| Date | Tue, 15 Feb 2011 16:14:22 -0800 | From | Greg KH <> | Subject | [205/272] perf: Find_get_context: fix the per-cpu-counter check |
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2.6.37-stable review patch. If anyone has any objections, please let us know.
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From: Oleg Nesterov <oleg@redhat.com>
commit 22a4ec729017ba613337a28f306f94ba5023fe2e upstream.
If task == NULL, find_get_context() should always check that cpu is correct.
Afaics, the bug was introduced by 38a81da2 "perf events: Clean up pid passing", but even before that commit "&& cpu != -1" was not exactly right, -ESRCH from find_task_by_vpid() is not accurate.
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> LKML-Reference: <20110118161008.GB693@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- kernel/perf_event.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/kernel/perf_event.c +++ b/kernel/perf_event.c @@ -2100,7 +2100,7 @@ find_get_context(struct pmu *pmu, struct unsigned long flags; int ctxn, err; - if (!task && cpu != -1) { + if (!task) { /* Must be root to operate on a CPU event: */ if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN)) return ERR_PTR(-EACCES);
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