From: Kunwu Chan <kunwu.chan@gmail.com>
To: jiangshanlai@gmail.com, paulmck@kernel.org
Cc: josh@joshtriplett.org, rostedt@goodmis.org,
mathieu.desnoyers@efficios.com, rcu@vger.kernel.org,
linux-kernel@vger.kernel.org, Kunwu Chan <kunwu.chan@gmail.com>,
Zqiang <qiang.zhang@linux.dev>
Subject: [PATCH 1/5] rcutorture: Add atomic SRCU lockdep support
Date: Mon, 14 Sep 2026 17:34:15 +0800 [thread overview]
Message-ID: <20260914093419.1474829-2-kunwu.chan@gmail.com> (raw)
In-Reply-To: <20260914093419.1474829-1-kunwu.chan@gmail.com>
Add three testtypes covering atomic SRCU lockdep behavior:
testtype 4: atomic SRCU same-type deadlock
testtype 5: atomic SRCU + raw spinlock dependency cycle
testtype 6: synchronize_srcu_atomic() inside rcu_read_lock()
Co-developed-by: Zqiang <qiang.zhang@linux.dev>
Signed-off-by: Zqiang <qiang.zhang@linux.dev>
Signed-off-by: Kunwu Chan <kunwu.chan@gmail.com>
---
kernel/rcu/rcutorture.c | 84 ++++++++++++++++++++++++++++++++++++++++-
1 file changed, 83 insertions(+), 1 deletion(-)
diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index d795e07a12ad..ac9c726cb391 100644
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -4662,6 +4662,17 @@ static DECLARE_RWSEM(rwsem7);
static DECLARE_RWSEM(rwsem8);
static DECLARE_RWSEM(rwsem9);
+static DEFINE_RAW_SPINLOCK(spin0);
+static DEFINE_RAW_SPINLOCK(spin1);
+static DEFINE_RAW_SPINLOCK(spin2);
+static DEFINE_RAW_SPINLOCK(spin3);
+static DEFINE_RAW_SPINLOCK(spin4);
+static DEFINE_RAW_SPINLOCK(spin5);
+static DEFINE_RAW_SPINLOCK(spin6);
+static DEFINE_RAW_SPINLOCK(spin7);
+static DEFINE_RAW_SPINLOCK(spin8);
+static DEFINE_RAW_SPINLOCK(spin9);
+
DEFINE_STATIC_SRCU(srcu0);
DEFINE_STATIC_SRCU(srcu1);
DEFINE_STATIC_SRCU(srcu2);
@@ -4673,6 +4684,17 @@ DEFINE_STATIC_SRCU(srcu7);
DEFINE_STATIC_SRCU(srcu8);
DEFINE_STATIC_SRCU(srcu9);
+DEFINE_STATIC_SRCU_ATOMIC(srcu0_atomic);
+DEFINE_STATIC_SRCU_ATOMIC(srcu1_atomic);
+DEFINE_STATIC_SRCU_ATOMIC(srcu2_atomic);
+DEFINE_STATIC_SRCU_ATOMIC(srcu3_atomic);
+DEFINE_STATIC_SRCU_ATOMIC(srcu4_atomic);
+DEFINE_STATIC_SRCU_ATOMIC(srcu5_atomic);
+DEFINE_STATIC_SRCU_ATOMIC(srcu6_atomic);
+DEFINE_STATIC_SRCU_ATOMIC(srcu7_atomic);
+DEFINE_STATIC_SRCU_ATOMIC(srcu8_atomic);
+DEFINE_STATIC_SRCU_ATOMIC(srcu9_atomic);
+
static int srcu_lockdep_next(const char *f, const char *fl, const char *fs, const char *fu, int i,
int cyclelen, int deadlock)
{
@@ -4702,6 +4724,12 @@ static void rcu_torture_init_srcu_lockdep(void)
&rwsem5, &rwsem6, &rwsem7, &rwsem8, &rwsem9 };
struct srcu_struct *srcus[] = { &srcu0, &srcu1, &srcu2, &srcu3, &srcu4,
&srcu5, &srcu6, &srcu7, &srcu8, &srcu9 };
+ raw_spinlock_t *spins[] = { &spin0, &spin1, &spin2, &spin3, &spin4,
+ &spin5, &spin6, &spin7, &spin8, &spin9 };
+ struct srcu_struct *srcus_atomic[] = { &srcu0_atomic, &srcu1_atomic, &srcu2_atomic,
+ &srcu3_atomic, &srcu4_atomic, &srcu5_atomic,
+ &srcu6_atomic, &srcu7_atomic, &srcu8_atomic,
+ &srcu9_atomic };
int testtype;
if (!test_srcu_lockdep)
@@ -4812,11 +4840,65 @@ static void rcu_torture_init_srcu_lockdep(void)
}
#endif // #ifdef CONFIG_TASKS_TRACE_RCU
+ if (testtype == 4) {
