Recently lockless_dereference() was added which can be used in place of
hard-coding smp_read_barrier_depends(). The following PATCH makes the change.
Signed-off-by: Pranith Kumar <bobby.pr...@gmail.com>
---
kernel/events/core.c | 3 +--
kernel/events/uprobes.c | 8 ++++----
2 files changed, 5 insertions(+), 6 deletions(-)
diff --git a/kernel/events/core.c b/kernel/events/core.c
index d59fdc0..9dd5920 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -3400,14 +3400,13 @@ static void perf_remove_from_owner(struct perf_event
*event)
struct task_struct *owner;
rcu_read_lock();
- owner = ACCESS_ONCE(event->owner);
/*
* Matches the smp_wmb() in perf_event_exit_task(). If we observe
* !owner it means the list deletion is complete and we can indeed
* free this event, otherwise we need to serialize on
* owner->perf_event_mutex.
*/
- smp_read_barrier_depends();
+ owner = lockless_dereference(event->owner);
if (owner) {
/*
* Since delayed_put_task_struct() also drops the last
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index 6158a64b..c070949 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -1212,8 +1212,8 @@ static struct xol_area *get_xol_area(void)
if (!mm->uprobes_state.xol_area)
__create_xol_area(0);
- area = mm->uprobes_state.xol_area;
- smp_read_barrier_depends(); /* pairs with wmb in xol_add_vma() */
+ /* pairs with wmb in xol_add_vma() */
+ area = lockless_dereference(mm->uprobes_state.xol_area);
return area;
}
@@ -1507,8 +1507,8 @@ static unsigned long get_trampoline_vaddr(void)
struct xol_area *area;
unsigned long trampoline_vaddr = -1;
- area = current->mm->uprobes_state.xol_area;
- smp_read_barrier_depends();
+ area = lockless_dereference(current->mm->uprobes_state.xol_area);
+
if (area)
trampoline_vaddr = area->vaddr;
--
1.9.1
--
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