From 5258f386ea4e8454bc801fb443e8a4217da1947c Mon Sep 17 00:00:00 2001 From: Mike Galbraith Date: Sun, 28 Oct 2012 12:19:23 -0700 Subject: sched/autogroup: Fix crash on reboot when autogroup is disabled Due to these two commits: 8323f26ce342 sched: Fix race in task_group() 800d4d30c8f2 sched, autogroup: Stop going ahead if autogroup is disabled ... autogroup scheduling's dynamic knobs are wrecked. With both patches applied, all you have to do to crash a box is disable autogroup during boot up, then reboot.. boom, NULL pointer dereference due to 800d4d30 not allowing autogroup to move things, and 8323f26ce making that the only way to switch runqueues. Remove most of the (dysfunctional) knobs and turn the remaining sched_autogroup_enabled knob readonly. If the user fiddles with cgroups hereafter, once tasks are moved, autogroup won't mess with them again unless they call setsid(). No knobs, no glitz, nada, just a cute little thing folks can turn on if they don't want to muck about with cgroups and/or systemd. Signed-off-by: Mike Galbraith Cc: Xiaotian Feng Cc: Peter Zijlstra Cc: Xiaotian Feng Cc: Linus Torvalds Cc: Andrew Morton Cc: Oleg Nesterov Cc: # v3.6 Link: http://lkml.kernel.org/r/1351451963.4999.8.camel@maggy.simpson.net Signed-off-by: Ingo Molnar --- fs/proc/base.c | 78 ---------------------------------------------------------- 1 file changed, 78 deletions(-) (limited to 'fs/proc') diff --git a/fs/proc/base.c b/fs/proc/base.c index 1b6c84cbdb73..bb1d9623bad2 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -1271,81 +1271,6 @@ static const struct file_operations proc_pid_sched_operations = { #endif -#ifdef CONFIG_SCHED_AUTOGROUP -/* - * Print out autogroup related information: - */ -static int sched_autogroup_show(struct seq_file *m, void *v) -{ - struct inode *inode = m->private; - struct task_struct *p; - - p = get_proc_task(inode); - if (!p) - return -ESRCH; - proc_sched_autogroup_show_task(p, m); - - put_task_struct(p); - - return 0; -} - -static ssize_t -sched_autogroup_write(struct file *file, const char __user *buf, - size_t count, loff_t *offset) -{ - struct inode *inode = file->f_path.dentry->d_inode; - struct task_struct *p; - char buffer[PROC_NUMBUF]; - int nice; - int err; - - memset(buffer, 0, sizeof(buffer)); - if (count > sizeof(buffer) - 1) - count = sizeof(buffer) - 1; - if (copy_from_user(buffer, buf, count)) - return -EFAULT; - - err = kstrtoint(strstrip(buffer), 0, &nice); - if (err < 0) - return err; - - p = get_proc_task(inode); - if (!p) - return -ESRCH; - - err = proc_sched_autogroup_set_nice(p, nice); - if (err) - count = err; - - put_task_struct(p); - - return count; -} - -static int sched_autogroup_open(struct inode *inode, struct file *filp) -{ - int ret; - - ret = single_open(filp, sched_autogroup_show, NULL); - if (!ret) { - struct seq_file *m = filp->private_data; - - m->private = inode; - } - return ret; -} - -static const struct file_operations proc_pid_sched_autogroup_operations = { - .open = sched_autogroup_open, - .read = seq_read, - .write = sched_autogroup_write, - .llseek = seq_lseek, - .release = single_release, -}; - -#endif /* CONFIG_SCHED_AUTOGROUP */ - static ssize_t comm_write(struct file *file, const char __user *buf, size_t count, loff_t *offset) { @@ -3035,9 +2960,6 @@ static const struct pid_entry tgid_base_stuff[] = { INF("limits", S_IRUGO, proc_pid_limits), #ifdef CONFIG_SCHED_DEBUG REG("sched", S_IRUGO|S_IWUSR, proc_pid_sched_operations), -#endif -#ifdef CONFIG_SCHED_AUTOGROUP - REG("autogroup", S_IRUGO|S_IWUSR, proc_pid_sched_autogroup_operations), #endif REG("comm", S_IRUGO|S_IWUSR, proc_pid_set_comm_operations), #ifdef CONFIG_HAVE_ARCH_TRACEHOOK -- cgit v1.2.3-73-gaa49b From e80d0a1ae8bb8fee0edd37427836f108b30f596b Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Wed, 21 Nov 2012 16:26:44 +0100 Subject: cputime: Rename thread_group_times to thread_group_cputime_adjusted We have thread_group_cputime() and thread_group_times(). The naming doesn't provide enough information about the difference between these two APIs. To lower the confusion, rename thread_group_times() to thread_group_cputime_adjusted(). This name better suggests that it's a version of thread_group_cputime() that does some stabilization on the raw cputime values. ie here: scale on top of CFS runtime stats and bound lower value for monotonicity. Signed-off-by: Frederic Weisbecker Cc: Ingo Molnar Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Steven Rostedt Cc: Paul Gortmaker --- fs/proc/array.c | 4 ++-- include/linux/sched.h | 4 ++-- kernel/exit.c | 4 ++-- kernel/sched/cputime.c | 8 ++++---- kernel/sys.c | 6 +++--- 5 files changed, 13 insertions(+), 13 deletions(-) (limited to 'fs/proc') diff --git a/fs/proc/array.c b/fs/proc/array.c index c1c207c36cae..d3696708fc1a 100644 --- a/fs/proc/array.c +++ b/fs/proc/array.c @@ -438,7 +438,7 @@ static int do_task_stat(struct seq_file *m, struct pid_namespace *ns, min_flt += sig->min_flt; maj_flt += sig->maj_flt; - thread_group_times(task, &utime, &stime); + thread_group_cputime_adjusted(task, &utime, &stime); gtime += sig->gtime; } @@ -454,7 +454,7 @@ static int do_task_stat(struct seq_file *m, struct pid_namespace *ns, if (!whole) { min_flt = task->min_flt; maj_flt = task->maj_flt; - task_times(task, &utime, &stime); + task_cputime_adjusted(task, &utime, &stime); gtime = task->gtime; } diff --git a/include/linux/sched.h b/include/linux/sched.h index e1581a029e3d..e75cab5820ab 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1751,8 +1751,8 @@ static inline void put_task_struct(struct task_struct *t) __put_task_struct(t); } -extern void task_times(struct task_struct *p, cputime_t *ut, cputime_t *st); -extern void thread_group_times(struct task_struct *p, cputime_t *ut, cputime_t *st); +extern void task_cputime_adjusted(struct task_struct *p, cputime_t *ut, cputime_t *st); +extern void thread_group_cputime_adjusted(struct task_struct *p, cputime_t *ut, cputime_t *st); /* * Per process flags diff --git a/kernel/exit.c b/kernel/exit.c index 346616c0092c..618f7ee56003 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -1186,11 +1186,11 @@ static int wait_task_zombie(struct wait_opts *wo, struct task_struct *p) * as other threads in the parent group can be right * here reaping other children at the same time. * - * We use thread_group_times() to get times for the thread + * We use thread_group_cputime_adjusted() to get times for the thread * group, which consolidates times for all threads in the * group including the group leader. */ - thread_group_times(p, &tgutime, &tgstime); + thread_group_cputime_adjusted(p, &tgutime, &tgstime); spin_lock_irq(&p->real_parent->sighand->siglock); psig = p->real_parent->signal; sig = p->signal; diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c index e56f138a23c7..7dc155371b95 100644 --- a/kernel/sched/cputime.c +++ b/kernel/sched/cputime.c @@ -445,13 +445,13 @@ void account_idle_ticks(unsigned long ticks) * Use precise platform statistics if available: */ #ifdef CONFIG_VIRT_CPU_ACCOUNTING -void task_times(struct task_struct *p, cputime_t *ut, cputime_t *st) +void task_cputime_adjusted(struct task_struct *p, cputime_t *ut, cputime_t *st) { *ut = p->utime; *st = p->stime; } -void thread_group_times(struct task_struct *p, cputime_t *ut, cputime_t *st) +void thread_group_cputime_adjusted(struct task_struct *p, cputime_t *ut, cputime_t *st) { struct task_cputime cputime; @@ -516,7 +516,7 @@ static cputime_t scale_utime(cputime_t utime, cputime_t rtime, cputime_t total) return (__force cputime_t) temp; } -void task_times(struct task_struct *p, cputime_t *ut, cputime_t *st) +void task_cputime_adjusted(struct task_struct *p, cputime_t *ut, cputime_t *st) { cputime_t rtime, utime = p->utime, total = utime + p->stime; @@ -543,7 +543,7 @@ void task_times(struct task_struct *p, cputime_t *ut, cputime_t *st) /* * Must be called with siglock held. */ -void thread_group_times(struct task_struct *p, cputime_t *ut, cputime_t *st) +void thread_group_cputime_adjusted(struct task_struct *p, cputime_t *ut, cputime_t *st) { struct signal_struct *sig = p->signal; struct task_cputime cputime; diff --git a/kernel/sys.c b/kernel/sys.c index e6e0ece5f6a0..265b37690421 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -1046,7 +1046,7 @@ void do_sys_times(struct tms *tms) cputime_t tgutime, tgstime, cutime, cstime; spin_lock_irq(¤t->sighand->siglock); - thread_group_times(current, &tgutime, &tgstime); + thread_group_cputime_adjusted(current, &tgutime, &tgstime); cutime = current->signal->cutime; cstime = current->signal->cstime; spin_unlock_irq(¤t->sighand->siglock); @@ -1704,7 +1704,7 @@ static void k_getrusage(struct task_struct *p, int who, struct rusage *r) utime = stime = 0; if (who == RUSAGE_THREAD) { - task_times(current, &utime, &stime); + task_cputime_adjusted(current, &utime, &stime); accumulate_thread_rusage(p, r); maxrss = p->signal->maxrss; goto out; @@ -1730,7 +1730,7 @@ static void k_getrusage(struct task_struct *p, int who, struct rusage *r) break; case RUSAGE_SELF: - thread_group_times(p, &tgutime, &tgstime); + thread_group_cputime_adjusted(p, &tgutime, &tgstime); utime += tgutime; stime += tgstime; r->ru_nvcsw += p->signal->nvcsw; -- cgit v1.2.3-73-gaa49b