+ drivers-base-memory-add-memory-block-to-memory-group-after-registration-succeeded.patch added to -mm tree

+ drivers-base-memory-add-memory-block-to-memory-group-after-registration-succeeded.patch added to -mm tree

[Andrew Morton]

The patch titled
     Subject: drivers/base/memory: add memory block to memory group after registration succeeded
has been added to the -mm tree.  Its filename is
     drivers-base-memory-add-memory-block-to-memory-group-after-registration-succeeded.patch

This patch should soon appear at
    https://ozlabs.org/~akpm/mmots/broken-out/drivers-base-memory-add-memory-block-to-memory-group-after-registration-succeeded.patch
and later at
    https://ozlabs.org/~akpm/mmotm/broken-out/drivers-base-memory-add-memory-block-to-memory-group-after-registration-succeeded.patch

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------------------------------------------------------
From: David Hildenbrand <david@redhat.com>
Subject: drivers/base/memory: add memory block to memory group after registration succeeded

If register_memory() fails, we freed the memory block but already added
the memory block to the group list, not good.  Let's defer adding the
block to the memory group to after registering the memory block device.

We do handle it properly during unregister_memory(), but that's not
called when the registration fails.

Link: https://lkml.kernel.org/r/20220128144540.153902-1-david@redhat.com
Fixes: 028fc57a1c36 ("drivers/base/memory: introduce "memory groups" to logically group memory blocks")
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: <stable@vger.kernel.org>	[5.15+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 drivers/base/memory.c |    8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

--- a/drivers/base/memory.c~drivers-base-memory-add-memory-block-to-memory-group-after-registration-succeeded
+++ a/drivers/base/memory.c
@@ -663,14 +663,16 @@ static int init_memory_block(unsigned lo
 	mem->nr_vmemmap_pages = nr_vmemmap_pages;
 	INIT_LIST_HEAD(&mem->group_next);
 
+	ret = register_memory(mem);
+	if (ret)
+		return ret;
+
 	if (group) {
 		mem->group = group;
 		list_add(&mem->group_next, &group->memory_blocks);
 	}
 
-	ret = register_memory(mem);
-
-	return ret;
+	return 0;
 }
 
 static int add_memory_block(unsigned long base_section_nr)
_

Patches currently in -mm which might be from david@redhat.com are

mm-optimize-do_wp_page-for-exclusive-pages-in-the-swapcache.patch
mm-optimize-do_wp_page-for-fresh-pages-in-local-lru-pagevecs.patch
mm-slightly-clarify-ksm-logic-in-do_swap_page.patch
mm-streamline-cow-logic-in-do_swap_page.patch
mm-huge_memory-streamline-cow-logic-in-do_huge_pmd_wp_page.patch
mm-khugepaged-remove-reuse_swap_page-usage.patch
mm-swapfile-remove-stale-reuse_swap_page.patch
mm-huge_memory-remove-stale-page_trans_huge_mapcount.patch
mm-huge_memory-remove-stale-locking-logic-from-__split_huge_pmd.patch
drivers-base-memory-add-memory-block-to-memory-group-after-registration-succeeded.patch
proc-vmcore-fix-possible-deadlock-on-concurrent-mmap-and-read.patch