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* FAILED: patch "[PATCH] mm/vmalloc, mm/kasan: respect gfp mask in" failed to apply to 6.12-stable tree
@ 2025-09-13 12:25 gregkh
  2025-09-13 18:59 ` [PATCH 6.12.y 1/2] kasan: avoid sleepable page allocation from atomic context Sasha Levin
  0 siblings, 1 reply; 3+ messages in thread
From: gregkh @ 2025-09-13 12:25 UTC (permalink / raw)
  To: urezki, akpm, andreyknvl, bhe, dvyukov, glider, mhocko,
	ryabinin.a.a, stable, vincenzo.frascino
  Cc: stable


The 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 <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-6.12.y
git checkout FETCH_HEAD
git cherry-pick -x 79357cd06d41d0f5a11b17d7c86176e395d10ef2
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2025091303-hush-compactor-2f22@gregkh' --subject-prefix 'PATCH 6.12.y' HEAD^..

Possible dependencies:



thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 79357cd06d41d0f5a11b17d7c86176e395d10ef2 Mon Sep 17 00:00:00 2001
From: "Uladzislau Rezki (Sony)" <urezki@gmail.com>
Date: Sun, 31 Aug 2025 14:10:58 +0200
Subject: [PATCH] mm/vmalloc, mm/kasan: respect gfp mask in
 kasan_populate_vmalloc()

kasan_populate_vmalloc() and its helpers ignore the caller's gfp_mask and
always allocate memory using the hardcoded GFP_KERNEL flag.  This makes
them inconsistent with vmalloc(), which was recently extended to support
GFP_NOFS and GFP_NOIO allocations.

Page table allocations performed during shadow population also ignore the
external gfp_mask.  To preserve the intended semantics of GFP_NOFS and
GFP_NOIO, wrap the apply_to_page_range() calls into the appropriate
memalloc scope.

xfs calls vmalloc with GFP_NOFS, so this bug could lead to deadlock.

There was a report here
https://lkml.kernel.org/r/686ea951.050a0220.385921.0016.GAE@google.com

This patch:
 - Extends kasan_populate_vmalloc() and helpers to take gfp_mask;
 - Passes gfp_mask down to alloc_pages_bulk() and __get_free_page();
 - Enforces GFP_NOFS/NOIO semantics with memalloc_*_save()/restore()
   around apply_to_page_range();
 - Updates vmalloc.c and percpu allocator call sites accordingly.

Link: https://lkml.kernel.org/r/20250831121058.92971-1-urezki@gmail.com
Fixes: 451769ebb7e7 ("mm/vmalloc: alloc GFP_NO{FS,IO} for vmalloc")
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Reported-by: syzbot+3470c9ffee63e4abafeb@syzkaller.appspotmail.com
Reviewed-by: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/include/linux/kasan.h b/include/linux/kasan.h
index 890011071f2b..fe5ce9215821 100644
--- a/include/linux/kasan.h
+++ b/include/linux/kasan.h
@@ -562,7 +562,7 @@ static inline void kasan_init_hw_tags(void) { }
 #if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)
 
 void kasan_populate_early_vm_area_shadow(void *start, unsigned long size);
-int kasan_populate_vmalloc(unsigned long addr, unsigned long size);
+int kasan_populate_vmalloc(unsigned long addr, unsigned long size, gfp_t gfp_mask);
 void kasan_release_vmalloc(unsigned long start, unsigned long end,
 			   unsigned long free_region_start,
 			   unsigned long free_region_end,
@@ -574,7 +574,7 @@ static inline void kasan_populate_early_vm_area_shadow(void *start,
 						       unsigned long size)
 { }
 static inline int kasan_populate_vmalloc(unsigned long start,
-					unsigned long size)
+					unsigned long size, gfp_t gfp_mask)
 {
 	return 0;
 }
@@ -610,7 +610,7 @@ static __always_inline void kasan_poison_vmalloc(const void *start,
 static inline void kasan_populate_early_vm_area_shadow(void *start,
 						       unsigned long size) { }
 static inline int kasan_populate_vmalloc(unsigned long start,
-					unsigned long size)
+					unsigned long size, gfp_t gfp_mask)
 {
 	return 0;
 }
diff --git a/mm/kasan/shadow.c b/mm/kasan/shadow.c
index e2ceebf737ef..11d472a5c4e8 100644
--- a/mm/kasan/shadow.c
+++ b/mm/kasan/shadow.c
@@ -336,13 +336,13 @@ static void ___free_pages_bulk(struct page **pages, int nr_pages)
 	}
 }
 
