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Mon, 15 Sep 2025 06:40:49 -0700 (PDT) From: "Uladzislau Rezki (Sony)" To: linux-mm@kvack.org, Andrew Morton Cc: Michal Hocko , Baoquan He , LKML , Uladzislau Rezki , Alexander Potapenko , Marco Elver Subject: [PATCH v2 08/10] kmsan: Remove hard-coded GFP_KERNEL flags Date: Mon, 15 Sep 2025 15:40:38 +0200 Message-ID: <20250915134041.151462-9-urezki@gmail.com> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20250915134041.151462-1-urezki@gmail.com> References: <20250915134041.151462-1-urezki@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" kmsan_vmap_pages_range_noflush() allocates its temp s_pages/o_pages arrays with GFP_KERNEL, which may sleep. This is inconsistent with vmalloc() as it will support non-blocking requests later. Plumb gfp_mask through the kmsan_vmap_pages_range_noflush(), so it can use it internally for its demand. Please note, the subsequent __vmap_pages_range_noflush() still uses GFP_KERNEL and can sleep. If a caller runs under reclaim constraints, sleeping is forbidden, it must establish the appropriate memalloc scope API. Cc: Alexander Potapenko Cc: Marco Elver Signed-off-by: Uladzislau Rezki (Sony) --- include/linux/kmsan.h | 6 ++++-- mm/internal.h | 4 ++-- mm/kmsan/shadow.c | 6 +++--- mm/percpu-vm.c | 2 +- mm/vmalloc.c | 26 +++++++++++++++++--------- 5 files changed, 27 insertions(+), 17 deletions(-) diff --git a/include/linux/kmsan.h b/include/linux/kmsan.h index 2b1432cc16d5..e4b34e7a3b11 100644 --- a/include/linux/kmsan.h +++ b/include/linux/kmsan.h @@ -133,6 +133,7 @@ void kmsan_kfree_large(const void *ptr); * @prot: page protection flags used for vmap. * @pages: array of pages. * @page_shift: page_shift passed to vmap_range_noflush(). + * @gfp_mask: gfp_mask to use internally. * * KMSAN maps shadow and origin pages of @pages into contiguous ranges in * vmalloc metadata address range. Returns 0 on success, callers must check @@ -142,7 +143,8 @@ int __must_check kmsan_vmap_pages_range_noflush(unsigne= d long start, unsigned long end, pgprot_t prot, struct page **pages, - unsigned int page_shift); + unsigned int page_shift, + gfp_t gfp_mask); =20 /** * kmsan_vunmap_kernel_range_noflush() - Notify KMSAN about a vunmap. @@ -348,7 +350,7 @@ static inline void kmsan_kfree_large(const void *ptr) =20 static inline int __must_check kmsan_vmap_pages_range_noflush( unsigned long start, unsigned long end, pgprot_t prot, - struct page **pages, unsigned int page_shift) + struct page **pages, unsigned int page_shift, gfp_t gfp_mask) { return 0; } diff --git a/mm/internal.h b/mm/internal.h index 45b725c3dc03..5f3486c1cb83 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -1359,7 +1359,7 @@ size_t splice_folio_into_pipe(struct pipe_inode_info = *pipe, #ifdef CONFIG_MMU void __init vmalloc_init(void); int __must_check vmap_pages_range_noflush(unsigned long addr, unsigned lon= g end, - pgprot_t prot, struct page **pages, unsigned int page_shif= t); + pgprot_t prot, struct page **pages, unsigned int page_shift, gfp_t gfp_ma= sk); unsigned int get_vm_area_page_order(struct vm_struct *vm); #else static inline void vmalloc_init(void) @@ -1368,7 +1368,7 @@ static inline void vmalloc_init(void) =20 static inline int __must_check vmap_pages_range_noflush(unsigned long addr, unsigned lon= g end, - pgprot_t prot, struct page **pages, unsigned int page_shif= t) + pgprot_t prot, struct