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[94.245.46.49]) by smtp.gmail.com with ESMTPSA id m16sm3932304ljb.47.2019.12.04.14.40.45 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 04 Dec 2019 14:40:45 -0800 (PST) From: Uladzislau Rezki X-Google-Original-From: Uladzislau Rezki Date: Wed, 4 Dec 2019 23:40:37 +0100 To: Andrey Ryabinin Cc: Andrew Morton , Alexander Potapenko , Dmitry Vyukov , kasan-dev@googlegroups.com, Daniel Axtens , Qian Cai , linux-mm@kvack.org, linux-kernel@vger.kernel.org, syzbot+82e323920b78d54aaed5@syzkaller.appspotmail.com Subject: Re: [PATCH 1/2] kasan: fix crashes on access to memory mapped by vm_map_ram() Message-ID: <20191204224037.GA12896@pc636> References: <20191204204534.32202-1-aryabinin@virtuozzo.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191204204534.32202-1-aryabinin@virtuozzo.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > diff --git a/mm/vmalloc.c b/mm/vmalloc.c > index 4d3b3d60d893..a5412f14f57f 100644 > --- a/mm/vmalloc.c > +++ b/mm/vmalloc.c > @@ -1073,6 +1073,7 @@ static struct vmap_area *alloc_vmap_area(unsigned long size, > struct vmap_area *va, *pva; > unsigned long addr; > int purged = 0; > + int ret = -EBUSY; > > BUG_ON(!size); > BUG_ON(offset_in_page(size)); > @@ -1139,6 +1140,10 @@ static struct vmap_area *alloc_vmap_area(unsigned long size, > va->va_end = addr + size; > va->vm = NULL; > > + ret = kasan_populate_vmalloc(addr, size); > + if (ret) > + goto out; > + But it introduces another issues when is CONFIG_KASAN_VMALLOC=y. If the kasan_populate_vmalloc() gets failed for some reason it just leaves the function, that will lead to waste of vmap space. > spin_lock(&vmap_area_lock); > insert_vmap_area(va, &vmap_area_root, &vmap_area_list); > spin_unlock(&vmap_area_lock); > ret = kasan_populate_vmalloc(addr, size); if (ret) { free_vmap_area(va); return ERR_PTR(-EBUSY);; } > @@ -1169,8 +1174,9 @@ static struct vmap_area *alloc_vmap_area(unsigned long size, > pr_warn("vmap allocation for size %lu failed: use vmalloc= to increase size\n", > size); > > +out: > kmem_cache_free(vmap_area_cachep, va); > - return ERR_PTR(-EBUSY); > + return ERR_PTR(ret); > } >