-static int ___alloc_pages_bulk(struct page **pages, int nr_pages)
+static int ___alloc_pages_bulk(struct page **pages, int nr_pages, gfp_t gfp_mask)
 {
 	unsigned long nr_populated, nr_total = nr_pages;
 	struct page **page_array = pages;
 
 	while (nr_pages) {
-		nr_populated = alloc_pages_bulk(GFP_KERNEL, nr_pages, pages);
+		nr_populated = alloc_pages_bulk(gfp_mask, nr_pages, pages);
 		if (!nr_populated) {
 			___free_pages_bulk(page_array, nr_total - nr_pages);
 			return -ENOMEM;
@@ -354,25 +354,42 @@ static int ___alloc_pages_bulk(struct page **pages, int nr_pages)
 	return 0;
 }
 
-static int __kasan_populate_vmalloc(unsigned long start, unsigned long end)
+static int __kasan_populate_vmalloc(unsigned long start, unsigned long end, gfp_t gfp_mask)
 {
 	unsigned long nr_pages, nr_total = PFN_UP(end - start);
 	struct vmalloc_populate_data data;
+	unsigned int flags;
 	int ret = 0;
 
-	data.pages = (struct page **)__get_free_page(GFP_KERNEL | __GFP_ZERO);
+	data.pages = (struct page **)__get_free_page(gfp_mask | __GFP_ZERO);
 	if (!data.pages)
 		return -ENOMEM;
 
 	while (nr_total) {
 		nr_pages = min(nr_total, PAGE_SIZE / sizeof(data.pages[0]));
-		ret = ___alloc_pages_bulk(data.pages, nr_pages);
+		ret = ___alloc_pages_bulk(data.pages, nr_pages, gfp_mask);
 		if (ret)
 			break;
 
 		data.start = start;
+
+		/*
+		 * page tables allocations ignore external gfp mask, enforce it
+		 * by the scope API
+		 */
+		if ((gfp_mask & (__GFP_FS | __GFP_IO)) == __GFP_IO)
+			flags = memalloc_nofs_save();
+		else if ((gfp_mask & (__GFP_FS | __GFP_IO)) == 0)
+			flags = memalloc_noio_save();
+
 		ret = apply_to_page_range(&init_mm, start, nr_pages * PAGE_SIZE,
 					  kasan_populate_vmalloc_pte, &data);
+
+		if ((gfp_mask & (__GFP_FS | __GFP_IO)) == __GFP_IO)
+			memalloc_nofs_restore(flags);
+		else if ((gfp_mask & (__GFP_FS | __GFP_IO)) == 0)
+			memalloc_noio_restore(flags);
+
 		___free_pages_bulk(data.pages, nr_pages);
 		if (ret)
 			break;
@@ -386,7 +403,7 @@ static int __kasan_populate_vmalloc(unsigned long start, unsigned long end)
 	return ret;
 }
 
-int kasan_populate_vmalloc(unsigned long addr, unsigned long size)
+int kasan_populate_vmalloc(unsigned long addr, unsigned long size, gfp_t gfp_mask)
 {
 	unsigned long shadow_start, shadow_end;
 	int ret;
@@ -415,7 +432,7 @@ int kasan_populate_vmalloc(unsigned long addr, unsigned long size)
 	shadow_start = PAGE_ALIGN_DOWN(shadow_start);
 	shadow_end = PAGE_ALIGN(shadow_end);
 
