From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-lj1-f177.google.com (mail-lj1-f177.google.com [209.85.208.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9AAAA233737 for ; Tue, 11 Mar 2025 10:25:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.208.177 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741688706; cv=none; b=UeoSpHIEmk850zirTRN4wi2auwatEcfHQutMfug7A4hLyXBHx4U9fpgtKGHzI9pwV4tplO2OUX70VZYRhN3kQw1JDXVxnRgbeiMxLwNZZPD6BjfU/QKOojLyDnxZVmTz3culv6LHAHlOHoncx7uR4YwTnS48nw6PK9i9RnMo/Ug= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741688706; c=relaxed/simple; bh=eDgq6JXqoZ8TDqPqb3LsjrjdX0fEl/p8NNVfCpfdP/g=; h=From:Date:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=HC+5VHjQYfwfmv0/o+y1H8WCI9EPx8+s8WkotC5L9qE75EiFrZ4PeKFez4vNSZ8Z3xuYOQjbjADVHYTuPSNu+htkLs7fqrCssElVFvmW003FfNGEJxDn8e8i4bKa+SFY6S3Unlr3OuoFGMzvS7UnStAR7K9yolX+F6wea8xJnPM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=XoPF/1sN; arc=none smtp.client-ip=209.85.208.177 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="XoPF/1sN" Received: by mail-lj1-f177.google.com with SMTP id 38308e7fff4ca-30c05fd126cso25246171fa.3 for ; Tue, 11 Mar 2025 03:25:04 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1741688703; x=1742293503; darn=lists.linux.dev; h=in-reply-to:content-transfer-encoding:content-disposition :mime-version:references:message-id:subject:cc:to:date:from:from:to :cc:subject:date:message-id:reply-to; bh=yQ9QHu9OwuR/HOCYxmuFMkfIcaT2lB/BHKzVqZDxMW4=; b=XoPF/1sNd6SyTvXGvkUGr14zFyAhzVEcmd5B0+vQ6bHSqDQdxw5AIoYcKxnVcf5BKC 2hF1OC72VANW1hLPe1Kj3XeIaJIOr6eubzeEwkTGRfpXZ8KCd5rmGYnZBabV5xkocw1f Wb5YfeNgAjoaTEyaYqmcKDzPuXAH39gJvDAgVcPHBYCCbKxce2NqNlh9cRYvmgptFtBY z4j7cRfcd2cknJPdejIf+3YHmQubrbfXHk2mwRU5MLIUZLo83zCkltPpv+eckaGRUQhz wpYbAVVV9vbp3btfkadO8mSv3gafM+Fl7HY/Zd7r0MPpA0Zo/KD9w18Z7ouP9JJCUIbF ej6A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1741688703; x=1742293503; h=in-reply-to:content-transfer-encoding:content-disposition :mime-version:references:message-id:subject:cc:to:date:from :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=yQ9QHu9OwuR/HOCYxmuFMkfIcaT2lB/BHKzVqZDxMW4=; b=ngw4D47z6S0YMI7NlX63dw8mNsFLILqnYLj4Q9QOyIAvHuHkbvRuxrLMxjNqnDq0LT BZKivvOQJkYI1SLGgq2Sw1DPGDeY6rGl8Gq+o7pK78JExiUrd4KUpHXGFy+ga05BAhuV xfn1teEWK6VFtyPOHOZtZd1FsKvZVobVL/2S7As6ykIlk1mcwUJVt0T4ynLZgr1JF9fr e9EQBgVHyqhsuhsQ+H5/nnyj0fp8OwPWI7g0XRdxz6+gzQtQBafoonwxQ0sH4zWxF/lV EybsUHlsvvvXqvSPf4L01LecaIXDQ0cdxZ0IDtPTaEkMdnzCkomGmd5RQYNt7urh36Jg K1Gg== X-Forwarded-Encrypted: i=1; AJvYcCUnTOG+1VcxJkjQDNLpTpGFMU27lXIvcRgaxXUHgo4q7nbs6lQbqSPhE8c8/uk6FzTgzbr9Vsw=@lists.linux.dev X-Gm-Message-State: AOJu0YwXk19UAtfQHBypGxK8E0srxOmiJcfAFLCTqOiQKs8QiRbuaNRl WaHs8/F9e+ai9+pTw5yL1hbMF/h9uRP9GC/1JDNnaAK5ldzkqX3F X-Gm-Gg: ASbGncupyX9dm4ZgiDDrkfYpBcB10ItBEYvR+Kv1AR5JJ3saC8w6YrsJtEaqQQ4gEpp PxdTrB3cYR6ozloHg1l0oJv6HUVze4XZg3k+WlLkxBDMG+gs6yTEBVUZ7/QctG5BH7L2hTXYb6k GeFR6RtczqrO7fVicj/j/hZK5RQSYErHokVgVQtc1SfxRaet9eMBzwH66Tetupnm/Z3+/UbNt+V l39ntW4+6cfM0w/xBxSYysYMeLh9+1M0H1dDgE0DmHcTK1vxIybquKA9fc7OG/y+Sg1ydPyPdTW 3W0STVzVN8mmSyA/WgydeDpmxSGLix0Q/wqgOGm58EFhvpIf2TI/vUJL3Qxz2ufIC1Y= X-Google-Smtp-Source: AGHT+IHZ491cWXLpS+dqT3PInxZGFT9Hawkj2mUnUkO88aGsnJ/1oIGYlFx6eiFALRnYsmrDGwS0fw== X-Received: by 2002:a2e:bea2:0:b0:30b:bfca:bbf2 with SMTP id 38308e7fff4ca-30bf44e60d1mr57376651fa.7.1741688702288; Tue, 11 Mar 2025 03:25:02 -0700 (PDT) Received: from pc636 (host-95-203-6-24.mobileonline.telia.com. [95.203.6.24]) by smtp.gmail.com with ESMTPSA id 38308e7fff4ca-30bffe3a2b5sm14425671fa.32.2025.03.11.03.25.01 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 11 Mar 2025 03:25:01 -0700 (PDT) From: Uladzislau Rezki X-Google-Original-From: Uladzislau Rezki Date: Tue, 11 Mar 2025 11:24:58 +0100 To: liuye , Andrew Morton Cc: Uladzislau Rezki , Andrew Morton , oe-lkp@lists.linux.dev, lkp@intel.com, Christop Hellwig , linux-mm@kvack.org Subject: Re: [linux-next:master] [mm/vmalloc] ff6f2b81ea: WARNING:at_kernel/fork.c:#vm_area_init_from Message-ID: References: <202503101629.7289b1-lkp@intel.com> Precedence: bulk X-Mailing-List: oe-lkp@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: On Tue, Mar 11, 2025 at 03:26:59PM +0800, liuye wrote: > > > 在 2025/3/11 00:52, Uladzislau Rezki 写道: > > Hello, Andrew, Liu Ye. > > > >> > >> Hello, > >> > >> kernel test robot noticed "WARNING:at_kernel/fork.c:#vm_area_init_from" on: > >> > >> commit: ff6f2b81eaa8a9fe5d158c6e7b1e58d3929c32c1 ("mm/vmalloc: move free_vm_area(area) from the __vmalloc_area_node function to the __vmalloc_node_range_noprof function") > >> https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git master > >> > >> [test failed on linux-next/master 0a2f889128969dab41861b6e40111aa03dc57014] > >> > >> in testcase: trinity > >> version: > >> with following parameters: > >> > >> runtime: 300s > >> group: group-02 > >> nr_groups: 5 > >> > >> > >> > >> config: x86_64-randconfig-101-20250306 > >> compiler: gcc-12 > >> test machine: qemu-system-x86_64 -enable-kvm -cpu SandyBridge -smp 2 -m 16G > >> > >> (please refer to attached dmesg/kmsg for entire log/backtrace) > >> > >> > >> +-------------------------------------------------------------+------------+------------+ > >> | | fb8faf4337 | ff6f2b81ea | > >> +-------------------------------------------------------------+------------+------------+ > >> | boot_successes | 9 | 0 | > >> | boot_failures | 0 | 6 | > >> | WARNING:at_kernel/fork.c:#vm_area_init_from | 0 | 6 | > >> | RIP:vm_area_init_from | 0 | 6 | > >> | BUG:KASAN:slab-use-after-free_in__vmalloc_node_range_noprof | 0 | 5 | > >> | WARNING:at_mm/vmalloc.c:#remove_vm_area | 0 | 5 | > >> | RIP:remove_vm_area | 0 | 5 | > >> | kernel_BUG_at_mm/vmalloc.c | 0 | 5 | > >> | Oops:invalid_opcode:#[##]PREEMPT_KASAN | 0 | 5 | > >> | RIP:__vmalloc_node_range_noprof | 0 | 5 | > >> | Kernel_panic-not_syncing:Fatal_exception | 0 | 5 | > >> +-------------------------------------------------------------+------------+------------+ > >> > > The patch that is in question, indeed, looks buggy. At least i can see > > how a use-after-free can occur: > > > > > > static void *__vmalloc_area_node(...) > > ... > > fail: > > vfree(area->addr); > > return NULL; > > } > > > > > > > > ... > > ret = __vmalloc_area_node(area, gfp_mask, prot, shift, node); > > if (!ret) { > > free_vm_area(area); > > goto fail; > > } > > ... > > > > > > vfree() - __also__ frees "vm_struct" where "area" points to. A NULL is > > returned and free_vm_area() is invoked one more time on already freed > > "area". > > > > Probably it is better to drop the below patch: > > > > ff6f2b81eaa8a9fe5d158c6e7b1e58d3929c32c1 ("mm/vmalloc: move free_vm_area(area) from the __vmalloc_area_node function to the __vmalloc_node_range_noprof function") > > > > If drop this commit, then the two “goto fail; ”in the __vmalloc_area_node function will cause area memory leaks in the __vmalloc_area_node function when returning. > It does not leak. On a fail case we release everything including "area": fail: vfree(area->addr); return NULL; this is how vfree() works. > Perhaps the following changes should be added. > > If the following changes should fix all issues I will send a new patch. > > diff --git a/mm/vmalloc.c b/mm/vmalloc.c > index 61981ee1c9d2..1826f3d70885 100644 > --- a/mm/vmalloc.c > +++ b/mm/vmalloc.c > @@ -3697,7 +3697,7 @@ static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask, > warn_alloc(gfp_mask, NULL, > "vmalloc error: size %lu, failed to allocate pages", > area->nr_pages * PAGE_SIZE); > - goto fail; > + return NULL; > } > > /* > @@ -3725,14 +3725,10 @@ static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask, > warn_alloc(gfp_mask, NULL, > "vmalloc error: size %lu, failed to map pages", > area->nr_pages * PAGE_SIZE); > - goto fail; > + return NULL; > } > > return area->addr; > - > -fail: > - vfree(area->addr); > - return NULL; > } > It is better to drop the patch. It does not fix anything, instead it has introduced a degrade. -- Uladzislau Rezki