diff options
| author | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2017-10-05 15:03:10 -0700 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2017-11-28 15:51:20 -0800 |
| commit | 2342172fd6c148506456862d795c7f155baf6797 (patch) | |
| tree | cd9d468341bd806b71b7d4c7c80ceab84e87ed56 /kernel | |
| parent | 914955e18ca09fc404d7fc3614bb04c96a03692c (diff) | |
| download | blackbird-obmc-linux-2342172fd6c148506456862d795c7f155baf6797.tar.gz blackbird-obmc-linux-2342172fd6c148506456862d795c7f155baf6797.zip | |
rcu: Avoid ->dynticks_nesting store tearing
Although ->dynticks_nesting is updated only by process level, it is
accessed from hardirq to check for interrupt-from-idle quiescent states.
Store tearing is thus possible, so this commit applies WRITE_ONCE()
to ->dynticks_nesting stores.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/rcu/tree.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 80cada11f544..b2ded4d436c6 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -778,7 +778,7 @@ static void rcu_eqs_enter_common(bool user) do_nocb_deferred_wakeup(rdp); } rcu_prepare_for_idle(); - rdtp->dynticks_nesting = 0; + WRITE_ONCE(rdtp->dynticks_nesting, 0); /* Avoid irq-access tearing. */ rcu_dynticks_eqs_enter(); rcu_dynticks_task_enter(); } @@ -976,7 +976,7 @@ static void rcu_eqs_exit(bool user) rdtp->dynticks_nesting++; } else { rcu_eqs_exit_common(1, user); - rdtp->dynticks_nesting = 1; + WRITE_ONCE(rdtp->dynticks_nesting, 1); WRITE_ONCE(rdtp->dynticks_nmi_nesting, DYNTICK_IRQ_NONIDLE); } } @@ -3713,7 +3713,7 @@ rcu_init_percpu_data(int cpu, struct rcu_state *rsp) if (rcu_segcblist_empty(&rdp->cblist) && /* No early-boot CBs? */ !init_nocb_callback_list(rdp)) rcu_segcblist_init(&rdp->cblist); /* Re-enable callbacks. */ - rdp->dynticks->dynticks_nesting = 1; + rdp->dynticks->dynticks_nesting = 1; /* CPU not up, no tearing. */ rcu_dynticks_eqs_online(); raw_spin_unlock_rcu_node(rnp); /* irqs remain disabled. */ |
