From: Alexander Shishkin <[email protected]> When a child event is allocated in the inherit_event() path, the VMA based filter offsets are not copied from the parent, even though the address space mapping of the new task remains the same, which leads to no trace for the new task until exec.
Reported-by: Mansour Alharthi <[email protected]> Signed-off-by: Alexander Shishkin <[email protected]> Tested-by: Mathieu Poirier <[email protected]> Acked-by: Peter Zijlstra <[email protected]> Cc: Jiri Olsa <[email protected]> Fixes: 375637bc5249 ("perf/core: Introduce address range filtering") Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Arnaldo Carvalho de Melo <[email protected]> --- kernel/events/core.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/kernel/events/core.c b/kernel/events/core.c index 5aeb4c74fb99..2d89efc0a3e0 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -1255,6 +1255,7 @@ static void put_ctx(struct perf_event_context *ctx) * perf_event_context::lock * perf_event::mmap_mutex * mmap_sem + * perf_addr_filters_head::lock * * cpu_hotplug_lock * pmus_lock @@ -10312,6 +10313,20 @@ perf_event_alloc(struct perf_event_attr *attr, int cpu, goto err_per_task; } + /* + * Clone the parent's vma offsets: they are valid until exec() + * even if the mm is not shared with the parent. + */ + if (event->parent) { + struct perf_addr_filters_head *ifh = perf_event_addr_filters(event); + + raw_spin_lock_irq(&ifh->lock); + memcpy(event->addr_filters_offs, + event->parent->addr_filters_offs, + pmu->nr_addr_filters * sizeof(unsigned long)); + raw_spin_unlock_irq(&ifh->lock); + } + /* force hw sync on the address filters */ event->addr_filters_gen = 1; } -- 2.20.1
