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[1/7] rcu/exp: Fix RCU expedited parallel grace period kworker allocation failure recovery

Message ID 20240112154621.261852-2-frederic@kernel.org (mailing list archive)
State Accepted
Commit 46ea64d21b96a017681f24779b8d3b7fb36cde65
Headers show
Series rcu: Fix expedited GP deadlock | expand

Commit Message

Frederic Weisbecker Jan. 12, 2024, 3:46 p.m. UTC 
Under CONFIG_RCU_EXP_KTHREAD=y, the nodes initialization for expedited
grace periods is queued to a kworker. However if the allocation of that
kworker failed, the nodes initialization is performed synchronously by
the caller instead.

Now the check for kworker initialization failure relies on the kworker
pointer to be NULL while its value might actually encapsulate an
allocation failure error.

Make sure to handle this case.

Reviewed-by: Kalesh Singh <kaleshsingh@google.com>
Fixes: 9621fbee44df ("rcu: Move expedited grace period (GP) work to RT kthread_worker")
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
---
 kernel/rcu/tree.c | 1 +
 1 file changed, 1 insertion(+)
diff mbox series

Patch

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 499803234176..b000c1a83fc2 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -4760,6 +4760,7 @@  static void __init rcu_start_exp_gp_kworkers(void)
 	rcu_exp_par_gp_kworker = kthread_create_worker(0, par_gp_kworker_name);
 	if (IS_ERR_OR_NULL(rcu_exp_par_gp_kworker)) {
 		pr_err("Failed to create %s!\n", par_gp_kworker_name);
+		rcu_exp_par_gp_kworker = NULL;
 		kthread_destroy_worker(rcu_exp_gp_kworker);
 		return;
 	}