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authorPaul E. McKenney <paulmck@kernel.org>2022-09-20 14:54:41 -0700
committerPaul E. McKenney <paulmck@kernel.org>2022-10-20 15:02:27 -0700
commit36f65f1d1553e35cd9e6b281271f40d639a128c3 (patch)
tree91ad8b870888afc8299876118c7f1a60ff60a6ad /kernel/rcu
parent27120e7d2c4d5c438b76f9c6330037a52ad0722e (diff)
srcu: Check for consistent global per-srcu_struct NMI safety
This commit adds runtime checks to verify that a given srcu_struct uses consistent NMI-safe (or not) read-side primitives globally, but based on the per-CPU data. These global checks are made by the grace-period code that must scan the srcu_data structures anyway, and are done only in kernels built with CONFIG_PROVE_RCU=y. Link: https://lore.kernel.org/all/20220910221947.171557773@linutronix.de/ Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Reviewed-by: Frederic Weisbecker <frederic@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: John Ogness <john.ogness@linutronix.de> Cc: Petr Mladek <pmladek@suse.com>
Diffstat (limited to 'kernel/rcu')
-rw-r--r--kernel/rcu/srcutree.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c
index 30575864fcfa..87ae6f5c1eda 100644
--- a/kernel/rcu/srcutree.c
+++ b/kernel/rcu/srcutree.c
@@ -429,13 +429,18 @@ static unsigned long srcu_readers_lock_idx(struct srcu_struct *ssp, int idx)
static unsigned long srcu_readers_unlock_idx(struct srcu_struct *ssp, int idx)
{
int cpu;
+ unsigned long mask = 0;
unsigned long sum = 0;
for_each_possible_cpu(cpu) {
struct srcu_data *cpuc = per_cpu_ptr(ssp->sda, cpu);
sum += atomic_long_read(&cpuc->srcu_unlock_count[idx]);
+ if (IS_ENABLED(CONFIG_PROVE_RCU))
+ mask = mask | READ_ONCE(cpuc->srcu_nmi_safety);
}
+ WARN_ONCE(IS_ENABLED(CONFIG_PROVE_RCU) && (mask & (mask >> 1)),
+ "Mixed NMI-safe readers for srcu_struct at %ps.\n", ssp);
return sum;
}