-	ret = __kasan_populate_vmalloc(shadow_start, shadow_end);
+	ret = __kasan_populate_vmalloc(shadow_start, shadow_end, gfp_mask);
 	if (ret)
 		return ret;
 
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 6dbcdceecae1..5edd536ba9d2 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -2026,6 +2026,8 @@ static struct vmap_area *alloc_vmap_area(unsigned long size,
 	if (unlikely(!vmap_initialized))
 		return ERR_PTR(-EBUSY);
 
+	/* Only reclaim behaviour flags are relevant. */
+	gfp_mask = gfp_mask & GFP_RECLAIM_MASK;
 	might_sleep();
 
 	/*
@@ -2038,8 +2040,6 @@ static struct vmap_area *alloc_vmap_area(unsigned long size,
 	 */
 	va = node_alloc(size, align, vstart, vend, &addr, &vn_id);
 	if (!va) {
-		gfp_mask = gfp_mask & GFP_RECLAIM_MASK;
-
 		va = kmem_cache_alloc_node(vmap_area_cachep, gfp_mask, node);
 		if (unlikely(!va))
 			return ERR_PTR(-ENOMEM);
@@ -2089,7 +2089,7 @@ static struct vmap_area *alloc_vmap_area(unsigned long size,
 	BUG_ON(va->va_start < vstart);
 	BUG_ON(va->va_end > vend);
 
-	ret = kasan_populate_vmalloc(addr, size);
+	ret = kasan_populate_vmalloc(addr, size, gfp_mask);
 	if (ret) {
 		free_vmap_area(va);
 		return ERR_PTR(ret);
@@ -4826,7 +4826,7 @@ struct vm_struct **pcpu_get_vm_areas(const unsigned long *offsets,
 
 	/* populate the kasan shadow space */
 	for (area = 0; area < nr_vms; area++) {
-		if (kasan_populate_vmalloc(vas[area]->va_start, sizes[area]))
+		if (kasan_populate_vmalloc(vas[area]->va_start, sizes[area], GFP_KERNEL))
 			goto err_free_shadow;
 	}
 


^ permalink raw reply related	[flat|nested] 3+ messages in thread

* [PATCH 6.12.y 1/2] kasan: avoid sleepable page allocation from atomic context
  2025-09-13 12:25 FAILED: patch "[PATCH] mm/vmalloc, mm/kasan: respect gfp mask in" failed to apply to 6.12-stable tree gregkh
@ 2025-09-13 18:59 ` Sasha Levin
  2025-09-13 18:59   ` [PATCH 6.12.y 2/2] mm/vmalloc, mm/kasan: respect gfp mask in kasan_populate_vmalloc() Sasha Levin
  0 siblings, 1 reply; 3+ messages in thread
From: Sasha Levin @ 2025-09-13 18:59 UTC (permalink / raw)
  To: stable
  Cc: Alexander Gordeev, Andrey Ryabinin, Harry Yoo, Daniel Axtens,
	Andrew Morton, Sasha Levin

From: Alexander Gordeev <agordeev@linux.ibm.com>

[ Upstream commit b6ea95a34cbd014ab6ade4248107b86b0aaf2d6c ]

apply_to_pte_range() enters the lazy MMU mode and then invokes
kasan_populate_vmalloc_pte() callback on each page table walk iteration.
However, the callback can go into sleep when trying to allocate a single
page, e.g.  if an architecutre disables preemption on lazy MMU mode enter.

