[git pull] scheduler fixes

Ingo Molnar
2009-03-03T21:03:17Z

Linus,

Please pull the latest sched-fixes-for-linus git tree from:

git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip.git sched-fixes-for-linus

Thanks,

Ingo

------------------>
Dhaval Giani (1):
sched: don't allow setuid to succeed if the user does not have rt bandwidth

Hiroshi Shimamoto (1):
sched_rt: don't start timer when rt bandwidth disabled

include/linux/sched.h | 4 ++++
kernel/sched.c | 15 ++++++++++++---
kernel/sys.c | 31 ++++++++++++++++++++-----------
kernel/user.c | 18 ++++++++++++++++++
4 files changed, 54 insertions(+), 14 deletions(-)

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 8981e52..8c216e0 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -2291,9 +2291,13 @@ extern long sched_group_rt_runtime(struct task_group *tg);
extern int sched_group_set_rt_period(struct task_group *tg,
long rt_period_us);
extern long sched_group_rt_period(struct task_group *tg);
+extern int sched_rt_can_attach(struct task_group *tg, struct task_struct *tsk);
#endif
#endif

+extern int task_can_switch_user(struct user_struct *up,
+ struct task_struct *tsk);
+
#ifdef CONFIG_TASK_XACCT
static inline void add_rchar(struct task_struct *tsk, ssize_t amt)
{
diff --git a/kernel/sched.c b/kernel/sched.c
index 410eec4..8e2558c 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -223,7 +223,7 @@ static void start_rt_bandwidth(struct rt_bandwidth *rt_b)
{
ktime_t now;

- if (rt_bandwidth_enabled() && rt_b->rt_runtime == RUNTIME_INF)
+ if (!rt_bandwidth_enabled() || rt_b->rt_runtime == RUNTIME_INF)
return;

if (hrtimer_active(&rt_b->rt_period_timer))
@@ -9224,6 +9224,16 @@ static int sched_rt_global_constraints(void)

return ret;
}
+
+int sched_rt_can_attach(struct task_group *tg, struct task_struct *tsk)
+{
+ /* Don't accept realtime tasks when there is no way for them to run */
+ if (rt_task(tsk) && tg->rt_bandwidth.rt_runtime == 0)
+ return 0;
+
+ return 1;
+}
+
#else /* !CONFIG_RT_GROUP_SCHED */
static int sched_rt_global_constraints(void)
{
@@ -9317,8 +9327,7 @@ cpu_cgroup_can_attach(struct cgroup_subsys *ss, struct cgroup *cgrp,
struct task_struct *tsk)
{
#ifdef CONFIG_RT_GROUP_SCHED
- /* Don't accept realtime tasks when there is no way for them to run */
- if (rt_task(tsk) && cgroup_tg(cgrp)->rt_bandwidth.rt_runtime == 0)
+ if (!sched_rt_can_attach(cgroup_tg(cgrp), tsk))
return -EINVAL;
#else
/* We don't support RT-tasks being in separate groups */
diff --git a/kernel/sys.c b/kernel/sys.c
index f145c41..37f458e 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -559,7 +559,7 @@ error:
abort_creds(new);
return retval;
}
-
+
/*
* change the user struct in a credentials set to match the new UID
*/
@@ -571,6 +571,11 @@ static int set_user(struct cred *new)
if (!new_user)
return -EAGAIN;

+ if (!task_can_switch_user(new_user, current)) {
+ free_uid(new_user);
+ return -EINVAL;
+ }
+
if (atomic_read(&new_user->processes) >=
current->signal->rlim[RLIMIT_NPROC].rlim_cur &&
new_user != INIT_USER) {
@@ -631,10 +636,11 @@ SYSCALL_DEFINE2(setreuid, uid_t, ruid, uid_t, euid)
goto error;
}

- retval = -EAGAIN;
- if (new->uid != old->uid && set_user(new) < 0)
- goto error;
-
+ if (new->uid != old->uid) {
+ retval = set_user(new);
+ if (retval < 0)
+ goto error;
+ }
if (ruid != (uid_t) -1 ||
(euid != (uid_t) -1 && euid != old->uid))
new->suid = new->euid;
@@ -680,9 +686,10 @@ SYSCALL_DEFINE1(setuid, uid_t, uid)
retval = -EPERM;
if (capable(CAP_SETUID)) {
new->suid = new->uid = uid;
- if (uid != old->uid && set_user(new) < 0) {
- retval = -EAGAIN;
- goto error;
+ if (uid != old->uid) {
+ retval = set_user(new);
+ if (retval < 0)
+ goto error;
}
} else if (uid != old->uid && uid != new->suid) {
goto error;
@@ -734,11 +741,13 @@ SYSCALL_DEFINE3(setresuid, uid_t, ruid, uid_t, euid, uid_t, suid)
goto error;
}

- retval = -EAGAIN;
if (ruid != (uid_t) -1) {
new->uid = ruid;
- if (ruid != old->uid && set_user(new) < 0)
- goto error;
+ if (ruid != old->uid) {
+ retval = set_user(new);
+ if (retval < 0)
+ goto error;
+ }
}
if (euid != (uid_t) -1)
new->euid = euid;
diff --git a/kernel/user.c b/kernel/user.c
index 3551ac7..6a9b696 100644
--- a/kernel/user.c
+++ b/kernel/user.c
@@ -362,6 +362,24 @@ static void free_user(struct user_struct *up, unsigned long flags)

#endif

+#if defined(CONFIG_RT_GROUP_SCHED) && defined(CONFIG_USER_SCHED)
+/*
+ * We need to check if a setuid can take place. This function should be called
+ * before successfully completing the setuid.
+ */
+int task_can_switch_user(struct user_struct *up, struct task_struct *tsk)
+{
+
+ return sched_rt_can_attach(up->tg, tsk);
+
+}
+#else
+int task_can_switch_user(struct user_struct *up, struct task_struct *tsk)
+{
+ return 1;
+}
+#endif
+
/*
* Locate the user_struct for the passed UID. If found, take a ref on it. The
* caller must undo that ref with free_uid().