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SubjectRe: [RFC][PATCH 1/7] perf: Fix task refcount issues
On Thu, Oct 14, 2010 at 10:34:05PM +0200, Peter Zijlstra wrote:
> 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>
> Cc: Frederic Weisbecker <fweisbec@gmail.com>
> Cc: Matt Helsley <matthltc@us.ibm.com>


Looks good.

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



> ---
> kernel/perf_event.c | 7 ++++---
> 1 file changed, 4 insertions(+), 3 deletions(-)
>
> Index: linux-2.6/kernel/perf_event.c
> ===================================================================
> --- linux-2.6.orig/kernel/perf_event.c
> +++ linux-2.6/kernel/perf_event.c
> @@ -2124,11 +2124,9 @@ find_get_context(struct pmu *pmu, struct
> }
> }
>
> - put_task_struct(task);
> return ctx;
>
> errout:
> - put_task_struct(task);
> return ERR_PTR(err);
> }
>
> @@ -5536,7 +5534,7 @@ 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;
> }
>
> /*
> @@ -5632,6 +5630,9 @@ 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);
>
>



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