From: Oleg Nesterov Date: Tue, 18 Jan 2011 16:10:32 +0000 (+0100) Subject: perf: Validate cpu early in perf_event_alloc() X-Git-Tag: v2.6.38-rc1~2^2 X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?p=pandora-kernel.git;a=commitdiff_plain;h=66832eb4baaaa9abe4c993ddf9113a79e39b9915 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 Acked-by: Peter Zijlstra Cc: Alan Stern Cc: Arnaldo Carvalho de Melo Cc: Frederic Weisbecker Cc: Paul Mackerras Cc: Prasad Cc: Roland McGrath Cc: gregkh@suse.de Cc: stable@kernel.org LKML-Reference: <20110118161032.GC693@redhat.com> Signed-off-by: Ingo Molnar --- diff --git a/kernel/perf_event.c b/kernel/perf_event.c index a962b1962eee..67d9bd70b746 100644 --- a/kernel/perf_event.c +++ b/kernel/perf_event.c @@ -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); @@ -5589,7 +5591,7 @@ perf_event_alloc(struct perf_event_attr *attr, int cpu, if (!overflow_handler && parent_event) overflow_handler = parent_event->overflow_handler; - + event->overflow_handler = overflow_handler; if (attr->disabled)