aboutsummaryrefslogtreecommitdiffstats
path: root/include/linux
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2019-09-28 12:39:07 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2019-09-28 12:39:07 -0700
commit9c5efe9ae7df78600c0ee7bcce27516eb687fa6e (patch)
tree158cfb9720d876e68a14a4cccaffeb58fb7baac5 /include/linux
parentaefcf2f4b58155d27340ba5f9ddbe9513da8286d (diff)
parent4892f51ad54ddff2883a60b6ad4323c1f632a9d6 (diff)
Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler fixes from Ingo Molnar: - Apply a number of membarrier related fixes and cleanups, which fixes a use-after-free race in the membarrier code - Introduce proper RCU protection for tasks on the runqueue - to get rid of the subtle task_rcu_dereference() interface that was easy to get wrong - Misc fixes, but also an EAS speedup * 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched/fair: Avoid redundant EAS calculation sched/core: Remove double update_max_interval() call on CPU startup sched/core: Fix preempt_schedule() interrupt return comment sched/fair: Fix -Wunused-but-set-variable warnings sched/core: Fix migration to invalid CPU in __set_cpus_allowed_ptr() sched/membarrier: Return -ENOMEM to userspace on memory allocation failure sched/membarrier: Skip IPIs when mm->mm_users == 1 selftests, sched/membarrier: Add multi-threaded test sched/membarrier: Fix p->mm->membarrier_state racy load sched/membarrier: Call sync_core only before usermode for same mm sched/membarrier: Remove redundant check sched/membarrier: Fix private expedited registration check tasks, sched/core: RCUify the assignment of rq->curr tasks, sched/core: With a grace period after finish_task_switch(), remove unnecessary code tasks, sched/core: Ensure tasks are available for a grace period after leaving the runqueue tasks: Add a count of task RCU users sched/core: Convert vcpu_is_preempted() from macro to an inline function sched/fair: Remove unused cfs_rq_clock_task() function
Diffstat (limited to 'include/linux')
-rw-r--r--include/linux/mm_types.h14
-rw-r--r--include/linux/rcuwait.h20
-rw-r--r--include/linux/sched.h10
-rw-r--r--include/linux/sched/mm.h10
-rw-r--r--include/linux/sched/task.h2
5 files changed, 29 insertions, 27 deletions
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 5183e0d77dfa..2222fa795284 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -383,6 +383,16 @@ struct mm_struct {
unsigned long highest_vm_end; /* highest vma end address */
pgd_t * pgd;
+#ifdef CONFIG_MEMBARRIER
+ /**
+ * @membarrier_state: Flags controlling membarrier behavior.
+ *
+ * This field is close to @pgd to hopefully fit in the same
+ * cache-line, which needs to be touched by switch_mm().
+ */
+ atomic_t membarrier_state;
+#endif
+
/**
* @mm_users: The number of users including userspace.
*
@@ -452,9 +462,7 @@ struct mm_struct {
unsigned long flags; /* Must use atomic bitops to access */
struct core_state *core_state; /* coredumping support */
-#ifdef CONFIG_MEMBARRIER
- atomic_t membarrier_state;
-#endif
+
#ifdef CONFIG_AIO
spinlock_t ioctx_lock;
struct kioctx_table __rcu *ioctx_table;
diff --git a/include/linux/rcuwait.h b/include/linux/rcuwait.h
index 563290fc194f..75c97e4bbc57 100644
--- a/include/linux/rcuwait.h
+++ b/include/linux/rcuwait.h
@@ -6,16 +6,11 @@
/*
* rcuwait provides a way of blocking and waking up a single
- * task in an rcu-safe manner; where it is forbidden to use
- * after exit_notify(). task_struct is not properly rcu protected,
- * unless dealing with rcu-aware lists, ie: find_task_by_*().
+ * task in an rcu-safe manner.
*
- * Alternatively we have task_rcu_dereference(), but the return
- * semantics have different implications which would break the
- * wakeup side. The only time @task is non-nil is when a user is
- * blocked (or checking if it needs to) on a condition, and reset
- * as soon as we know that the condition has succeeded and are
- * awoken.
+ * The only time @task is non-nil is when a user is blocked (or
+ * checking if it needs to) on a condition, and reset as soon as we
+ * know that the condition has succeeded and are awoken.
*/
struct rcuwait {
struct task_struct __rcu *task;
@@ -37,13 +32,6 @@ extern void rcuwait_wake_up(struct rcuwait *w);
*/
#define rcuwait_wait_event(w, condition) \
({ \
- /* \
- * Complain if we are called after do_exit()/exit_notify(), \
- * as we cannot rely on the rcu critical region for the \
- * wakeup side. \
- */ \
- WARN_ON(current->exit_state); \
- \
rcu_assign_pointer((w)->task, current); \
for (;;) { \
/* \
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 70db597d6fd4..2c2e56bd8913 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1130,7 +1130,10 @@ struct task_struct {
struct tlbflush_unmap_batch tlb_ubc;
- struct rcu_head rcu;
+ union {
+ refcount_t rcu_users;
+ struct rcu_head rcu;
+ };
/* Cache last used pipe for splice(): */
struct pipe_inode_info *splice_pipe;
@@ -1839,7 +1842,10 @@ static inline void set_task_cpu(struct task_struct *p, unsigned int cpu)
* running or not.
*/
#ifndef vcpu_is_preempted
-# define vcpu_is_preempted(cpu) false
+static inline bool vcpu_is_preempted(int cpu)
+{
+ return false;
+}
#endif
extern long sched_setaffinity(pid_t pid, const struct cpumask *new_mask);
diff --git a/include/linux/sched/mm.h b/include/linux/sched/mm.h
index 4a7944078cc3..e6770012db18 100644
--- a/include/linux/sched/mm.h
+++ b/include/linux/sched/mm.h
@@ -362,16 +362,16 @@ enum {
static inline void membarrier_mm_sync_core_before_usermode(struct mm_struct *mm)
{
+ if (current->mm != mm)
+ return;
if (likely(!(atomic_read(&mm->membarrier_state) &
MEMBARRIER_STATE_PRIVATE_EXPEDITED_SYNC_CORE)))
return;
sync_core_before_usermode();
}
-static inline void membarrier_execve(struct task_struct *t)
-{
- atomic_set(&t->mm->membarrier_state, 0);
-}
+extern void membarrier_exec_mmap(struct mm_struct *mm);
+
#else
#ifdef CONFIG_ARCH_HAS_MEMBARRIER_CALLBACKS
static inline void membarrier_arch_switch_mm(struct mm_struct *prev,
@@ -380,7 +380,7 @@ static inline void membarrier_arch_switch_mm(struct mm_struct *prev,
{
}
#endif
-static inline void membarrier_execve(struct task_struct *t)
+static inline void membarrier_exec_mmap(struct mm_struct *mm)
{
}
static inline void membarrier_mm_sync_core_before_usermode(struct mm_struct *mm)
diff --git a/include/linux/sched/task.h b/include/linux/sched/task.h
index 3d90ed8f75f0..4b1c3b664f51 100644
--- a/include/linux/sched/task.h
+++ b/include/linux/sched/task.h
@@ -119,7 +119,7 @@ static inline void put_task_struct(struct task_struct *t)
__put_task_struct(t);
}
-struct task_struct *task_rcu_dereference(struct task_struct **ptask);
+void put_task_struct_rcu_user(struct task_struct *task);
#ifdef CONFIG_ARCH_WANTS_DYNAMIC_TASK_STRUCT
extern int arch_task_struct_size __read_mostly;

Privacy Policy