From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael Kerrisk (man-pages)" Subject: [PATCH 1/3] sched: Make sched_setattr() correctly return -EFBIG Date: Fri, 09 May 2014 16:54:15 +0200 Message-ID: <536CEC17.9070903@gmail.com> References: <536CEAEE.4010609@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <536CEAEE.4010609@gmail.com> Sender: linux-kernel-owner@vger.kernel.org To: Peter Zijlstra Cc: mtk.manpages@gmail.com, lkml , Juri Lelli , Dario Faggioli , Ingo Molnar , "linux-man@vger.kernel.org" List-Id: linux-man@vger.kernel.org From: Michael Kerrisk 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 --- 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; -- 1.9.0