From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 72542E95A61 for ; Sat, 7 Oct 2023 12:02:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1343895AbjJGMCY (ORCPT ); Sat, 7 Oct 2023 08:02:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43250 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344003AbjJGMCM (ORCPT ); Sat, 7 Oct 2023 08:02:12 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9BAE3138 for ; Sat, 7 Oct 2023 05:01:41 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C87A4C433C8; Sat, 7 Oct 2023 12:01:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1696680093; bh=UP/11KOVXhMDlkTzu3apHhL414ZgjdQ0NC2bI3aRAL4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=wRQ39Ujp2QKYz8SnmeF41Q1/lGsdt90hpVqxZRn63UQIqPXNgbJ31hDNDn6+VFbVn 6x5UHrzrgoorTRyw/d5AqNBUwqPFnX/bWE2o1UBsO7juTp++z+VjfS7baIGr4+mWON 6Z8tp2WOUI+e8fNT3yhWH2Ixzg9+YuYh7+lFTsro= Date: Sat, 7 Oct 2023 14:01:30 +0200 From: Greg KH To: Kassey Li Cc: gregkh@google.com, cmllamas@google.com, surenb@google.com, arve@android.com, joel@joelfernandes.org, brauner@kernel.org, tkjos@android.com, maco@android.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] binder: add mutex_lock for mmap and NULL when free Message-ID: <2023100715-crudely-grafting-6193@gregkh> References: <20231007114524.76969-1-quic_yingangl@quicinc.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20231007114524.76969-1-quic_yingangl@quicinc.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Oct 07, 2023 at 07:45:24PM +0800, Kassey Li wrote: > - Enforce alloc->mutex in binder_alloc_mmap_handler when add the entry to > list. > > - Assign the freed pages/page_ptr to NULL to catch possible use after free > with NULL pointer access. > > Fixes: 19c987241ca1 ("binder: separate out binder_alloc functions") > Fixes: f2517eb76f1f ("android: binder: Add global lru shrinker to binder") > Signed-off-by: Kassey Li > --- > drivers/android/binder_alloc.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/drivers/android/binder_alloc.c b/drivers/android/binder_alloc.c > index e3db8297095a..c7d126e04343 100644 > --- a/drivers/android/binder_alloc.c > +++ b/drivers/android/binder_alloc.c > @@ -775,6 +775,7 @@ int binder_alloc_mmap_handler(struct binder_alloc *alloc, > } > > buffer->user_data = alloc->buffer; > + mutex_lock(&alloc->mutex); > list_add(&buffer->entry, &alloc->buffers); > buffer->free = 1; > binder_insert_free_buffer(alloc, buffer); > @@ -782,7 +783,7 @@ int binder_alloc_mmap_handler(struct binder_alloc *alloc, > > /* Signal binder_alloc is fully initialized */ > binder_alloc_set_vma(alloc, vma); > - > + mutex_unlock(&alloc->mutex); > return 0; > > err_alloc_buf_struct_failed: > @@ -856,9 +857,11 @@ void binder_alloc_deferred_release(struct binder_alloc *alloc) > __func__, alloc->pid, i, page_addr, > on_lru ? "on lru" : "active"); > __free_page(alloc->pages[i].page_ptr); > + alloc->pages[i].page_ptr = NULL; > page_count++; > } > kfree(alloc->pages); > + alloc->pages = NULL; > } > mutex_unlock(&alloc->mutex); > if (alloc->mm) > -- > 2.25.1 > Hi, This is the friendly patch-bot of Greg Kroah-Hartman. You have sent him a patch that has triggered this response. He used to manually respond to these common problems, but in order to save his sanity (he kept writing the same thing over and over, yet to different people), I was created. Hopefully you will not take offence and will fix the problem in your patch and resubmit it so that it can be accepted into the Linux kernel tree. You are receiving this message because of the following common error(s) as indicated below: - This looks like a new version of a previously submitted patch, but you did not list below the --- line any changes from the previous version. Please read the section entitled "The canonical patch format" in the kernel file, Documentation/process/submitting-patches.rst for what needs to be done here to properly describe this. - You have marked a patch with a "Fixes:" tag for a commit that is in an older released kernel, yet you do not have a cc: stable line in the signed-off-by area at all, which means that the patch will not be applied to any older kernel releases. To properly fix this, please follow the documented rules in the Documentation/process/stable-kernel-rules.rst file for how to resolve this. If you wish to discuss this problem further, or you have questions about how to resolve this issue, please feel free to respond to this email and Greg will reply once he has dug out from the pending patches received from other developers. thanks, greg k-h's patch email bot