FAILED: patch "[PATCH] mm/hugetlb: do not dissolve gigantic pages without runtime" failed to apply to 6.12-stable tree
Subsystems (3)
[email protected]
maintainerThe patch below does not apply to the 6.12-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 <[email protected]>.
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-6.12.y
git checkout FETCH_HEAD
git cherry-pick -x a363c62a653cc8b3e21da9545fa4e028ef50f9c3
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2026092904-charbroil-reroute-765c@gregkh' --subject-prefix 'PATCH 6.12.y' 'HEAD^..'
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From a363c62a653cc8b3e21da9545fa4e028ef50f9c3 Mon Sep 17 00:00:00 2001
From: Longlong Xia <[email protected]>
Date: Sun, 23 Aug 2026 12:40:51 +0800
Subject: [PATCH] mm/hugetlb: do not dissolve gigantic pages without runtime
support
dissolve_free_hugetlb_folio() doesn't check hstate_is_gigantic_no_runtime(h) though remove_hugetlb_folio()/ update_and_free_hugetlb_folio() silently bail for such folios, so it frees a still-listed folio and, on vmemmap restore failure, the add_hugetlb_folio() rollback corrupts the free list.
mm/hugetlb.c +9 -0
@@ -1967,6 +1967,15 @@ int dissolve_free_hugetlb_folio(struct folio *folio)struct hstate *h =folio_hstate (folio);bool adjust_surplus = false; +/* +* remove_hugetlb_folio()/update_and_free_hugetlb_folio() bail +* for gigantic hstates without runtime support, so dissolving one +* here would leave it on the free list and, on vmemmap restore +* failure, the add_hugetlb_folio() rollback corrupts that list. +*/ +if (hstate_is_gigantic_no_runtime (h)) + goto out; +if (!available_huge_pages (h)) goto out;
Sasha Levin
maintainerPATCH 1/2 mm/hugetlb: create hstate_is_gigantic_no_runtime helper
From: Usama Arif <[email protected]>
[ Upstream commit a743e0af503a633e4ca68a100d9b2a1a071fe8ae ]
This is a common condition used to skip operations that cannot be performed on gigantic pages when runtime support is disabled. This helper is introduced as the condition will exist even more when allowing "overcommit" of gigantic hugepages. No functional change intended with this patch.
Stable-dep-of: a363c62a653c ("mm/hugetlb: do not dissolve gigantic pages without runtime support")
--- mm/hugetlb.c | 21 ++++++++++++++++----- 1 file changed, 16 insertions(+), 5 deletions(-)
mm/hugetlb.c +16 -5
@@ -104,6 +104,17 @@ static void hugetlb_free_folio(struct folio *folio)folio_put (folio); } +/* +* Check if the hstate represents gigantic pages but gigantic page +* runtime support is not available. This is a common condition used to +* skip operations that cannot be performed on gigantic pages when runtime +* support is disabled. +*/ +static inline bool hstate_is_gigantic_no_runtime (struct hstate *h) +{ +return hstate_is_gigantic (h) && !gigantic_page_runtime_supported (); +} +static inline bool subpool_is_free (struct hugepage_subpool *spool) {if (spool->count)
@@ -1594,7 +1605,7 @@ static void remove_hugetlb_folio(struct hstate *h, struct folio *folio,VM_BUG_ON_FOLIO (hugetlb_cgroup_from_folio_rsvd (folio), folio);lockdep_assert_held (&hugetlb_lock); -if (hstate_is_gigantic (h) && !gigantic_page_runtime_supported ()) +if (hstate_is_gigantic_no_runtime (h))return ;list_del (&folio->lru);
@@ -1656,7 +1667,7 @@ static void __update_and_free_hugetlb_folio(struct hstate *h, {bool clear_flag =folio_test_hugetlb_vmemmap_optimized (folio); -if (hstate_is_gigantic (h) && !gigantic_page_runtime_supported ()) +if (hstate_is_gigantic_no_runtime (h))return ;/*
@@ -2560,7 +2571,7 @@ static void return_unused_surplus_pages(struct hstate *h,/* Uncommit the reservation */ h->resv_huge_pages -= unused_resv_pages; -if (hstate_is_gigantic (h) && !gigantic_page_runtime_supported ()) +if (hstate_is_gigantic_no_runtime (h)) goto out;/*
@@ -3489,7 +3500,7 @@ static void __init hugetlb_init_hstates(void)* - If CMA allocation is possible, we can not demote * HUGETLB_PAGE_ORDER or smaller size pages. */ -if (hstate_is_gigantic (h) && !gigantic_page_runtime_supported ()) +if (hstate_is_gigantic_no_runtime (h))continue ;if (hugetlb_cma_size && h->order <=HUGETLB_PAGE_ORDER )continue ;
@@ -3934,7 +3945,7 @@ static ssize_t __nr_hugepages_store_common(bool obey_mempolicy,int err;nodemask_t nodes_allowed, *n_mask; -if (hstate_is_gigantic (h) && !gigantic_page_runtime_supported ()) +if (hstate_is_gigantic_no_runtime (h))return -EINVAL ;if (nid ==NUMA_NO_NODE ) {
Signature · 1 line
2.53.0
Sasha Levin
maintainerPATCH 2/2 mm/hugetlb: do not dissolve gigantic pages without runtime support
From: Longlong Xia <[email protected]>
[ Upstream commit a363c62a653cc8b3e21da9545fa4e028ef50f9c3 ]
dissolve_free_hugetlb_folio() doesn't check hstate_is_gigantic_no_runtime(h) though remove_hugetlb_folio()/ update_and_free_hugetlb_folio() silently bail for such folios, so it frees a still-listed folio and, on vmemmap restore failure, the add_hugetlb_folio() rollback corrupts the free list.
