+++ /dev/null
-From stable+bounces-179517-greg=kroah.com@vger.kernel.org Sat Sep 13 20:59:54 2025
-From: Sasha Levin <sashal@kernel.org>
-Date: Sat, 13 Sep 2025 14:59:44 -0400
-Subject: kasan: avoid sleepable page allocation from atomic context
-To: stable@vger.kernel.org
-Cc: Alexander Gordeev <agordeev@linux.ibm.com>, Andrey Ryabinin <ryabinin.a.a@gmail.com>, Harry Yoo <harry.yoo@oracle.com>, Daniel Axtens <dja@axtens.net>, Andrew Morton <akpm@linux-foundation.org>, Sasha Levin <sashal@kernel.org>
-Message-ID: <20250913185945.1514830-1-sashal@kernel.org>
-
-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>
-Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
----
- mm/kasan/shadow.c | 92 +++++++++++++++++++++++++++++++++++++++++++++---------
- 1 file changed, 78 insertions(+), 14 deletions(-)
-
---- a/mm/kasan/shadow.c
-+++ b/mm/kasan/shadow.c
-@@ -292,33 +292,99 @@ void __init __weak kasan_populate_early_
- {
- }
-
-+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
- 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;
-
+++ /dev/null
-From stable+bounces-179518-greg=kroah.com@vger.kernel.org Sat Sep 13 21:00:00 2025
-From: Sasha Levin <sashal@kernel.org>
-Date: Sat, 13 Sep 2025 14:59:45 -0400
-Subject: mm/vmalloc, mm/kasan: respect gfp mask in kasan_populate_vmalloc()
-To: stable@vger.kernel.org
-Cc: "Uladzislau Rezki (Sony)" <urezki@gmail.com>, syzbot+3470c9ffee63e4abafeb@syzkaller.appspotmail.com, Andrey Ryabinin <ryabinin.a.a@gmail.com>, Baoquan He <bhe@redhat.com>, Michal Hocko <mhocko@kernel.org>, Alexander Potapenko <glider@google.com>, Andrey Konovalov <andreyknvl@gmail.com>, Dmitry Vyukov <dvyukov@google.com>, Vincenzo Frascino <vincenzo.frascino@arm.com>, Andrew Morton <akpm@linux-foundation.org>, Sasha Levin <sashal@kernel.org>
-Message-ID: <20250913185945.1514830-2-sashal@kernel.org>
-
-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>
-Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
----
- include/linux/kasan.h | 6 +++---
- mm/kasan/shadow.c | 31 ++++++++++++++++++++++++-------
- mm/vmalloc.c | 8 ++++----
- 3 files changed, 31 insertions(+), 14 deletions(-)
-
---- a/include/linux/kasan.h
-+++ b/include/linux/kasan.h
-@@ -564,7 +564,7 @@ static inline void kasan_init_hw_tags(vo
- #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_
- 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
- 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;
- }
---- a/mm/kasan/shadow.c
-+++ b/mm/kasan/shadow.c
-@@ -335,13 +335,13 @@ static void ___free_pages_bulk(struct pa
- }
- }
-
--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 pa
- 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(unsi
- 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
- 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;
-
---- a/mm/vmalloc.c
-+++ b/mm/vmalloc.c
-@@ -1977,6 +1977,8 @@ static struct vmap_area *alloc_vmap_area
- 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
- */
- 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 @@ retry:
- 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 @@ retry:
-
- /* 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;
- }
-
projects / thirdparty / kernel / stable-queue.git / commitdiff
