From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sahitya Tummala Subject: Re: [PATCH] f2fs: fix use-after-free issue with sbi->stat_info Date: Wed, 26 Dec 2018 09:56:00 +0530 Message-ID: <20181226042600.GA29190@codeaurora.org> References: <1545656812-14695-1-git-send-email-stummala@codeaurora.org> <0938f41e-53ed-6290-9b79-d221b1e64db6@huawei.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <0938f41e-53ed-6290-9b79-d221b1e64db6@huawei.com> Sender: linux-kernel-owner@vger.kernel.org To: Chao Yu Cc: Jaegeuk Kim , linux-f2fs-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org List-Id: linux-f2fs-devel.lists.sourceforge.net On Tue, Dec 25, 2018 at 11:06:45AM +0800, Chao Yu wrote: > On 2018/12/24 21:06, Sahitya Tummala wrote: > > iput() on sbi->node_inode can update sbi->stat_info > > in the below context, if the f2fs_write_checkpoint() > > has failed with error. > > > > f2fs_balance_fs_bg+0x1ac/0x1ec > > f2fs_write_node_pages+0x4c/0x260 > > do_writepages+0x80/0xbc > > __writeback_single_inode+0xdc/0x4ac > > writeback_single_inode+0x9c/0x144 > > write_inode_now+0xc4/0xec > > iput+0x194/0x22c > > f2fs_put_super+0x11c/0x1e8 > > generic_shutdown_super+0x70/0xf4 > > kill_block_super+0x2c/0x5c > > kill_f2fs_super+0x44/0x50 > > deactivate_locked_super+0x60/0x8c > > deactivate_super+0x68/0x74 > > cleanup_mnt+0x40/0x78 > > > > Fix this by moving f2fs_destroy_stats() further below iput(). > > > > Signed-off-by: Sahitya Tummala > > --- > > fs/f2fs/super.c | 9 ++++++--- > > 1 file changed, 6 insertions(+), 3 deletions(-) > > > > diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c > > index e184ad4e..df41a3a 100644 > > --- a/fs/f2fs/super.c > > +++ b/fs/f2fs/super.c > > @@ -1058,9 +1058,6 @@ static void f2fs_put_super(struct super_block *sb) > > f2fs_write_checkpoint(sbi, &cpc); > > } > > > > - /* f2fs_write_checkpoint can update stat informaion */ > > - f2fs_destroy_stats(sbi); > > The code order in error path of fill_super is almost the same as the one of > put_super, could you please check that as well? > Thanks Chao, for pointing it out. Yes, the same issue exists in error path of fill_super as well. I will fix it. > Thanks, > > > - > > /* > > * normally superblock is clean, so we need to release this. > > * In addition, EIO will skip do checkpoint, we need this as well. > > @@ -1080,6 +1077,12 @@ static void f2fs_put_super(struct super_block *sb) > > iput(sbi->node_inode); > > iput(sbi->meta_inode); > > > > + /* > > + * iput() can update stat information, if f2fs_write_checkpoint() > > + * above failed with error. > > + */ > > + f2fs_destroy_stats(sbi); > > + > > /* destroy f2fs internal modules */ > > f2fs_destroy_node_manager(sbi); > > f2fs_destroy_segment_manager(sbi); > > > -- -- Sent by a consultant of the Qualcomm Innovation Center, Inc. The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.