Messages in this thread Patch in this message | | | From | H Hartley Sweeten <> | Date | Fri, 23 Sep 2011 14:02:27 -0500 | Subject | RE: [PATCH] btrfs/ioctl.c: quiet sparse warnings |
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On Friday, September 23, 2011 11:16 AM, Joe Perches wrote: > On Fri, 2011-09-23 at 11:07 -0700, H Hartley Sweeten wrote: >> Quiet the following sparse warnings: > [] >> diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c > [] >> @@ -2705,7 +2705,7 @@ long btrfs_ioctl_space_info(struct btrfs_root *root, void __user *arg) >> up_read(&info->groups_sem); >> } >> >> - user_dest = (struct btrfs_ioctl_space_info *) >> + user_dest = (struct btrfs_ioctl_space_info __user *) >> (arg + sizeof(struct btrfs_ioctl_space_args)); > > user_dest = arg; > user_dest++; > > ?
That produces a new sparse warning:
fs/btrfs/ioctl.c: In function ‘btrfs_ioctl_space_info’: fs/btrfs/ioctl.c:2708: warning: ‘user_dest’ may be used uninitialized in this function
I guess user_dest could be set at the start of the function. This would also remove the cast of arg in the first copy_from_user.
Something like this:
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diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index 970977a..9e7e5dc 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -2599,13 +2599,13 @@ static void get_block_group_info(struct list_head *groups_list, } } -long btrfs_ioctl_space_info(struct btrfs_root *root, void __user *arg) +static long btrfs_ioctl_space_info(struct btrfs_root *root, void __user *arg) { struct btrfs_ioctl_space_args space_args; struct btrfs_ioctl_space_info space; struct btrfs_ioctl_space_info *dest; struct btrfs_ioctl_space_info *dest_orig; - struct btrfs_ioctl_space_info __user *user_dest; + struct btrfs_ioctl_space_info __user *user_dest = arg; struct btrfs_space_info *info; u64 types[] = {BTRFS_BLOCK_GROUP_DATA, BTRFS_BLOCK_GROUP_SYSTEM, @@ -2617,9 +2617,7 @@ long btrfs_ioctl_space_info(struct btrfs_root *root, void __user *arg) u64 slot_count = 0; int i, c; - if (copy_from_user(&space_args, - (struct btrfs_ioctl_space_args __user *)arg, - sizeof(space_args))) + if (copy_from_user(&space_args, user_dest, sizeof(space_args))) return -EFAULT; for (i = 0; i < num_types; i++) { @@ -2705,8 +2703,7 @@ long btrfs_ioctl_space_info(struct btrfs_root *root, void __user *arg) up_read(&info->groups_sem); } - user_dest = (struct btrfs_ioctl_space_info *) - (arg + sizeof(struct btrfs_ioctl_space_args)); + user_dest++; if (copy_to_user(user_dest, dest_orig, alloc_size)) ret = -EFAULT;
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