From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arne Jansen Subject: Re: [PATCH] Btrfs: avoid stack bloat in btrfs_ioctl_fs_info() Date: Wed, 08 Jun 2011 09:10:38 +0200 Message-ID: <4DEF206E.9000600@gmx.net> References: <4DEEF352.7050401@cn.fujitsu.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Cc: "linux-btrfs@vger.kernel.org" To: Li Zefan Return-path: In-Reply-To: <4DEEF352.7050401@cn.fujitsu.com> List-ID: On 08.06.2011 05:58, Li Zefan wrote: > The size of struct btrfs_ioctl_fs_info_args is as big as 1KB, so > don't declare the variable on stack. > > Signed-off-by: Li Zefan > --- > fs/btrfs/ioctl.c | 23 ++++++++++++++--------- > 1 files changed, 14 insertions(+), 9 deletions(-) > > diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c > index ac37040..9705c5c 100644 > --- a/fs/btrfs/ioctl.c > +++ b/fs/btrfs/ioctl.c > @@ -2054,29 +2054,34 @@ static long btrfs_ioctl_rm_dev(struct btrfs_root *root, void __user *arg) > > static long btrfs_ioctl_fs_info(struct btrfs_root *root, void __user *arg) > { > - struct btrfs_ioctl_fs_info_args fi_args; > + struct btrfs_ioctl_fs_info_args *fi_args; > struct btrfs_device *device; > struct btrfs_device *next; > struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices; > + int ret = 0; > > if (!capable(CAP_SYS_ADMIN)) > return -EPERM; > > - fi_args.num_devices = fs_devices->num_devices; > - fi_args.max_id = 0; > - memcpy(&fi_args.fsid, root->fs_info->fsid, sizeof(fi_args.fsid)); > + fi_args = kzalloc(sizeof(*fi_args), GFP_KERNEL); > + if (!fi_args) > + return -ENOMEM; > + > + fi_args->num_devices = fs_devices->num_devices; > + memcpy(&fi_args->fsid, root->fs_info->fsid, sizeof(fi_args->fsid)); > > mutex_lock(&fs_devices->device_list_mutex); > list_for_each_entry_safe(device, next, &fs_devices->devices, dev_list) { > - if (device->devid > fi_args.max_id) > - fi_args.max_id = device->devid; > + if (device->devid > fi_args->max_id) > + fi_args->max_id = device->devid; > } > mutex_unlock(&fs_devices->device_list_mutex); > > - if (copy_to_user(arg, &fi_args, sizeof(fi_args))) > - return -EFAULT; > + if (copy_to_user(arg, fi_args, sizeof(fi_args))) sizeof(*fi_args) will integrate that, thanks :) -Arne > + ret = -EFAULT; > > - return 0; > + kfree(fi_args); > + return ret; > } > > static long btrfs_ioctl_dev_info(struct btrfs_root *root, void __user *arg) > -- 1.7.3.1 > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html