diff options
| author | Paul E. McKenney <paulmck@kernel.org> | 2022-04-08 09:21:50 -0700 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@kernel.org> | 2022-04-11 17:06:43 -0700 |
| commit | ab2756ea6b74987849b44ad0e33c3cfec159033b (patch) | |
| tree | 166ae0bb6674eb0ea22272bdc591e36d5f8470fe /kernel/rcu | |
| parent | 07d95c34e8125a7bf833a94bc3c9d51992d92c45 (diff) | |
rcu-tasks: Handle sparse cpu_possible_mask in rcu_tasks_invoke_cbs()
If the cpu_possible_mask is sparse (for example, if bits are set only for
CPUs 0, 4, 8, ...), then rcu_tasks_invoke_cbs() will access per-CPU data
for a CPU not in cpu_possible_mask. It makes these accesses while doing
a workqueue-based binary search for non-empty callback lists. Although
this search must pass through CPUs not represented in cpu_possible_mask,
it has no need to check the callback list for such CPUs.
This commit therefore changes the rcu_tasks_invoke_cbs() function's
binary search so as to only check callback lists for CPUs present in
cpu_possible_mask.
Reported-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Diffstat (limited to 'kernel/rcu')
| -rw-r--r-- | kernel/rcu/tasks.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h index fd70d86eb7cd..3925e32159b5 100644 --- a/kernel/rcu/tasks.h +++ b/kernel/rcu/tasks.h @@ -468,7 +468,7 @@ static void rcu_tasks_invoke_cbs(struct rcu_tasks *rtp, struct rcu_tasks_percpu } } - if (rcu_segcblist_empty(&rtpcp->cblist)) + if (rcu_segcblist_empty(&rtpcp->cblist) || !cpu_possible(cpu)) return; raw_spin_lock_irqsave_rcu_node(rtpcp, flags); rcu_segcblist_advance(&rtpcp->cblist, rcu_seq_current(&rtp->tasks_gp_seq)); |