From mboxrd@z Thu Jan 1 00:00:00 1970 From: Waiman Long Subject: Re: [PATCH v4 3/3] btrfs: Use kfree() in btrfs_ioctl_get_subvol_info() Date: Tue, 16 Jun 2020 11:05:22 -0400 Message-ID: <75152002-5f02-04b6-a811-29ef79961e0b@redhat.com> References: <20200616015718.7812-1-longman@redhat.com> <20200616015718.7812-4-longman@redhat.com> <20200616144804.GD27795@twin.jikos.cz> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20200616144804.GD27795@twin.jikos.cz> Content-Language: en-US Sender: target-devel-owner@vger.kernel.org To: dsterba@suse.cz, Andrew Morton , David Howells , Jarkko Sakkinen , James Morris , "Serge E. Hallyn" , Linus Torvalds , Joe Perches , Matthew Wilcox , David Rientjes , Michal Hocko , Johannes Weiner , Dan Carpenter , "Jason A . Donenfeld" , linux-mm@kvack.org, keyrings@vger.kernel.org, linux-kernel@vger.kernel.org, linux-crypto@vger.kernel.org, linux-pm@vger.kernel.org, linux-stm32@st-md-mailman.stormreply.com, linux-amlogic@lists.infradead.org, linux-mediatek@lists.in List-Id: virtualization@lists.linuxfoundation.org On 6/16/20 10:48 AM, David Sterba wrote: > On Mon, Jun 15, 2020 at 09:57:18PM -0400, Waiman Long wrote: >> In btrfs_ioctl_get_subvol_info(), there is a classic case where kzalloc() >> was incorrectly paired with kzfree(). According to David Sterba, there >> isn't any sensitive information in the subvol_info that needs to be >> cleared before freeing. So kfree_sensitive() isn't really needed, >> use kfree() instead. >> >> Reported-by: David Sterba >> Signed-off-by: Waiman Long >> --- >> fs/btrfs/ioctl.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c >> index f1dd9e4271e9..e8f7c5f00894 100644 >> --- a/fs/btrfs/ioctl.c >> +++ b/fs/btrfs/ioctl.c >> @@ -2692,7 +2692,7 @@ static int btrfs_ioctl_get_subvol_info(struct file *file, void __user *argp) >> btrfs_put_root(root); >> out_free: >> btrfs_free_path(path); >> - kfree_sensitive(subvol_info); >> + kfree(subvol_info); > I would rather merge a patch doing to kzfree -> kfree instead of doing > the middle step to switch it to kfree_sensitive. If it would help > integration of your patchset I can push it to the next rc so there are > no kzfree left in the btrfs code. Treewide change like that can take > time so it would be one less problem to care about for you. > Sure, I will move it forward in the patch series. Thanks, Longman