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authorDave Airlie <airlied@redhat.com>2015-01-22 10:44:41 +1000
committerDave Airlie <airlied@redhat.com>2015-01-22 10:44:41 +1000
commit281d1bbd34b734e4f22b30b6f3b673dda46a7470 (patch)
treef67a2d45d248e9deaa1c68d3f8f33cdf476daacd /kernel/exit.c
parentbfa55bd4990815b055162b6d5d031f37a39942a5 (diff)
parentb942c653ae265abbd31032f3b4f5f857e5c7c723 (diff)
Merge remote-tracking branch 'origin/master' into drm-next
Backmerge Linus tree after rc5 + drm-fixes went in. There were a few amdkfd conflicts I wanted to avoid, and Ben requested this for nouveau also. Conflicts: drivers/gpu/drm/amd/amdkfd/Makefile drivers/gpu/drm/amd/amdkfd/kfd_chardev.c drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager.c drivers/gpu/drm/amd/amdkfd/kfd_priv.h drivers/gpu/drm/amd/include/kgd_kfd_interface.h drivers/gpu/drm/i915/intel_runtime_pm.c drivers/gpu/drm/radeon/radeon_kfd.c
Diffstat (limited to 'kernel/exit.c')
-rw-r--r--kernel/exit.c12
1 files changed, 9 insertions, 3 deletions
diff --git a/kernel/exit.c b/kernel/exit.c
index 1ea4369890a3..6806c55475ee 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -1287,9 +1287,15 @@ static int wait_task_continued(struct wait_opts *wo, struct task_struct *p)
static int wait_consider_task(struct wait_opts *wo, int ptrace,
struct task_struct *p)
{
+ /*
+ * We can race with wait_task_zombie() from another thread.
+ * Ensure that EXIT_ZOMBIE -> EXIT_DEAD/EXIT_TRACE transition
+ * can't confuse the checks below.
+ */
+ int exit_state = ACCESS_ONCE(p->exit_state);
int ret;
- if (unlikely(p->exit_state == EXIT_DEAD))
+ if (unlikely(exit_state == EXIT_DEAD))
return 0;
ret = eligible_child(wo, p);
@@ -1310,7 +1316,7 @@ static int wait_consider_task(struct wait_opts *wo, int ptrace,
return 0;
}
- if (unlikely(p->exit_state == EXIT_TRACE)) {
+ if (unlikely(exit_state == EXIT_TRACE)) {
/*
* ptrace == 0 means we are the natural parent. In this case
* we should clear notask_error, debugger will notify us.
@@ -1337,7 +1343,7 @@ static int wait_consider_task(struct wait_opts *wo, int ptrace,
}
/* slay zombie? */
- if (p->exit_state == EXIT_ZOMBIE) {
+ if (exit_state == EXIT_ZOMBIE) {
/* we don't reap group leaders with subthreads */
if (!delay_group_leader(p)) {
/*