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SubjectRe: [PATCH 1/3] sched: Make sched_setattr() correctly return -EFBIG
Peter,

In the title of this patch, EFBIG should have been E2BIG. Shall
I resubmit a corrected version?

Cheers,

Michael

On 05/09/2014 04:54 PM, Michael Kerrisk (man-pages) wrote:
> From: Michael Kerrisk <mtk.manpages@gmail.com>
>
> The documented[1] behavior of sched_attr() in your proposed man page text is:
>
> sched_attr::size must be set to the size of the structure, as in
> sizeof(struct sched_attr), if the provided structure is smaller
> than the kernel structure, any additional fields are assumed
> '0'. If the provided structure is larger than the kernel structure,
> the kernel verifies all additional fields are '0' if not the
> syscall will fail with -E2BIG.
>
> As currently implemented, sched_copy_attr() returns -EFBIG for
> for this case, but the logic in sys_sched_setattr() converts that
> error to -EFAULT. This patch fixes the behavior.
>
> [1] http://thread.gmane.org/gmane.linux.kernel/1615615/focus=1697760
>
> Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
> ---
> kernel/sched/core.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/kernel/sched/core.c b/kernel/sched/core.c
> index 268a45e..6c9ce28 100644
> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -3650,8 +3650,9 @@ SYSCALL_DEFINE3(sched_setattr, pid_t, pid, struct sched_attr __user *, uattr,
> if (!uattr || pid < 0 || flags)
> return -EINVAL;
>
> - if (sched_copy_attr(uattr, &attr))
> - return -EFAULT;
> + retval = sched_copy_attr(uattr, &attr);
> + if (retval)
> + return retval;
>
> rcu_read_lock();
> retval = -ESRCH;
>


--
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/


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