+ pr_info("%s: test_srcu_lockdep = %05d: SRCU_ATOMIC %d-way %sdeadlock.\n",
+ __func__, test_srcu_lockdep, cyclelen, deadlock ? "" : "non-");
+ if (deadlock && cyclelen == 1)
+ pr_info("%s: Expect hang.\n", __func__);
+ for (i = 0; i < cyclelen; i++) {
+ j = srcu_lockdep_next(__func__, "srcu_read_lock_atomic",
+ "synchronize_srcu_atomic",
+ "srcu_read_unlock_atomic", i,
+ cyclelen, deadlock);
+ idx = srcu_read_lock_atomic(srcus_atomic[i]);
+ if (j >= 0)
+ synchronize_srcu_atomic(srcus_atomic[j]);
+ srcu_read_unlock_atomic(srcus_atomic[i], idx);
+ }
+ return;
+ }
+
+ if (testtype == 5) {
+ pr_info("%s: test_srcu_lockdep = %05d: SRCU_ATOMIC/raw_spinlock %d-way %sdeadlock.\n",
+ __func__, test_srcu_lockdep, cyclelen, deadlock ? "" : "non-");
+ for (i = 0; i < cyclelen; i++) {
+ pr_info("%s: srcu_read_lock_atomic(%d), raw_spin_lock(%d), raw_spin_unlock(%d), srcu_read_unlock_atomic(%d)\n",
+ __func__, i, i, i, i);
+ idx = srcu_read_lock_atomic(srcus_atomic[i]);
+ raw_spin_lock(spins[i]);
+ raw_spin_unlock(spins[i]);
+ srcu_read_unlock_atomic(srcus_atomic[i], idx);
+
+ j = srcu_lockdep_next(__func__, "raw_spin_lock",
+ "synchronize_srcu_atomic",
+ "raw_spin_unlock", i, cyclelen,
+ deadlock);
+ raw_spin_lock(spins[i]);
+ if (j >= 0)
+ synchronize_srcu_atomic(srcus_atomic[j]);
+ raw_spin_unlock(spins[i]);
+ }
+ return;
+ }
+
+ if (testtype == 6) {
+ pr_info("%s: test_srcu_lockdep = %05d: synchronize_srcu_atomic() inside rcu_read_lock() %d-way.\n",
+ __func__, test_srcu_lockdep, cyclelen);
+ for (i = 0; i < cyclelen; i++) {
+ rcu_read_lock();
+ synchronize_srcu_atomic(srcus_atomic[i]);
+ rcu_read_unlock();
+ }
+ return;
+ }
+
err_out:
pr_info("%s: test_srcu_lockdep = %05d does nothing.\n", __func__, test_srcu_lockdep);
pr_info("%s: test_srcu_lockdep = DNNL.\n", __func__);
pr_info("%s: D: Deadlock if nonzero.\n", __func__);
- pr_info("%s: NN: Test number, 0=SRCU, 1=SRCU/mutex, 2=SRCU/rwsem, 3=SRCU/Tasks Trace RCU.\n", __func__);
+ pr_info("%s: NN: Test number, 0=SRCU, 1=SRCU/mutex, 2=SRCU/rwsem, 3=SRCU/Tasks Trace RCU, 4=SRCU_ATOMIC, ",
+ __func__);
+ pr_cont("5=SRCU_ATOMIC/raw_spinlock, 6=synchronize_srcu_atomic inside rcu_read_lock.\n");
pr_info("%s: L: Cycle length.\n", __func__);
if (!IS_ENABLED(CONFIG_TASKS_TRACE_RCU))
pr_info("%s: NN=3 disallowed because kernel is built with CONFIG_TASKS_TRACE_RCU=n\n", __func__);
--
2.43.0
next prev parent reply other threads:[~2026-09-14 9:34 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-14 9:34 [PATCH 0/5] srcu: Add lockdep coverage for atomic SRCU and fix IRQ-state bug Kunwu Chan
2026-09-14 9:34 ` Kunwu Chan [this message]
2026-09-14 9:34 ` [PATCH 2/5] selftests/rcutorture: Wire atomic SRCU into srcu_lockdep.sh Kunwu Chan
2026-09-14 9:34 ` [PATCH 3/5] srcutree: Preserve IRQ state in synchronize_srcu_atomic() callchain Kunwu Chan
2026-09-14 9:34 ` [PATCH 4/5] selftests/rcutorture: Fix double nerrs count in srcu_lockdep.sh Kunwu Chan
2026-09-14 9:34 ` [PATCH 5/5] rcutorture: Add atomic SRCU cross-CPU IRQ context mismatch test Kunwu Chan
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