From: Vlastimil Babka <vbabka@suse.cz>

Date: Tue, 11 May 2021 16:56:09 +0200

Subject: mm, slub: check new pages with restored irqs

Git-commit: 9f101ee89465e0b2c11b477f5b55e03039b2c308

Patch-mainline: v5.15-rc1

References: bsc#1189998

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.

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>

---

 mm/slub.c |    8 +++-----

 1 file changed, 3 insertions(+), 5 deletions(-)

--- a/mm/slub.c

+++ b/mm/slub.c

@@ -1009,8 +1009,6 @@ 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;

@@ -2802,10 +2800,10 @@ 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);

@@ -2815,7 +2813,6 @@ 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

@@ -2830,7 +2827,6 @@ 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 {

 			/*

@@ -2848,6 +2844,7 @@ check_new_page:

 		 */

 		goto return_single;

+	local_irq_save(flags);

 	if (unlikely(c->page))

 		flush_slab(s, c);

 	c->page = page;

@@ -2856,6 +2853,7 @@ check_new_page:

 return_single:

+	local_irq_save(flags);

 	if (unlikely(c->page))

 		flush_slab(s, c);

 	c->page = page;