As far as I know I don't have any lock around copy_to_user().
The user makes an IOCTL call to the module. The module tries to copy the
IP account table to the user but fails and returns -EINVAL to the
client.
I have cleaned the code and put it at http://olsson.tm/ipaccount/.
ipacc.c - The module
ipaccount.c - The client
Thanks,
Daniel
"Richard B. Johnson" wrote:
>
> On Tue, 20 Jun 2000, Daniel Olsson wrote:
> [SNIPPED...]
> >
> > My problem is that I try to send the accounting table to a user program
> > by an IOCTL call but copy_to_user fails. I have found that copy_to_user
> > fails if the size is > 2976 bytes. I allocate the memory with malloc in
> > the user process and the printf("%p",ptr)/printk("%p",ptr) pair shows
> > that the pointer to the user space memory is correct in the module. Am I
> > doing something wrong?
> >
> > Kind regards,
> > Daniel
> >
>
> Are you trying to copy_to_user() under any kind of a lock? Make sure
> the user can page-fault, remove any locks before the copy_to_user().
>
> I routinely copy 1 - 2 megabyte images to user-space with no problem.
>
> Cheers,
> Dick Johnson
>
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