diff options
author | Sumanth Korikkar <sumanthk@linux.ibm.com> | 2023-11-20 17:53:52 +0300 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-12-13 20:45:24 +0300 |
commit | e0270ffad4266736ac2d2caa8c9a9ab091292c52 (patch) | |
tree | 7a45b7848c25ffb338be600e19acac7b2f2c9a10 /drivers/base | |
parent | 83dd18e0b76fd346fd4753016ec00377bb636837 (diff) | |
download | linux-e0270ffad4266736ac2d2caa8c9a9ab091292c52.tar.xz |
mm/memory_hotplug: add missing mem_hotplug_lock
commit 001002e73712cdf6b8d9a103648cda3040ad7647 upstream.
From Documentation/core-api/memory-hotplug.rst:
When adding/removing/onlining/offlining memory or adding/removing
heterogeneous/device memory, we should always hold the mem_hotplug_lock
in write mode to serialise memory hotplug (e.g. access to global/zone
variables).
mhp_(de)init_memmap_on_memory() functions can change zone stats and
struct page content, but they are currently called w/o the
mem_hotplug_lock.
When memory block is being offlined and when kmemleak goes through each
populated zone, the following theoretical race conditions could occur:
CPU 0: | CPU 1:
memory_offline() |
-> offline_pages() |
-> mem_hotplug_begin() |
... |
-> mem_hotplug_done() |
| kmemleak_scan()
| -> get_online_mems()
| ...
-> mhp_deinit_memmap_on_memory() |
[not protected by mem_hotplug_begin/done()]|
Marks memory section as offline, | Retrieves zone_start_pfn
poisons vmemmap struct pages and updates | and struct page members.
the zone related data |
| ...
| -> put_online_mems()
Fix this by ensuring mem_hotplug_lock is taken before performing
mhp_init_memmap_on_memory(). Also ensure that
mhp_deinit_memmap_on_memory() holds the lock.
online/offline_pages() are currently only called from
memory_block_online/offline(), so it is safe to move the locking there.
Link: https://lkml.kernel.org/r/20231120145354.308999-2-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: Michal Hocko <mhocko@suse.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: kernel test robot <lkp@intel.com>
Cc: <stable@vger.kernel.org> [5.15+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/base')
-rw-r--r-- | drivers/base/memory.c | 18 |
1 files changed, 15 insertions, 3 deletions
diff --git a/drivers/base/memory.c b/drivers/base/memory.c index f3b9a4d0fa3b..8a13babd826c 100644 --- a/drivers/base/memory.c +++ b/drivers/base/memory.c @@ -180,6 +180,9 @@ static inline unsigned long memblk_nr_poison(struct memory_block *mem) } #endif +/* + * Must acquire mem_hotplug_lock in write mode. + */ static int memory_block_online(struct memory_block *mem) { unsigned long start_pfn = section_nr_to_pfn(mem->start_section_nr); @@ -204,10 +207,11 @@ static int memory_block_online(struct memory_block *mem) if (mem->altmap) nr_vmemmap_pages = mem->altmap->free; + mem_hotplug_begin(); if (nr_vmemmap_pages) { ret = mhp_init_memmap_on_memory(start_pfn, nr_vmemmap_pages, zone); if (ret) - return ret; + goto out; } ret = online_pages(start_pfn + nr_vmemmap_pages, @@ -215,7 +219,7 @@ static int memory_block_online(struct memory_block *mem) if (ret) { if (nr_vmemmap_pages) mhp_deinit_memmap_on_memory(start_pfn, nr_vmemmap_pages); - return ret; + goto out; } /* @@ -227,9 +231,14 @@ static int memory_block_online(struct memory_block *mem) nr_vmemmap_pages); mem->zone = zone; +out: + mem_hotplug_done(); return ret; } +/* + * Must acquire mem_hotplug_lock in write mode. + */ static int memory_block_offline(struct memory_block *mem) { unsigned long start_pfn = section_nr_to_pfn(mem->start_section_nr); @@ -247,6 +256,7 @@ static int memory_block_offline(struct memory_block *mem) if (mem->altmap) nr_vmemmap_pages = mem->altmap->free; + mem_hotplug_begin(); if (nr_vmemmap_pages) adjust_present_page_count(pfn_to_page(start_pfn), mem->group, -nr_vmemmap_pages); @@ -258,13 +268,15 @@ static int memory_block_offline(struct memory_block *mem) if (nr_vmemmap_pages) adjust_present_page_count(pfn_to_page(start_pfn), mem->group, nr_vmemmap_pages); - return ret; + goto out; } if (nr_vmemmap_pages) mhp_deinit_memmap_on_memory(start_pfn, nr_vmemmap_pages); mem->zone = NULL; +out: + mem_hotplug_done(); return ret; } |