From: Arne Jansen <sensille@gmx.net>
To: Li Zefan <lizf@cn.fujitsu.com>
Cc: "linux-btrfs@vger.kernel.org" <linux-btrfs@vger.kernel.org>
Subject: Re: [PATCH] Btrfs: avoid stack bloat in btrfs_ioctl_fs_info()
Date: Wed, 08 Jun 2011 09:10:38 +0200 [thread overview]
Message-ID: <4DEF206E.9000600@gmx.net> (raw)
In-Reply-To: <4DEEF352.7050401@cn.fujitsu.com>
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 <lizf@cn.fujitsu.com>
> ---
> 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
next prev parent reply other threads:[~2011-06-08 7:10 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-06-08 3:58 [PATCH] Btrfs: avoid stack bloat in btrfs_ioctl_fs_info() Li Zefan
2011-06-08 7:10 ` Arne Jansen [this message]
2011-06-08 7:23 ` Li Zefan
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=4DEF206E.9000600@gmx.net \
--to=sensille@gmx.net \
--cc=linux-btrfs@vger.kernel.org \
--cc=lizf@cn.fujitsu.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).