The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y git checkout FETCH_HEAD git cherry-pick -x 001002e73712cdf6b8d9a103648cda3040ad7647 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2023120927-immobile-half-41d8@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..
Possible dependencies:
001002e73712 ("mm/memory_hotplug: add missing mem_hotplug_lock") 1a8c64e11043 ("mm/memory_hotplug: embed vmem_altmap details in memory block") 2d1f649c7c08 ("mm/memory_hotplug: support memmap_on_memory when memmap is not aligned to pageblocks") 85a2b4b08f20 ("mm/memory_hotplug: allow architecture to override memmap on memory support check") e3c2bfdd33a3 ("mm/memory_hotplug: allow memmap on memory hotplug request to fallback") 5033091de814 ("mm/hwpoison: introduce per-memory_block hwpoison counter") a46c9304b4bb ("mm/hwpoison: pass pfn to num_poisoned_pages_*()") d027122d8363 ("mm/hwpoison: move definitions of num_poisoned_pages_* to memory-failure.c") e591ef7d96d6 ("mm,hwpoison,hugetlb,memory_hotplug: hotremove memory section with hwpoisoned hugepage") 0d206b5d2e0d ("mm/swap: add swp_offset_pfn() to fetch PFN from swap entry") eba4d770efc8 ("mm/swap: comment all the ifdef in swapops.h") 21c9e90ab9a4 ("mm, hwpoison: use num_poisoned_pages_sub() to decrease num_poisoned_pages") f36a5543a748 ("mm, hwpoison: fix page refcnt leaking in try_memory_failure_hugetlb()") 7453bf621cfa ("mm, hwpoison: make __page_handle_poison returns int") 38f6d29397cc ("mm, hwpoison: set PG_hwpoison for busy hugetlb pages") ac5fcde0a96a ("mm, hwpoison: make unpoison aware of raw error info in hwpoisoned hugepage") 161df60e9e89 ("mm, hwpoison, hugetlb: support saving mechanism of raw error pages") 6213834c10de ("mm: hugetlb_vmemmap: improve hugetlb_vmemmap code readability") 998a2997885f ("mm: hugetlb_vmemmap: move vmemmap code related to HugeTLB to hugetlb_vmemmap.c") dff033818a06 ("mm: hugetlb_vmemmap: introduce the name HVO")
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 001002e73712cdf6b8d9a103648cda3040ad7647 Mon Sep 17 00:00:00 2001 From: Sumanth Korikkar sumanthk@linux.ibm.com Date: Mon, 20 Nov 2023 15:53:52 +0100 Subject: [PATCH] mm/memory_hotplug: add missing mem_hotplug_lock
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
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; }
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index ab41a511e20a..bb908289679e 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -1129,6 +1129,9 @@ void mhp_deinit_memmap_on_memory(unsigned long pfn, unsigned long nr_pages) kasan_remove_zero_shadow(__va(PFN_PHYS(pfn)), PFN_PHYS(nr_pages)); }
+/* + * Must be called with mem_hotplug_lock in write mode. + */ int __ref online_pages(unsigned long pfn, unsigned long nr_pages, struct zone *zone, struct memory_group *group) { @@ -1149,7 +1152,6 @@ int __ref online_pages(unsigned long pfn, unsigned long nr_pages, !IS_ALIGNED(pfn + nr_pages, PAGES_PER_SECTION))) return -EINVAL;
- mem_hotplug_begin();
/* associate pfn range with the zone */ move_pfn_range_to_zone(zone, pfn, nr_pages, NULL, MIGRATE_ISOLATE); @@ -1208,7 +1210,6 @@ int __ref online_pages(unsigned long pfn, unsigned long nr_pages, writeback_set_ratelimit();
memory_notify(MEM_ONLINE, &arg); - mem_hotplug_done(); return 0;
failed_addition: @@ -1217,7 +1218,6 @@ int __ref online_pages(unsigned long pfn, unsigned long nr_pages, (((unsigned long long) pfn + nr_pages) << PAGE_SHIFT) - 1); memory_notify(MEM_CANCEL_ONLINE, &arg); remove_pfn_range_from_zone(zone, pfn, nr_pages); - mem_hotplug_done(); return ret; }
@@ -1863,6 +1863,9 @@ static int count_system_ram_pages_cb(unsigned long start_pfn, return 0; }
+/* + * Must be called with mem_hotplug_lock in write mode. + */ int __ref offline_pages(unsigned long start_pfn, unsigned long nr_pages, struct zone *zone, struct memory_group *group) { @@ -1885,8 +1888,6 @@ int __ref offline_pages(unsigned long start_pfn, unsigned long nr_pages, !IS_ALIGNED(start_pfn + nr_pages, PAGES_PER_SECTION))) return -EINVAL;
- mem_hotplug_begin(); - /* * Don't allow to offline memory blocks that contain holes. * Consequently, memory blocks with holes can never get onlined @@ -2031,7 +2032,6 @@ int __ref offline_pages(unsigned long start_pfn, unsigned long nr_pages,
memory_notify(MEM_OFFLINE, &arg); remove_pfn_range_from_zone(zone, start_pfn, nr_pages); - mem_hotplug_done(); return 0;
failed_removal_isolated: @@ -2046,7 +2046,6 @@ int __ref offline_pages(unsigned long start_pfn, unsigned long nr_pages, (unsigned long long) start_pfn << PAGE_SHIFT, ((unsigned long long) end_pfn << PAGE_SHIFT) - 1, reason); - mem_hotplug_done(); return ret; }