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)))
+ 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
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Arne Jansen
2011-Jun-08 07:10 UTC
Re: [PATCH] Btrfs: avoid stack bloat in btrfs_ioctl_fs_info()
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-- 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
Li Zefan
2011-Jun-08 07:23 UTC
Re: [PATCH] Btrfs: avoid stack bloat in btrfs_ioctl_fs_info()
>> - 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 :) >Oops, what a silly mistake! -- 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