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drivers/base/memory: set mem->altmap after successful device registration

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commit a2b8d7827f48ee54a686cb80e4a1d0ff954ec42a upstream.

If __add_memory_block() fails at xa_store() (under memory pressure for
example), device_unregister() is called, which eventually triggers
memory_block_release() with mem->altmap still set, causing a
WARN_ON(mem->altmap).  This was triggered by modifying virtio-mem driver.

Fix this by delaying the assignment of mem->altmap until after
__add_memory_block() has succeeded.

Link: https://lore.kernel.org/20260514092657.3057141-1-georgi.djakov@oss.qualcomm.com
Fixes: 1a8c64e110 ("mm/memory_hotplug: embed vmem_altmap details in memory block")
Signed-off-by: Georgi Djakov <georgi.djakov@oss.qualcomm.com>
Acked-by: Oscar Salvador (SUSE) <osalvador@kernel.org>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Richard Cheng <icheng@nvidia.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: Georgi Djakov <djakov@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Georgi Djakov 2026-05-14 02:26:57 -07:00 • committed by Greg Kroah-Hartman
commit 059ac6252a
1 changed files with 2 additions and 1 deletions
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3
drivers/base/memory.c
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@ -807,7 +807,6 @@ static int add_memory_block(unsigned long block_id, int nid, unsigned long state
mem->start_section_nr = block_id * sections_per_block; mem->start_section_nr = block_id * sections_per_block;
mem->state = state; mem->state = state;
mem->nid = nid; mem->nid = nid;
mem->altmap = altmap;
INIT_LIST_HEAD(&mem->group_next); INIT_LIST_HEAD(&mem->group_next);
#ifndef CONFIG_NUMA #ifndef CONFIG_NUMA
@ -825,6 +824,8 @@ static int add_memory_block(unsigned long block_id, int nid, unsigned long state
if (ret) if (ret)
return ret; return ret;
mem->altmap = altmap;
if (group) { if (group) {
mem->group = group; mem->group = group;
list_add(&mem->group_next, &group->memory_blocks); list_add(&mem->group_next, &group->memory_blocks);