On s390 if make arch_enter_lazy_mmu_mode() -> preempt_enable() and
arch_leave_lazy_mmu_mode() -> preempt_disable(), such crash occurs:

[    0.663336] BUG: sleeping function called from invalid context at ./include/linux/sched/mm.h:321
[    0.663348] in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 2, name: kthreadd
[    0.663358] preempt_count: 1, expected: 0
[    0.663366] RCU nest depth: 0, expected: 0
[    0.663375] no locks held by kthreadd/2.
[    0.663383] Preemption disabled at:
[    0.663386] [<0002f3284cbb4eda>] apply_to_pte_range+0xfa/0x4a0
[    0.663405] CPU: 0 UID: 0 PID: 2 Comm: kthreadd Not tainted 6.15.0-rc5-gcc-kasan-00043-gd76bb1ebb558-dirty #162 PREEMPT
[    0.663408] Hardware name: IBM 3931 A01 701 (KVM/Linux)
[    0.663409] Call Trace:
[    0.663410]  [<0002f3284c385f58>] dump_stack_lvl+0xe8/0x140
[    0.663413]  [<0002f3284c507b9e>] __might_resched+0x66e/0x700
[    0.663415]  [<0002f3284cc4f6c0>] __alloc_frozen_pages_noprof+0x370/0x4b0
[    0.663419]  [<0002f3284ccc73c0>] alloc_pages_mpol+0x1a0/0x4a0
[    0.663421]  [<0002f3284ccc8518>] alloc_frozen_pages_noprof+0x88/0xc0
[    0.663424]  [<0002f3284ccc8572>] alloc_pages_noprof+0x22/0x120
[    0.663427]  [<0002f3284cc341ac>] get_free_pages_noprof+0x2c/0xc0
[    0.663429]  [<0002f3284cceba70>] kasan_populate_vmalloc_pte+0x50/0x120
[    0.663433]  [<0002f3284cbb4ef8>] apply_to_pte_range+0x118/0x4a0
[    0.663435]  [<0002f3284cbc7c14>] apply_to_pmd_range+0x194/0x3e0
[    0.663437]  [<0002f3284cbc99be>] __apply_to_page_range+0x2fe/0x7a0
[    0.663440]  [<0002f3284cbc9e88>] apply_to_page_range+0x28/0x40
[    0.663442]  [<0002f3284ccebf12>] kasan_populate_vmalloc+0x82/0xa0
[    0.663445]  [<0002f3284cc1578c>] alloc_vmap_area+0x34c/0xc10
[    0.663448]  [<0002f3284cc1c2a6>] __get_vm_area_node+0x186/0x2a0
[    0.663451]  [<0002f3284cc1e696>] __vmalloc_node_range_noprof+0x116/0x310
[    0.663454]  [<0002f3284cc1d950>] __vmalloc_node_noprof+0xd0/0x110
[    0.663457]  [<0002f3284c454b88>] alloc_thread_stack_node+0xf8/0x330
[    0.663460]  [<0002f3284c458d56>] dup_task_struct+0x66/0x4d0
[    0.663463]  [<0002f3284c45be90>] copy_process+0x280/0x4b90
[    0.663465]  [<0002f3284c460940>] kernel_clone+0xd0/0x4b0
[    0.663467]  [<0002f3284c46115e>] kernel_thread+0xbe/0xe0
[    0.663469]  [<0002f3284c4e440e>] kthreadd+0x50e/0x7f0
[    0.663472]  [<0002f3284c38c04a>] __ret_from_fork+0x8a/0xf0
[    0.663475]  [<0002f3284ed57ff2>] ret_from_fork+0xa/0x38

Instead of allocating single pages per-PTE, bulk-allocate the shadow
memory prior to applying kasan_populate_vmalloc_pte() callback on a page
range.

