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authorDavid S. Miller <davem@davemloft.net>2016-11-27 05:42:21 +0100
committerDavid S. Miller <davem@davemloft.net>2016-11-27 05:42:21 +0100
commit0b42f25d2f123bb7fbd3565d003a8ea9e1e810fe (patch)
tree77856ad061e97e86027df1fa6efdf20a9fe309b5 /kernel
parentMerge branch 'mlxsw-trap-groups-and-policers' (diff)
parentMerge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/vir... (diff)
downloadlinux-0b42f25d2f123bb7fbd3565d003a8ea9e1e810fe.tar.xz
linux-0b42f25d2f123bb7fbd3565d003a8ea9e1e810fe.zip
Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
udplite conflict is resolved by taking what 'net-next' did which removed the backlog receive method assignment, since it is no longer necessary. Two entries were added to the non-priv ethtool operations switch statement, one in 'net' and one in 'net-next, so simple overlapping changes. Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/events/core.c13
-rw-r--r--kernel/exit.c1
-rw-r--r--kernel/sched/auto_group.c36
3 files changed, 42 insertions, 8 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 0e292132efac..6ee1febdf6ff 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -902,6 +902,17 @@ list_update_cgroup_event(struct perf_event *event,
* this will always be called from the right CPU.
*/
cpuctx = __get_cpu_context(ctx);
+
+ /* Only set/clear cpuctx->cgrp if current task uses event->cgrp. */
+ if (perf_cgroup_from_task(current, ctx) != event->cgrp) {
+ /*
+ * We are removing the last cpu event in this context.
+ * If that event is not active in this cpu, cpuctx->cgrp
+ * should've been cleared by perf_cgroup_switch.
+ */
+ WARN_ON_ONCE(!add && cpuctx->cgrp);
+ return;
+ }
cpuctx->cgrp = add ? event->cgrp : NULL;
}
@@ -8018,6 +8029,7 @@ restart:
* if <size> is not specified, the range is treated as a single address.
*/
enum {
+ IF_ACT_NONE = -1,
IF_ACT_FILTER,
IF_ACT_START,
IF_ACT_STOP,
@@ -8041,6 +8053,7 @@ static const match_table_t if_tokens = {
{ IF_SRC_KERNEL, "%u/%u" },
{ IF_SRC_FILEADDR, "%u@%s" },
{ IF_SRC_KERNELADDR, "%u" },
+ { IF_ACT_NONE, NULL },
};
/*
diff --git a/kernel/exit.c b/kernel/exit.c
index 9d68c45ebbe3..3076f3089919 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -836,6 +836,7 @@ void __noreturn do_exit(long code)
*/
perf_event_exit_task(tsk);
+ sched_autogroup_exit_task(tsk);
cgroup_exit(tsk);
/*
diff --git a/kernel/sched/auto_group.c b/kernel/sched/auto_group.c
index a5d966cb8891..f1c8fd566246 100644
--- a/kernel/sched/auto_group.c
+++ b/kernel/sched/auto_group.c
@@ -111,10 +111,13 @@ bool task_wants_autogroup(struct task_struct *p, struct task_group *tg)
{
if (tg != &root_task_group)
return false;
-
/*
- * We can only assume the task group can't go away on us if
- * autogroup_move_group() can see us on ->thread_group list.
+ * If we race with autogroup_move_group() the caller can use the old
+ * value of signal->autogroup but in this case sched_move_task() will
+ * be called again before autogroup_kref_put().
+ *
+ * However, there is no way sched_autogroup_exit_task() could tell us
+ * to avoid autogroup->tg, so we abuse PF_EXITING flag for this case.
*/
if (p->flags & PF_EXITING)
return false;
@@ -122,6 +125,16 @@ bool task_wants_autogroup(struct task_struct *p, struct task_group *tg)
return true;
}
+void sched_autogroup_exit_task(struct task_struct *p)
+{
+ /*
+ * We are going to call exit_notify() and autogroup_move_group() can't
+ * see this thread after that: we can no longer use signal->autogroup.
+ * See the PF_EXITING check in task_wants_autogroup().
+ */
+ sched_move_task(p);
+}
+
static void
autogroup_move_group(struct task_struct *p, struct autogroup *ag)
{
@@ -138,13 +151,20 @@ autogroup_move_group(struct task_struct *p, struct autogroup *ag)
}
p->signal->autogroup = autogroup_kref_get(ag);
-
- if (!READ_ONCE(sysctl_sched_autogroup_enabled))
- goto out;
-
+ /*
+ * We can't avoid sched_move_task() after we changed signal->autogroup,
+ * this process can already run with task_group() == prev->tg or we can
+ * race with cgroup code which can read autogroup = prev under rq->lock.
+ * In the latter case for_each_thread() can not miss a migrating thread,
+ * cpu_cgroup_attach() must not be possible after cgroup_exit() and it
+ * can't be removed from thread list, we hold ->siglock.
+ *
+ * If an exiting thread was already removed from thread list we rely on
+ * sched_autogroup_exit_task().
+ */
for_each_thread(p, t)
sched_move_task(t);
-out:
+
unlock_task_sighand(p, &flags);
autogroup_kref_put(prev);
}