From: Vlastimil Babka <vbabka@xxxxxxx> Subject: mm, slub: check new pages with restored irqs Building on top of the previous patch, re-enable irqs before checking new pages. alloc_debug_processing() is now called with enabled irqs so we need to remove VM_BUG_ON(!irqs_disabled()); in check_slab() - there doesn't seem to be a need for it anyway. Link: https://lkml.kernel.org/r/20210805152000.12817-18-vbabka@xxxxxxx Signed-off-by: Vlastimil Babka <vbabka@xxxxxxx> Cc: Christoph Lameter <cl@xxxxxxxxx> Cc: David Rientjes <rientjes@xxxxxxxxxx> Cc: Jann Horn <jannh@xxxxxxxxxx> Cc: Jesper Dangaard Brouer <brouer@xxxxxxxxxx> Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx> Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx> Cc: Mike Galbraith <efault@xxxxxx> Cc: Pekka Enberg <penberg@xxxxxxxxxx> Cc: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/slub.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-) --- a/mm/slub.c~mm-slub-check-new-pages-with-restored-irqs +++ a/mm/slub.c @@ -995,8 +995,6 @@ static int check_slab(struct kmem_cache { int maxobj; - VM_BUG_ON(!irqs_disabled()); - if (!PageSlab(page)) { slab_err(s, page, "Not a valid slab page"); return 0; @@ -2788,10 +2786,10 @@ new_objects: lockdep_assert_irqs_disabled(); freelist = get_partial(s, gfpflags, node, &page); + local_irq_restore(flags); if (freelist) goto check_new_page; - local_irq_restore(flags); put_cpu_ptr(s->cpu_slab); page = new_slab(s, gfpflags, node); c = get_cpu_ptr(s->cpu_slab); @@ -2801,7 +2799,6 @@ new_objects: return NULL; } - local_irq_save(flags); /* * No other reference to the page yet so we can * muck around with it freely without cmpxchg @@ -2816,7 +2813,6 @@ check_new_page: if (kmem_cache_debug(s)) { if (!alloc_debug_processing(s, page, freelist, addr)) { /* Slab failed checks. Next slab needed */ - local_irq_restore(flags); goto new_slab; } else { /* @@ -2834,6 +2830,7 @@ check_new_page: */ goto return_single; + local_irq_save(flags); if (unlikely(c->page)) flush_slab(s, c); c->page = page; @@ -2842,6 +2839,7 @@ check_new_page: return_single: + local_irq_save(flags); if (unlikely(c->page)) flush_slab(s, c); c->page = page; _
