From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 159173AFB07; Sat, 17 Oct 2026 17:29:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792258146; cv=none; b=B1Zv2gIIQJPh5aXiXwTn8Cbqd7XhBu65d2v8OlS7728zgSnVcGy31BvdoXc1RrvvT6WrGPiCNIcHrOJFnBWHQklZfHL9xAj14SJMQp0tslHGu9yLbj2DfG4bAQDDxmJpmVwg3iJhUOzcG7DOJUOZSTgmB06WRfsYjd/VFTu6pGs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792258146; c=relaxed/simple; bh=LBAv8n5qiTgRQa5W1SW/WyHR7rPq4uC+nI/K0+k8aIw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=gonK/RQtJ8GZSAEoa19rtrhbOrshD4VmBoNcgDNw2SmvqbPFHFpxyqZF4VsXgUVdKQZaufrfE0RGOD0371dU+Yw8q9akzQ82TWckhxUaYI4XM4mlqxOHT1QsJBtMmjU7mJw2QNTKFwmNs3TRtmyM4aX5FHbZrgLKhoG8bbP24aI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=CiQdU//N; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="CiQdU//N" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 09DAF1F000C4; Sat, 17 Oct 2026 17:29:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1792258144; bh=M8UHPvHdFuZCsDFXVtbKTR9K5CUQ20069ZWm+FuS7d4=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=CiQdU//NSlU12y+6wdmQIF0yFj4g2iVcnD94nSxrO+7yqBJYHFL1WpbvQdSf1lDJ1 bwcYQbMTbsANFwNmaUbHhTweW3r2OZup+imhlxHm0BwwsTfZbMMuKtaR6sMmpcZGSQ W9zpkQK3q96UBcWFTtDKEWM07XpCVbiCiUXVYkTg= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, "Uladzislau Rezki (Sony)" , syzbot+3470c9ffee63e4abafeb@syzkaller.appspotmail.com, Andrey Ryabinin , Baoquan He , Michal Hocko , Alexander Potapenko , Andrey Konovalov , Dmitry Vyukov , Vincenzo Frascino , Andrew Morton , Sasha Levin Subject: [PATCH 6.6 0786/1674] mm/vmalloc, mm/kasan: respect gfp mask in kasan_populate_vmalloc() Date: Sat, 17 Oct 2026 17:50:58 +0200 Message-ID: <20261017160451.278766319@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261017160431.119607952@linuxfoundation.org> References: <20261017160431.119607952@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Uladzislau Rezki (Sony) [ 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) Reported-by: syzbot+3470c9ffee63e4abafeb@syzkaller.appspotmail.com Reviewed-by: Andrey Ryabinin Cc: Baoquan He Cc: Michal Hocko Cc: Alexander Potapenko Cc: Andrey Konovalov Cc: Dmitry Vyukov Cc: Vincenzo Frascino Cc: Signed-off-by: Andrew Morton Signed-off-by: Sasha Levin --- include/linux/kasan.h | 6 +++--- mm/kasan/shadow.c | 31 ++++++++++++++++++++++++------- mm/vmalloc.c | 4 ++-- 3 files changed, 29 insertions(+), 12 deletions(-) diff --git a/include/linux/kasan.h b/include/linux/kasan.h index 92bc6bfde6034..d0664f6a8a156 100644 --- a/include/linux/kasan.h +++ b/include/linux/kasan.h @@ -382,7 +382,7 @@ 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); @@ -393,7 +393,7 @@ 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; } @@ -438,7 +438,7 @@ kasan_unpoison_vmap_areas(struct vm_struct **vms, int nr_vms, 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 53ba9953f6bb4..d4e568ecd183f 100644 --- a/mm/kasan/shadow.c +++ b/mm/kasan/shadow.c @@ -354,13 +354,13 @@ 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_array(GFP_KERNEL, nr_pages, pages); + nr_populated = alloc_pages_bulk_array(gfp_mask, nr_pages, pages); if (!nr_populated) { ___free_pages_bulk(page_array, nr_total - nr_pages); return -ENOMEM; @@ -372,25 +372,42 @@ 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; @@ -404,7 +421,7 @@ 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; @@ -433,7 +450,7 @@ 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 3681f0207b218..11ae4bb25fbba 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -1677,7 +1677,7 @@ 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); @@ -4207,7 +4207,7 @@ 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; } -- 2.53.0