Link: https://lkml.kernel.org/r/c61d3560297c93ed044f0b1af085610353a06a58.1747316918.git.agordeev@linux.ibm.com
Fixes: 3c5c3cfb9ef4 ("kasan: support backing vmalloc space with real shadow memory")
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Suggested-by: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Reviewed-by: Harry Yoo <harry.yoo@oracle.com>
Cc: Daniel Axtens <dja@axtens.net>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Stable-dep-of: 79357cd06d41 ("mm/vmalloc, mm/kasan: respect gfp mask in kasan_populate_vmalloc()")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 mm/kasan/shadow.c | 92 +++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 78 insertions(+), 14 deletions(-)

diff --git a/mm/kasan/shadow.c b/mm/kasan/shadow.c
index 88d1c9dcb5072..d2c70cd2afb1d 100644
--- a/mm/kasan/shadow.c
+++ b/mm/kasan/shadow.c
@@ -292,33 +292,99 @@ void __init __weak kasan_populate_early_vm_area_shadow(void *start,
 {
 }
 
+struct vmalloc_populate_data {
+	unsigned long start;
+	struct page **pages;
+};
+
 static int kasan_populate_vmalloc_pte(pte_t *ptep, unsigned long addr,
-				      void *unused)
+				      void *_data)
 {
-	unsigned long page;
+	struct vmalloc_populate_data *data = _data;
+	struct page *page;
 	pte_t pte;
+	int index;
 
 	if (likely(!pte_none(ptep_get(ptep))))
 		return 0;
 
-	page = __get_free_page(GFP_KERNEL);
-	if (!page)
-		return -ENOMEM;
-
-	__memset((void *)page, KASAN_VMALLOC_INVALID, PAGE_SIZE);
-	pte = pfn_pte(PFN_DOWN(__pa(page)), PAGE_KERNEL);
+	index = PFN_DOWN(addr - data->start);
+	page = data->pages[index];
+	__memset(page_to_virt(page), KASAN_VMALLOC_INVALID, PAGE_SIZE);
+	pte = pfn_pte(page_to_pfn(page), PAGE_KERNEL);
 
 	spin_lock(&init_mm.page_table_lock);
 	if (likely(pte_none(ptep_get(ptep)))) {
 		set_pte_at(&init_mm, addr, ptep, pte);
-		page = 0;
+		data->pages[index] = NULL;
 	}
 	spin_unlock(&init_mm.page_table_lock);
-	if (page)
-		free_page(page);
+
+	return 0;
+}
+
+static void ___free_pages_bulk(struct page **pages, int nr_pages)
+{
+	int i;
+
+	for (i = 0; i < nr_pages; i++) {
+		if (pages[i]) {
+			__free_pages(pages[i], 0);
+			pages[i] = NULL;
+		}
+	}
+}
+
+static int ___alloc_pages_bulk(struct page **pages, int nr_pages)
+{
+	unsigned long nr_populated, nr_total = nr_pages;
+	struct page **page_array = pages;
+
+	while (nr_pages) {
+		nr_populated = alloc_pages_bulk(GFP_KERNEL, nr_pages, pages);
+		if (!nr_populated) {
+			___free_pages_bulk(page_array, nr_total - nr_pages);
+			return -ENOMEM;
+		}
+		pages += nr_populated;
+		nr_pages -= nr_populated;
+	}
+
 	return 0;
 }
 
+static int __kasan_populate_vmalloc(unsigned long start, unsigned long end)
+{
+	unsigned long nr_pages, nr_total = PFN_UP(end - start);
+	struct vmalloc_populate_data data;
+	int ret = 0;
+
+	data.pages = (struct page **)__get_free_page(GFP_KERNEL | __GFP_ZERO);
+	if (!data.pages)
+		return -ENOMEM;
+
+	while (nr_total) {
+		nr_pages = min(nr_total, PAGE_SIZE / sizeof(data.pages[0]));
+		ret = ___alloc_pages_bulk(data.pages, nr_pages);
+		if (ret)
+			break;
+
+		data.start = start;
+		ret = apply_to_page_range(&init_mm, start, nr_pages * PAGE_SIZE,
+					  kasan_populate_vmalloc_pte, &data);
+		___free_pages_bulk(data.pages, nr_pages);
+		if (ret)
+			break;
+
+		start += nr_pages * PAGE_SIZE;
+		nr_total -= nr_pages;
+	}
+
+	free_page((unsigned long)data.pages);
+
+	return ret;
+}
+
 int kasan_populate_vmalloc(unsigned long addr, unsigned long size)
 {
 	unsigned long shadow_start, shadow_end;
@@ -348,9 +414,7 @@ int kasan_populate_vmalloc(unsigned long addr, unsigned long size)
 	shadow_start = PAGE_ALIGN_DOWN(shadow_start);
 	shadow_end = PAGE_ALIGN(shadow_end);
 
