From: Alexander Shishkin alexander.shishkin@linux.intel.com
[ Upstream commit 18736eef12137c59f60cc9f56dc5bea05c92e0eb ]
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 malharthi9@gatech.edu Signed-off-by: Alexander Shishkin alexander.shishkin@linux.intel.com Tested-by: Mathieu Poirier mathieu.poirier@linaro.org Acked-by: Peter Zijlstra peterz@infradead.org Cc: Jiri Olsa jolsa@redhat.com Fixes: 375637bc5249 ("perf/core: Introduce address range filtering") Link: http://lkml.kernel.org/r/20190215115655.63469-2-alexander.shishkin@linux.int... Signed-off-by: Arnaldo Carvalho de Melo acme@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- kernel/events/core.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+)
diff --git a/kernel/events/core.c b/kernel/events/core.c index 460d5fd3ec4e4..9a5559f5938a5 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -1254,6 +1254,7 @@ 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 @@ -10136,6 +10137,20 @@ 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; }