Commit 547690a5 authored Feb 15, 2019 by Alexander Shishkin Committed by Yabin Cui Nov 06, 2019

UPSTREAM: perf: Copy parent's address filter offsets on clone



(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: 375637bc ("perf/core: Introduce address range filtering")
Link: http://lkml.kernel.org/r/20190215115655.63469-2-alexander.shishkin@linux.intel.com


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Bug: 140266694
Change-Id: I14af7095b0712ee6fc427eafc3d3486f0fc1b07c
Signed-off-by: Yabin Cui <yabinc@google.com>

parent 93b40c1d

kernel/events/core.c

+15 −0

Original line number	Diff line number	Diff line
		@@ -1259,6 +1259,7 @@ 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
		@@ -10141,6 +10142,20 @@ 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;
		}