-	ret = apply_to_page_range(&init_mm, shadow_start,
-				  shadow_end - shadow_start,
-				  kasan_populate_vmalloc_pte, NULL);
+	ret = __kasan_populate_vmalloc(shadow_start, shadow_end);
 	if (ret)
 		return ret;
 
-- 
2.51.0


^ permalink raw reply related	[flat|nested] 3+ messages in thread

* [PATCH 6.12.y 2/2] mm/vmalloc, mm/kasan: respect gfp mask in kasan_populate_vmalloc()
  2025-09-13 18:59 ` [PATCH 6.12.y 1/2] kasan: avoid sleepable page allocation from atomic context Sasha Levin
@ 2025-09-13 18:59   ` Sasha Levin
  0 siblings, 0 replies; 3+ messages in thread
From: Sasha Levin @ 2025-09-13 18:59 UTC (permalink / raw)
  To: stable
  Cc: Uladzislau Rezki (Sony), syzbot+3470c9ffee63e4abafeb,
	Andrey Ryabinin, Baoquan He, Michal Hocko, Alexander Potapenko,
	Andrey Konovalov, Dmitry Vyukov, Vincenzo Frascino, Andrew Morton,
	Sasha Levin

From: "Uladzislau Rezki (Sony)" <urezki@gmail.com>

[ Upstream commit 79357cd06d41d0f5a11b17d7c86176e395d10ef2 ]

kasan_populate_vmalloc() and its helpers ignore the caller's gfp_mask and
always allocate memory using the hardcoded GFP_KERNEL flag.  This makes
them inconsistent with vmalloc(), which was recently extended to support
GFP_NOFS and GFP_NOIO allocations.

Page table allocations performed during shadow population also ignore the
external gfp_mask.  To preserve the intended semantics of GFP_NOFS and
GFP_NOIO, wrap the apply_to_page_range() calls into the appropriate
memalloc scope.

xfs calls vmalloc with GFP_NOFS, so this bug could lead to deadlock.

There was a report here
https://lkml.kernel.org/r/686ea951.050a0220.385921.0016.GAE@google.com

This patch:
 - Extends kasan_populate_vmalloc() and helpers to take gfp_mask;
 - Passes gfp_mask down to alloc_pages_bulk() and __get_free_page();
 - Enforces GFP_NOFS/NOIO semantics with memalloc_*_save()/restore()
   around apply_to_page_range();
 - Updates vmalloc.c and percpu allocator call sites accordingly.

Link: https://lkml.kernel.org/r/20250831121058.92971-1-urezki@gmail.com
Fixes: 451769ebb7e7 ("mm/vmalloc: alloc GFP_NO{FS,IO} for vmalloc")
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Reported-by: syzbot+3470c9ffee63e4abafeb@syzkaller.appspotmail.com
Reviewed-by: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 include/linux/kasan.h |  6 +++---
 mm/kasan/shadow.c     | 31 ++++++++++++++++++++++++-------
 mm/vmalloc.c          |  8 ++++----
 3 files changed, 31 insertions(+), 14 deletions(-)