--- mm/hugetlb.c | 10 ++++++++++ 1 file changed, 10 insertions(+)
mm/hugetlb.c +10 -0
@@ -2212,6 +2212,16 @@ int dissolve_free_hugetlb_folio(struct folio *folio)if (!folio_ref_count (folio)) {struct hstate *h =folio_hstate (folio); + +/* +* remove_hugetlb_folio()/update_and_free_hugetlb_folio() bail +* for gigantic hstates without runtime support, so dissolving one +* here would leave it on the free list and, on vmemmap restore +* failure, the add_hugetlb_folio() rollback corrupts that list. +*/ +if (hstate_is_gigantic_no_runtime (h)) + goto out; +if (!available_huge_pages (h)) goto out;
Signature · 1 line
2.53.0
Sasha Levin
maintainerPATCH 1/3 mm/hugetlb: fix surplus pages in dissolve_free_huge_page()
In reply to [email protected]From: Jinjiang Tu <[email protected]>
[ Upstream commit cb402bbdabcaa5a765068c5b8673bbfc1c264242 ]
In dissolve_free_huge_page(), free huge pages are dissolved without adjusting surplus count. However, free huge pages may be accounted as surplus pages, and will lead to wrong surplus count.
I reproduce this issue on qemu. The steps are:
1) Node1 is memory-less at first. Hot-add memory to node1 by executing the two commands in qemu monitor:
object_add memory-backend-ram,id=mem1,size=1G
device_add pc-dimm,id=dimm1,memdev=mem1,node=1
2) online one memory block of Node1 with：
echo online_movable > /sys/devices/system/node/node1/memoryX/state
3) create 64 huge pages for node1
4) run a program to reserve (don't consume) all the huge pages
5) echo 0 > nr_huge_pages for node1. After this step, free huge pages in Node1 are surplus.
6) create 80 huge pages for node0
7) offline memory of node1, The memory range to offline contains the free surplus huge pages created in step3) ~ step5)
echo offline > /sys/devices/system/node/node1/memoryX/state
8) kill the program in step 4)
The result:
Node0 Node1
total 80 0 free 80 0 surplus 0 61
To fix it, adjust surplus when destroying huge pages if the node has surplus pages in dissolve_free_hugetlb_folio().
The result with this patch:
Node0 Node1
total 80 0 free 80 0 surplus 0 0
Stable-dep-of: a363c62a653c ("mm/hugetlb: do not dissolve gigantic pages without runtime support")
--- mm/hugetlb.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)
mm/hugetlb.c +6 -2
@@ -2201,6 +2201,8 @@ int dissolve_free_hugetlb_folio(struct folio *folio)if (!folio_ref_count (folio)) {struct hstate *h =folio_hstate (folio); +bool adjust_surplus = false; +if (!available_huge_pages (h)) goto out;
@@ -2223,7 +2225,9 @@ int dissolve_free_hugetlb_folio(struct folio *folio) goto retry; } -remove_hugetlb_folio (h, folio, false); +if (h->surplus_huge_pages_node[folio_nid (folio)]) + adjust_surplus = true; +remove_hugetlb_folio (h, folio, adjust_surplus); h->max_huge_pages--;spin_unlock_irq (&hugetlb_lock);
@@ -2243,7 +2247,7 @@ int dissolve_free_hugetlb_folio(struct folio *folio) rc =hugetlb_vmemmap_restore_folio (h, folio);if (rc) {spin_lock_irq (&hugetlb_lock); -add_hugetlb_folio (h, folio, false); +add_hugetlb_folio (h, folio, adjust_surplus); h->max_huge_pages++; goto out; }
Signature · 1 line
2.53.0
Sasha Levin
maintainerPATCH 2/3 mm/hugetlb: create hstate_is_gigantic_no_runtime helper
From: Usama Arif <[email protected]>
[ Upstream commit a743e0af503a633e4ca68a100d9b2a1a071fe8ae ]
This is a common condition used to skip operations that cannot be performed on gigantic pages when runtime support is disabled. This helper is introduced as the condition will exist even more when allowing "overcommit" of gigantic hugepages. No functional change intended with this patch.
