Commit 66832eb4 authored Jan 18, 2011 by Oleg Nesterov Committed by Ingo Molnar Jan 18, 2011

perf: Validate cpu early in perf_event_alloc()



Starting from perf_event_alloc()->perf_init_event(), the kernel
assumes that event->cpu is either -1 or the valid CPU number.

Change perf_event_alloc() to validate this argument early. This
also means we can remove the similar check in
find_get_context().

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Prasad <prasad@linux.vnet.ibm.com>
Cc: Roland McGrath <roland@redhat.com>
Cc: gregkh@suse.de
Cc: stable@kernel.org
LKML-Reference: <20110118161032.GC693@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

parent 22a4ec72

kernel/perf_event.c

+6 −4

Original line number	Diff line number	Diff line
		@@ -2233,9 +2233,6 @@ find_get_context(struct pmu pmu, struct task_struct task, int cpu)
		if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
		return ERR_PTR(-EACCES);

		if (cpu < 0 \|\| cpu >= nr_cpumask_bits)
		return ERR_PTR(-EINVAL);

		/*
		* We could be clever and allow to attach a event to an
		* offline CPU and activate it when the CPU comes up, but
		@@ -5541,6 +5538,11 @@ perf_event_alloc(struct perf_event_attr *attr, int cpu,
		struct hw_perf_event *hwc;
		long err;

		if ((unsigned)cpu >= nr_cpu_ids) {
		if (!task \|\| cpu != -1)
		return ERR_PTR(-EINVAL);
		}

		event = kzalloc(sizeof(*event), GFP_KERNEL);
		if (!event)
		return ERR_PTR(-ENOMEM);

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