diff --git a/include/linux/kasan.h b/include/linux/kasan.h
index 6bbfc8aa42e8f..ef81c543ea2a0 100644
--- a/include/linux/kasan.h
+++ b/include/linux/kasan.h
@@ -564,7 +564,7 @@ static inline void kasan_init_hw_tags(void) { }
 #if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)
 
 void kasan_populate_early_vm_area_shadow(void *start, unsigned long size);
-int kasan_populate_vmalloc(unsigned long addr, unsigned long size);
+int kasan_populate_vmalloc(unsigned long addr, unsigned long size, gfp_t gfp_mask);
 void kasan_release_vmalloc(unsigned long start, unsigned long end,
 			   unsigned long free_region_start,
 			   unsigned long free_region_end,
@@ -576,7 +576,7 @@ static inline void kasan_populate_early_vm_area_shadow(void *start,
 						       unsigned long size)
 { }
 static inline int kasan_populate_vmalloc(unsigned long start,
-					unsigned long size)
+					unsigned long size, gfp_t gfp_mask)
 {
 	return 0;
 }
@@ -612,7 +612,7 @@ static __always_inline void kasan_poison_vmalloc(const void *start,
 static inline void kasan_populate_early_vm_area_shadow(void *start,
 						       unsigned long size) { }
 static inline int kasan_populate_vmalloc(unsigned long start,
-					unsigned long size)
+					unsigned long size, gfp_t gfp_mask)
 {
 	return 0;
 }
diff --git a/mm/kasan/shadow.c b/mm/kasan/shadow.c
index d2c70cd2afb1d..c7c0be1191737 100644
--- a/mm/kasan/shadow.c
+++ b/mm/kasan/shadow.c
@@ -335,13 +335,13 @@ static void ___free_pages_bulk(struct page **pages, int nr_pages)
 	}
 }
 
-static int ___alloc_pages_bulk(struct page **pages, int nr_pages)
+static int ___alloc_pages_bulk(struct page **pages, int nr_pages, gfp_t gfp_mask)
 {
 	unsigned long nr_populated, nr_total = nr_pages;
 	struct page **page_array = pages;
 
 	while (nr_pages) {
-		nr_populated = alloc_pages_bulk(GFP_KERNEL, nr_pages, pages);
+		nr_populated = alloc_pages_bulk(gfp_mask, nr_pages, pages);
 		if (!nr_populated) {
 			___free_pages_bulk(page_array, nr_total - nr_pages);
 			return -ENOMEM;
@@ -353,25 +353,42 @@ static int ___alloc_pages_bulk(struct page **pages, int nr_pages)
 	return 0;
 }
 
-static int __kasan_populate_vmalloc(unsigned long start, unsigned long end)
+static int __kasan_populate_vmalloc(unsigned long start, unsigned long end, gfp_t gfp_mask)
 {
 	unsigned long nr_pages, nr_total = PFN_UP(end - start);
 	struct vmalloc_populate_data data;
+	unsigned int flags;
 	int ret = 0;
 
-	data.pages = (struct page **)__get_free_page(GFP_KERNEL | __GFP_ZERO);
+	data.pages = (struct page **)__get_free_page(gfp_mask | __GFP_ZERO);
 	if (!data.pages)
 		return -ENOMEM;
 
 	while (nr_total) {
 		nr_pages = min(nr_total, PAGE_SIZE / sizeof(data.pages[0]));
-		ret = ___alloc_pages_bulk(data.pages, nr_pages);
+		ret = ___alloc_pages_bulk(data.pages, nr_pages, gfp_mask);
 		if (ret)
 			break;
 
