+ mm-memory_hotplug-fix-error-handling-in-add_memory_resource.patch added to mm-hotfixes-unstable branch

+ mm-memory_hotplug-fix-error-handling-in-add_memory_resource.patch added to mm-hotfixes-unstable branch

[Andrew Morton]

The patch titled
     Subject: mm/memory_hotplug: fix error handling in add_memory_resource()
has been added to the -mm mm-hotfixes-unstable branch.  Its filename is
     mm-memory_hotplug-fix-error-handling-in-add_memory_resource.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-memory_hotplug-fix-error-handling-in-add_memory_resource.patch

This patch will later appear in the mm-hotfixes-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: Sumanth Korikkar <sumanthk@linux.ibm.com>
Subject: mm/memory_hotplug: fix error handling in add_memory_resource()
Date: Mon, 20 Nov 2023 15:53:53 +0100

In add_memory_resource(), creation of memory block devices occurs after
successful call to arch_add_memory().  However, creation of memory block
devices could fail.  In that case, arch_remove_memory() is called to
perform necessary cleanup.

Currently with or without altmap support, arch_remove_memory() is always
passed with altmap set to NULL during error handling.  This leads to
freeing of struct pages using free_pages(), eventhough the allocation
might have been performed with altmap support via
altmap_alloc_block_buf().

Fix the error handling by passing altmap in arch_remove_memory(). This
ensures the following:
* When altmap is disabled, deallocation of the struct pages array occurs
  via free_pages().
* When altmap is enabled, deallocation occurs via vmem_altmap_free().

Link: https://lkml.kernel.org/r/20231120145354.308999-3-sumanthk@linux.ibm.com
Fixes: a08a2ae34613 ("mm,memory_hotplug: allocate memmap from the added memory range")
Signed-off-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
Reviewed-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: kernel test robot <lkp@intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: <stable@vger.kernel.org>	[5.15+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/memory_hotplug.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/mm/memory_hotplug.c~mm-memory_hotplug-fix-error-handling-in-add_memory_resource
+++ a/mm/memory_hotplug.c
@@ -1458,7 +1458,7 @@ int __ref add_memory_resource(int nid, s
 	/* create memory block devices after memory was added */
 	ret = create_memory_block_devices(start, size, params.altmap, group);
 	if (ret) {
-		arch_remove_memory(start, size, NULL);
+		arch_remove_memory(start, size, params.altmap);
 		goto error_free;
 	}
 
_

Patches currently in -mm which might be from sumanthk@linux.ibm.com are

mm-memory_hotplug-add-missing-mem_hotplug_lock.patch
mm-memory_hotplug-fix-error-handling-in-add_memory_resource.patch
mm-use-vmem_altmap-code-without-config_zone_device.patch