Stable-dep-of: a363c62a653c ("mm/hugetlb: do not dissolve gigantic pages without runtime support")
--- mm/hugetlb.c | 21 ++++++++++++++++----- 1 file changed, 16 insertions(+), 5 deletions(-)
mm/hugetlb.c +16 -5
@@ -104,6 +104,17 @@ static void hugetlb_free_folio(struct folio *folio)folio_put (folio); } +/* +* Check if the hstate represents gigantic pages but gigantic page +* runtime support is not available. This is a common condition used to +* skip operations that cannot be performed on gigantic pages when runtime +* support is disabled. +*/ +static inline bool hstate_is_gigantic_no_runtime (struct hstate *h) +{ +return hstate_is_gigantic (h) && !gigantic_page_runtime_supported (); +} +static inline bool subpool_is_free (struct hugepage_subpool *spool) {if (spool->count)
@@ -1594,7 +1605,7 @@ static void remove_hugetlb_folio(struct hstate *h, struct folio *folio,VM_BUG_ON_FOLIO (hugetlb_cgroup_from_folio_rsvd (folio), folio);lockdep_assert_held (&hugetlb_lock); -if (hstate_is_gigantic (h) && !gigantic_page_runtime_supported ()) +if (hstate_is_gigantic_no_runtime (h))return ;list_del (&folio->lru);
@@ -1656,7 +1667,7 @@ static void __update_and_free_hugetlb_folio(struct hstate *h, {bool clear_flag =folio_test_hugetlb_vmemmap_optimized (folio); -if (hstate_is_gigantic (h) && !gigantic_page_runtime_supported ()) +if (hstate_is_gigantic_no_runtime (h))return ;/*
@@ -2564,7 +2575,7 @@ static void return_unused_surplus_pages(struct hstate *h,/* Uncommit the reservation */ h->resv_huge_pages -= unused_resv_pages; -if (hstate_is_gigantic (h) && !gigantic_page_runtime_supported ()) +if (hstate_is_gigantic_no_runtime (h)) goto out;/*
@@ -3493,7 +3504,7 @@ static void __init hugetlb_init_hstates(void)* - If CMA allocation is possible, we can not demote * HUGETLB_PAGE_ORDER or smaller size pages. */ -if (hstate_is_gigantic (h) && !gigantic_page_runtime_supported ()) +if (hstate_is_gigantic_no_runtime (h))continue ;if (hugetlb_cma_size && h->order <=HUGETLB_PAGE_ORDER )continue ;
@@ -3938,7 +3949,7 @@ static ssize_t __nr_hugepages_store_common(bool obey_mempolicy,int err;nodemask_t nodes_allowed, *n_mask; -if (hstate_is_gigantic (h) && !gigantic_page_runtime_supported ()) +if (hstate_is_gigantic_no_runtime (h))return -EINVAL ;if (nid ==NUMA_NO_NODE ) {
Signature · 1 line
2.53.0
Sasha Levin
maintainerPATCH 3/3 mm/hugetlb: do not dissolve gigantic pages without runtime support
In reply to Sasha LevinFrom: Longlong Xia <[email protected]>
[ Upstream commit a363c62a653cc8b3e21da9545fa4e028ef50f9c3 ]
dissolve_free_hugetlb_folio() doesn't check hstate_is_gigantic_no_runtime(h) though remove_hugetlb_folio()/ update_and_free_hugetlb_folio() silently bail for such folios, so it frees a still-listed folio and, on vmemmap restore failure, the add_hugetlb_folio() rollback corrupts the free list.
--- mm/hugetlb.c | 9 +++++++++ 1 file changed, 9 insertions(+)
mm/hugetlb.c +9 -0
@@ -2214,6 +2214,15 @@ int dissolve_free_hugetlb_folio(struct folio *folio)struct hstate *h =folio_hstate (folio);bool adjust_surplus = false; +/* +* remove_hugetlb_folio()/update_and_free_hugetlb_folio() bail +* for gigantic hstates without runtime support, so dissolving one +* here would leave it on the free list and, on vmemmap restore +* failure, the add_hugetlb_folio() rollback corrupts that list. +*/ +if (hstate_is_gigantic_no_runtime (h)) + goto out; +if (!available_huge_pages (h)) goto out;
Signature · 1 line
2.53.0