 		data.start = start;
+
+		/*
+		 * page tables allocations ignore external gfp mask, enforce it
+		 * by the scope API
+		 */
+		if ((gfp_mask & (__GFP_FS | __GFP_IO)) == __GFP_IO)
+			flags = memalloc_nofs_save();
+		else if ((gfp_mask & (__GFP_FS | __GFP_IO)) == 0)
+			flags = memalloc_noio_save();
+
 		ret = apply_to_page_range(&init_mm, start, nr_pages * PAGE_SIZE,
 					  kasan_populate_vmalloc_pte, &data);
+
+		if ((gfp_mask & (__GFP_FS | __GFP_IO)) == __GFP_IO)
+			memalloc_nofs_restore(flags);
+		else if ((gfp_mask & (__GFP_FS | __GFP_IO)) == 0)
+			memalloc_noio_restore(flags);
+
 		___free_pages_bulk(data.pages, nr_pages);
 		if (ret)
 			break;
@@ -385,7 +402,7 @@ static int __kasan_populate_vmalloc(unsigned long start, unsigned long end)
 	return ret;
 }
 
-int kasan_populate_vmalloc(unsigned long addr, unsigned long size)
+int kasan_populate_vmalloc(unsigned long addr, unsigned long size, gfp_t gfp_mask)
 {
 	unsigned long shadow_start, shadow_end;
 	int ret;
@@ -414,7 +431,7 @@ int kasan_populate_vmalloc(unsigned long addr, unsigned long size)
 	shadow_start = PAGE_ALIGN_DOWN(shadow_start);
 	shadow_end = PAGE_ALIGN(shadow_end);
 
-	ret = __kasan_populate_vmalloc(shadow_start, shadow_end);
+	ret = __kasan_populate_vmalloc(shadow_start, shadow_end, gfp_mask);
 	if (ret)
 		return ret;
 
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 3519c4e4f841d..79e6c0e599f5f 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -1977,6 +1977,8 @@ static struct vmap_area *alloc_vmap_area(unsigned long size,
 	if (unlikely(!vmap_initialized))
 		return ERR_PTR(-EBUSY);
 
+	/* Only reclaim behaviour flags are relevant. */
+	gfp_mask = gfp_mask & GFP_RECLAIM_MASK;
 	might_sleep();
 
 	/*
@@ -1989,8 +1991,6 @@ static struct vmap_area *alloc_vmap_area(unsigned long size,
 	 */
 	va = node_alloc(size, align, vstart, vend, &addr, &vn_id);
 	if (!va) {
-		gfp_mask = gfp_mask & GFP_RECLAIM_MASK;
-
 		va = kmem_cache_alloc_node(vmap_area_cachep, gfp_mask, node);
 		if (unlikely(!va))
 			return ERR_PTR(-ENOMEM);
@@ -2040,7 +2040,7 @@ static struct vmap_area *alloc_vmap_area(unsigned long size,
 	BUG_ON(va->va_start < vstart);
 	BUG_ON(va->va_end > vend);
 
-	ret = kasan_populate_vmalloc(addr, size);
+	ret = kasan_populate_vmalloc(addr, size, gfp_mask);
 	if (ret) {
 		free_vmap_area(va);
 		return ERR_PTR(ret);
@@ -4789,7 +4789,7 @@ struct vm_struct **pcpu_get_vm_areas(const unsigned long *offsets,
 
 	/* populate the kasan shadow space */
 	for (area = 0; area < nr_vms; area++) {
-		if (kasan_populate_vmalloc(vas[area]->va_start, sizes[area]))
+		if (kasan_populate_vmalloc(vas[area]->va_start, sizes[area], GFP_KERNEL))
 			goto err_free_shadow;
 	}
 
-- 
2.51.0


^ permalink raw reply related	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2025-09-13 18:59 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2025-09-13 12:25 FAILED: patch "[PATCH] mm/vmalloc, mm/kasan: respect gfp mask in" failed to apply to 6.12-stable tree gregkh
2025-09-13 18:59 ` [PATCH 6.12.y 1/2] kasan: avoid sleepable page allocation from atomic context Sasha Levin
2025-09-13 18:59   ` [PATCH 6.12.y 2/2] mm/vmalloc, mm/kasan: respect gfp mask in kasan_populate_vmalloc() Sasha Levin

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