diff options
| author | Zqiang <qiang.zhang1211@gmail.com> | 2025-05-07 19:26:05 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-08-20 18:30:33 +0200 |
| commit | cce3d027227c69e85896af9fbc6fa9af5c68f067 (patch) | |
| tree | 9b938d6446995a348ce1174d3dcf508275aa203a | |
| parent | 347b94ee253e7268ec4079d5fafba8f29981f7e7 (diff) | |
rcu/nocb: Fix possible invalid rdp's->nocb_cb_kthread pointer access
[ Upstream commit 1bba3900ca18bdae28d1b9fa10f16a8f8cb2ada1 ]
In the preparation stage of CPU online, if the corresponding
the rdp's->nocb_cb_kthread does not exist, will be created,
there is a situation where the rdp's rcuop kthreads creation fails,
and then de-offload this CPU's rdp, does not assign this CPU's
rdp->nocb_cb_kthread pointer, but this rdp's->nocb_gp_rdp and
rdp's->rdp_gp->nocb_gp_kthread is still valid.
This will cause the subsequent re-offload operation of this offline
CPU, which will pass the conditional check and the kthread_unpark()
will access invalid rdp's->nocb_cb_kthread pointer.
This commit therefore use rdp's->nocb_gp_kthread instead of
rdp_gp's->nocb_gp_kthread for safety check.
Signed-off-by: Zqiang <qiang.zhang1211@gmail.com>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Neeraj Upadhyay (AMD) <neeraj.upadhyay@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | kernel/rcu/tree_nocb.h | 5 |
1 files changed, 2 insertions, 3 deletions
diff --git a/kernel/rcu/tree_nocb.h b/kernel/rcu/tree_nocb.h index 2ad3a88623a7..a1a5942d7017 100644 --- a/kernel/rcu/tree_nocb.h +++ b/kernel/rcu/tree_nocb.h @@ -1152,7 +1152,6 @@ static bool rcu_nocb_rdp_offload_wait_cond(struct rcu_data *rdp) static int rcu_nocb_rdp_offload(struct rcu_data *rdp) { int wake_gp; - struct rcu_data *rdp_gp = rdp->nocb_gp_rdp; WARN_ON_ONCE(cpu_online(rdp->cpu)); /* @@ -1162,7 +1161,7 @@ static int rcu_nocb_rdp_offload(struct rcu_data *rdp) if (!rdp->nocb_gp_rdp) return -EINVAL; - if (WARN_ON_ONCE(!rdp_gp->nocb_gp_kthread)) + if (WARN_ON_ONCE(!rdp->nocb_gp_kthread)) return -EINVAL; pr_info("Offloading %d\n", rdp->cpu); @@ -1172,7 +1171,7 @@ static int rcu_nocb_rdp_offload(struct rcu_data *rdp) wake_gp = rcu_nocb_queue_toggle_rdp(rdp); if (wake_gp) - wake_up_process(rdp_gp->nocb_gp_kthread); + wake_up_process(rdp->nocb_gp_kthread); swait_event_exclusive(rdp->nocb_state_wq, rcu_nocb_rdp_offload_wait_cond(rdp)); |