Re: [HPDD-discuss] [PATCH] staging: lustre: fix sparse warning on LPROC_SEQ_FOPS macros
On Fri, Dec 05, 2014 at 01:27:23PM -0800, Greg KH wrote:
On Fri, Dec 05, 2014 at 12:03:47AM -0800, Tristan Lelong wrote:
> static ssize_t
> -fld_proc_hash_seq_write(struct file *file, const char *buffer,
> - size_t count, loff_t *off)
> +fld_proc_hash_seq_write(struct file *file,
> + const char __user *buffer,
> + size_t count, loff_t *off)
> {
> struct lu_client_fld *fld;
> struct lu_fld_hash *hash = NULL;
> + char name[80];
> int i;
>
> + if (count > 80)
> + return -ENAMETOOLONG;
> +
> + if (copy_from_user(name, buffer, count) != 0)
> + return -EFAULT;
How was this code ever working before?
I have no idea, and was actually surprised that this was there.
And I know Joe asked, but how do you know that 80 is ok? And why on the
stack?
80 is the sizeof(struct lu_fld_hash.fh_name) and there is no define for that.
A few other structure members are using this 80 value internally, and as I told
Joe, I will analyze if they are all related and submit a patch to use a define instead.
Shouldn't you just compare count to strlen(fld_hash[i].fh_name)? like you
do later on?
This is actually done in the for loop already. I first compare with the maximum size,
then the loop use the strlen of each entries in the table, and finally does the strncmp.
Anyway, I don't like large stack variables like this, can you make it
dynamic instead?
I can definitely do this with a kmalloc, I'll submit a v2 tonight.
Thanks