page **pages, unsigned int page_shift, gfp_t gfp_ma= sk) { return -EINVAL; } diff --git a/mm/kmsan/shadow.c b/mm/kmsan/shadow.c index 54f3c3c962f0..3cd733663100 100644 --- a/mm/kmsan/shadow.c +++ b/mm/kmsan/shadow.c @@ -215,7 +215,7 @@ void kmsan_free_page(struct page *page, unsigned int or= der) =20 int kmsan_vmap_pages_range_noflush(unsigned long start, unsigned long end, pgprot_t prot, struct page **pages, - unsigned int page_shift) + unsigned int page_shift, gfp_t gfp_mask) { unsigned long shadow_start, origin_start, shadow_end, origin_end; struct page **s_pages, **o_pages; @@ -230,8 +230,8 @@ int kmsan_vmap_pages_range_noflush(unsigned long start,= unsigned long end, return 0; =20 nr =3D (end - start) / PAGE_SIZE; - s_pages =3D kcalloc(nr, sizeof(*s_pages), GFP_KERNEL); - o_pages =3D kcalloc(nr, sizeof(*o_pages), GFP_KERNEL); + s_pages =3D kcalloc(nr, sizeof(*s_pages), gfp_mask); + o_pages =3D kcalloc(nr, sizeof(*o_pages), gfp_mask); if (!s_pages || !o_pages) { err =3D -ENOMEM; goto ret; diff --git a/mm/percpu-vm.c b/mm/percpu-vm.c index cd69caf6aa8d..4f5937090590 100644 --- a/mm/percpu-vm.c +++ b/mm/percpu-vm.c @@ -194,7 +194,7 @@ static int __pcpu_map_pages(unsigned long addr, struct = page **pages, int nr_pages) { return vmap_pages_range_noflush(addr, addr + (nr_pages << PAGE_SHIFT), - PAGE_KERNEL, pages, PAGE_SHIFT); + PAGE_KERNEL, pages, PAGE_SHIFT, GFP_KERNEL); } =20 /** diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 5e01c6ac4aca..2d4e22dd04f7 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -671,16 +671,28 @@ int __vmap_pages_range_noflush(unsigned long addr, un= signed long end, } =20 int vmap_pages_range_noflush(unsigned long addr, unsigned long end, - pgprot_t prot, struct page **pages, unsigned int page_shift) + pgprot_t prot, struct page **pages, unsigned int page_shift, + gfp_t gfp_mask) { int ret =3D kmsan_vmap_pages_range_noflush(addr, end, prot, pages, - page_shift); + page_shift, gfp_mask); =20 if (ret) return ret; return __vmap_pages_range_noflush(addr, end, prot, pages, page_shift); } =20 +static int __vmap_pages_range(unsigned long addr, unsigned long end, + pgprot_t prot, struct page **pages, unsigned int page_shift, + gfp_t gfp_mask) +{ + int err; + + err =3D vmap_pages_range_noflush(addr, end, prot, pages, page_shift, gfp_= mask); + flush_cache_vmap(addr, end); + return err; +} + /** * vmap_pages_range - map pages to a kernel virtual address * @addr: start of the VM area to map @@ -696,11 +708,7 @@ int vmap_pages_range_noflush(unsigned long addr, unsig= ned long end, int vmap_pages_range(unsigned long addr, unsigned long end, pgprot_t prot, struct page **pages, unsigned int page_shift) { - int err; - - err =3D vmap_pages_range_noflush(addr, end, prot, pages, page_shift); - flush_cache_vmap(addr, end); - return err; + return __vmap_pages_range(addr, end, prot, pages, page_shift, GFP_KERNEL); } =20 static int check_sparse_vm_area(struct vm_struct *area, unsigned long star= t, @@ -3838,8 +3846,8 @@ static void *__vmalloc_area_node(struct vm_struct *ar= ea, gfp_t gfp_mask, */ flags =3D memalloc_apply_gfp_scope(gfp_mask); do { - ret =3D vmap_pages_range(addr, addr + size, prot, area->pages, - page_shift); + ret =3D __vmap_pages_range(addr, addr + size, prot, area->pages, + page_shift, nested_gfp); if (nofail && (ret < 0)) schedule_timeout_uninterruptible(1); } while (nofail && (ret < 0)); --=20 2.47.3