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@xxxxxxxxxxxxx/ Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: John Ogness <john.ogness@xxxxxxxxxxxxx> Cc: Petr Mladek <pmladek@xxxxxxxx> --- kernel/rcu/srcutree.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c index 09a11f2c2042..5772b8659c89 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; } -- 2.31.1.189.g2e36527f23
