perf: Fix task refcount bugs (e7d0bc04) · Commits · e / devices / android_kernel_fairphone_FP4

Currently it looks like find_lively_task_by_vpid() takes a task ref and relies on find_get_context() to drop it. The problem is that perf_event_create_kernel_counter() shouldn't be dropping task refs. Signed-off-by:

Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by:

Frederic Weisbecker <fweisbec@gmail.com> Acked-by:

Matt Helsley <matthltc@us.ibm.com> LKML-Reference: <20101014203625.278436085@chello.nl> Signed-off-by:

Ingo Molnar <mingo@elte.hu>

kernel/perf_event.c

+4 −3

Original line number	Diff line number	Diff line
		@@ -2190,11 +2190,9 @@ find_get_context(struct pmu pmu, struct task_struct task, int cpu)
		}
		}

		put_task_struct(task);
		return ctx;

		errout:
		put_task_struct(task);
		return ERR_PTR(err);
		}

		@@ -5602,7 +5600,7 @@ SYSCALL_DEFINE5(perf_event_open,
		ctx = find_get_context(pmu, task, cpu);
		if (IS_ERR(ctx)) {
		err = PTR_ERR(ctx);
		goto err_group_fd;
		goto err_task;
		}

		/*
		@@ -5698,6 +5696,9 @@ SYSCALL_DEFINE5(perf_event_open,

		err_context:
		put_ctx(ctx);
		err_task:
		if (task)
		put_task_struct(task);
		err_group_fd:
		fput_light(group_file, fput_needed);
		free_event(event);