From: Vlastimil Babka <vbabka@suse.cz>
Date: Mon, 23 Aug 2021 23:58:58 +0000 (+1000)
Subject: mm, slub: check new pages with restored irqs
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=1567f70ea4187aa68b3ba3f9ff0b3dac47b01eb6;p=users%2Fjedix%2Flinux-maple.git

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@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Jann Horn <jannh@google.com>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
---

diff --git a/mm/slub.c b/mm/slub.c
index fddfb0629b8e..d5ac278084cf 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -995,8 +995,6 @@ static int check_slab(struct kmem_cache *s, struct page *page)
 {
 	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;