Messages in this thread Patch in this message | | | From | Andrea Parri <> | Subject | [PATCH] events/uprobes: move smp_read_barrier_depends() where needed | Date | Thu, 9 Jun 2016 20:18:41 +0200 |
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There is no need to use the barrier if there is no dereference/ memory access; move it where needed (currently, affecting only Alpha). While touching this, also make the reads _ONCE().
Signed-off-by: Andrea Parri <parri.andrea@gmail.com> --- kernel/events/uprobes.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index b7a525ab2083..b1364acd683e 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -1520,10 +1520,11 @@ 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(); - if (area) - trampoline_vaddr = area->vaddr; + area = READ_ONCE(current->mm->uprobes_state.xol_area); + if (area) { + smp_read_barrier_depends(); + trampoline_vaddr = READ_ONCE(area->vaddr); + } return trampoline_vaddr; } -- 1.9.1
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