From: Iulia Manda Date: Mon, 17 Mar 2014 13:21:21 +0000 (+0200) Subject: torture: Notice if an all-zero cpumask is passed inside a critical section X-Git-Tag: next-20140516~31^2~11^3~13 X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=5ed63b199c5b58ed150ce50f1ea68de54669b13f;p=karo-tx-linux.git torture: Notice if an all-zero cpumask is passed inside a critical section In torture_shuffle_tasks function, the check if an all-zero mask can be passed to set_cpus_allowed_ptr() is redundant after clearing the shuffle_idle_cpu bit. If the mask had more than one bit set, after clearing a bit it has at least one bit set. If the mask had only one bit set, a check is made at the beginning, where the function returns, as there is no need to shuffle only one cpu. Also, this code is executed inside a critical section, delimited by get_online_cpus(), and put_online_cpus(), preventing CPUs from leaving between the check of num_online_cpus and the calls to set_cpus_allowed_ptr() function. Signed-off-by: Iulia Manda Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett --- diff --git a/kernel/torture.c b/kernel/torture.c index bc0ee382b3c8..ae1723a4c751 100644 --- a/kernel/torture.c +++ b/kernel/torture.c @@ -335,13 +335,8 @@ static void torture_shuffle_tasks(void) shuffle_idle_cpu = cpumask_next(shuffle_idle_cpu, shuffle_tmp_mask); if (shuffle_idle_cpu >= nr_cpu_ids) shuffle_idle_cpu = -1; - if (shuffle_idle_cpu != -1) { + else cpumask_clear_cpu(shuffle_idle_cpu, shuffle_tmp_mask); - if (cpumask_empty(shuffle_tmp_mask)) { - put_online_cpus(); - return; - } - } mutex_lock(&shuffle_task_mutex); list_for_each_entry(stp, &shuffle_task_list, st_l)