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authorMike Galbraith <efault@gmx.de>2012-10-28 12:19:23 -0700
committerIngo Molnar <mingo@kernel.org>2012-10-30 10:26:04 +0100
commit5258f386ea4e8454bc801fb443e8a4217da1947c (patch)
treec97487f040b95f83a2c9d31d51cbfe57f35e59e3 /fs/proc
parent8ed92e51f99c2199c64cb33b4ba95ab12940a94c (diff)
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 <efault@gmx.de> Cc: Xiaotian Feng <xtfeng@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Xiaotian Feng <dannyfeng@tencent.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: <stable@vger.kernel.org> # v3.6 Link: http://lkml.kernel.org/r/1351451963.4999.8.camel@maggy.simpson.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'fs/proc')
-rw-r--r--fs/proc/base.c78
1 files changed, 0 insertions, 78 deletions
diff --git a/fs/proc/base.c b/fs/proc/base.c
index 1b6c84cbdb7..bb1d9623bad 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)
{
@@ -3036,9 +2961,6 @@ static const struct pid_entry tgid_base_stuff[] = {
#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
INF("syscall", S_IRUGO, proc_pid_syscall),