Core slab cache functions
*******************************************************************/
@@ -2730,7 +2735,7 @@ static void flush_all_cpus_locked(struct kmem_cache *s)
INIT_WORK(&sfw->work, flush_cpu_slab);
sfw->skip = false;
sfw->s = s;
- schedule_work_on(cpu, &sfw->work);
+ queue_work_on(cpu, flushwq, &sfw->work);
}
for_each_online_cpu(cpu) {
@@ -4858,6 +4863,8 @@ void __init kmem_cache_init(void)
void __init kmem_cache_init_late(void)
{
+ flushwq = alloc_workqueue("slub_flushwq", WQ_MEM_RECLAIM, 0);
+ WARN_ON(!flushwq);
}
struct kmem_cache *