forked from luck/tmp_suning_uos_patched
6bfcb61789
[ Upstream commit 8f91efd870ea5d8bc10b0fcc9740db51cd4c0c83 ]
Race detected between psi_trigger_destroy/create as shown below, which
cause panic by accessing invalid psi_system->poll_wait->wait_queue_entry
and psi_system->poll_timer->entry->next. Under this modification, the
race window is removed by initialising poll_wait and poll_timer in
group_init which are executed only once at beginning.
psi_trigger_destroy() psi_trigger_create()
mutex_lock(trigger_lock);
rcu_assign_pointer(poll_task, NULL);
mutex_unlock(trigger_lock);
mutex_lock(trigger_lock);
if (!rcu_access_pointer(group->poll_task)) {
timer_setup(poll_timer, poll_timer_fn, 0);
rcu_assign_pointer(poll_task, task);
}
mutex_unlock(trigger_lock);
synchronize_rcu();
del_timer_sync(poll_timer); <-- poll_timer has been reinitialized by
psi_trigger_create()
So, trigger_lock/RCU correctly protects destruction of
group->poll_task but misses this race affecting poll_timer and
poll_wait.
Fixes:
|
||
|---|---|---|
| .. | ||
| autogroup.c | ||
| autogroup.h | ||
| clock.c | ||
| completion.c | ||
| core.c | ||
| cpuacct.c | ||
| cpudeadline.c | ||
| cpudeadline.h | ||
| cpufreq_schedutil.c | ||
| cpufreq.c | ||
| cpupri.c | ||
| cpupri.h | ||
| cputime.c | ||
| deadline.c | ||
| debug.c | ||
| fair.c | ||
| features.h | ||
| idle.c | ||
| isolation.c | ||
| loadavg.c | ||
| Makefile | ||
| membarrier.c | ||
| pelt.c | ||
| pelt.h | ||
| psi.c | ||
| rt.c | ||
| sched-pelt.h | ||
| sched.h | ||
| smp.h | ||
| stats.c | ||
| stats.h | ||
| stop_task.c | ||
| swait.c | ||
| topology.c | ||
| wait_bit.c | ||
| wait.c | ||