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 <[email protected]> --- kernel/perf_event.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- git/kernel/perf_event.c~1_find_get_context 2011-01-14 18:21:05.000000000 +0100 +++ git/kernel/perf_event.c 2011-01-18 16:56:40.000000000 +0100 @@ -2228,7 +2228,7 @@ 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); _______________________________________________ stable mailing list [email protected] http://linux.kernel.org/mailman/listinfo/stable
