Messages in this thread | | | Date | Fri, 5 Dec 2014 14:41:43 -0800 | From | Tristan Lelong <> | Subject | Re: [PATCH] staging: lustre: fix sparse warning on LPROC_SEQ_FOPS macros |
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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
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