This option enables additional debugging for detecting a grace period incompletion for synchronize_rcu() users. If a GP is not fully passed for any user, the warning message is emitted.
Signed-off-by: Uladzislau Rezki (Sony) <[email protected]> --- kernel/rcu/Kconfig.debug | 12 ++++++++++++ kernel/rcu/tree.c | 7 +++++-- 2 files changed, 17 insertions(+), 2 deletions(-) diff --git a/kernel/rcu/Kconfig.debug b/kernel/rcu/Kconfig.debug index 2984de629f74..3d44106ca1f0 100644 --- a/kernel/rcu/Kconfig.debug +++ b/kernel/rcu/Kconfig.debug @@ -143,4 +143,16 @@ config RCU_STRICT_GRACE_PERIOD when looking for certain types of RCU usage bugs, for example, too-short RCU read-side critical sections. +config RCU_SR_NORMAL_DEBUG_GP + bool "Debug synchronize_rcu() callers for a grace period completion" + depends on DEBUG_KERNEL && RCU_EXPERT + default n + help + This option enables additional debugging for detecting a grace + period incompletion for synchronize_rcu() users. If a GP is not + fully passed for any user, the warning message is emitted. + + Say Y here if you want to enable such debugging + Say N if you are unsure. + endmenu # "RCU Debugging" diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index c0d3e46730e8..421bce4b8dd7 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -1547,7 +1547,8 @@ static void rcu_sr_normal_complete(struct llist_node *node) (struct rcu_head *) node, struct rcu_synchronize, head); unsigned long oldstate = (unsigned long) rs->head.func; - WARN_ONCE(!rcu_gp_is_expedited() && !poll_state_synchronize_rcu(oldstate), + WARN_ONCE(IS_ENABLED(CONFIG_RCU_SR_NORMAL_DEBUG_GP) && + !poll_state_synchronize_rcu(oldstate), "A full grace period is not passed yet: %lu", rcu_seq_diff(get_state_synchronize_rcu(), oldstate)); @@ -3822,7 +3823,9 @@ static void synchronize_rcu_normal(void) * This code might be preempted, therefore take a GP * snapshot before adding a request. */ - rs.head.func = (void *) get_state_synchronize_rcu(); + if (IS_ENABLED(CONFIG_RCU_SR_NORMAL_DEBUG_GP)) + rs.head.func = (void *) get_state_synchronize_rcu(); + rcu_sr_normal_add_req(&rs); /* Kick a GP and start waiting. */ -- 2.39.2
