Merge tag 'rcu-fixes.v7.0-20260325a' of git://git.kernel.org/pub/scm/linux/kernel/git/rcu/linux

Pull RCU fixes from Boqun Feng:
 "Fix a regression introduced by commit c27cea4416a3 ("rcu: Re-implement
  RCU Tasks Trace in terms of SRCU-fast"): BPF contexts can run with
  preemption disabled or scheduler locks held, so call_srcu() must work
  in all such contexts.

  Fix this by converting SRCU's spinlocks to raw spinlocks and avoiding
  scheduler lock acquisition in call_srcu() by deferring to an irq_work
  (similar to call_rcu_tasks_generic()), for both tree SRCU and tiny
  SRCU.

  Also fix a follow-on lockdep splat caused by srcu_node allocation
  under the newly introduced raw spinlock by deferring the allocation to
  grace-period worker context"

* tag 'rcu-fixes.v7.0-20260325a' of git://git.kernel.org/pub/scm/linux/kernel/git/rcu/linux:
  srcu: Use irq_work to start GP in tiny SRCU
  rcu: Use an intermediate irq_work to start process_srcu()
  srcu: Push srcu_node allocation to GP when non-preemptible
  srcu: Use raw spinlocks so call_srcu() can be used under preempt_disable()

3 files changed, 129 insertions, 110 deletions

diff --git a/kernel/rcu/rcu.h b/kernel/rcu/rcu.h
index dc5d614b372c..9b10b57b79ad 100644
--- a/kernel/rcu/rcu.h
+++ b/kernel/rcu/rcu.h
@@ -502,6 +502,15 @@ do {									\
 	___locked;							\
 })
 
+#define raw_spin_trylock_irqsave_rcu_node(p, flags)			\
+({									\
+	bool ___locked = raw_spin_trylock_irqsave(&ACCESS_PRIVATE(p, lock), flags); \
+									\
+	if (___locked)							\
+		smp_mb__after_unlock_lock();				\
+	___locked;							\
+})
+
 #define raw_lockdep_assert_held_rcu_node(p)				\
 	lockdep_assert_held(&ACCESS_PRIVATE(p, lock))
 
diff --git a/kernel/rcu/srcutiny.c b/kernel/rcu/srcutiny.c
index 3450c3751ef7..a2e2d516e51b 100644
--- a/kernel/rcu/srcutiny.c
+++ b/kernel/rcu/srcutiny.c
@@ -9,6 +9,7 @@
  */
 
 #include <linux/export.h>
+#include <linux/irq_work.h>
 #include <linux/mutex.h>
 #include <linux/preempt.h>
 #include <linux/rcupdate_wait.h>
@@ -41,6 +42,7 @@ static int init_srcu_struct_fields(struct srcu_struct *ssp)
 	ssp->srcu_idx_max = 0;
 	INIT_WORK(&ssp->srcu_work, srcu_drive_gp);
 	INIT_LIST_HEAD(&ssp->srcu_work.entry);
+	init_irq_work(&ssp->srcu_irq_work, srcu_tiny_irq_work);
 	return 0;
 }
 
@@ -84,6 +86,7 @@ EXPORT_SYMBOL_GPL(init_srcu_struct);
 void cleanup_srcu_struct(struct srcu_struct *ssp)
 {
 	WARN_ON(ssp->srcu_lock_nesting[0] || ssp->srcu_lock_nesting[1]);
+	irq_work_sync(&ssp->srcu_irq_work);
 	flush_work(&ssp->srcu_work);
 	WARN_ON(ssp->srcu_gp_running);
 	WARN_ON(ssp->srcu_gp_waiting);
@@ -177,6 +180,20 @@ void srcu_drive_gp(struct work_struct *wp)
 }
 EXPORT_SYMBOL_GPL(srcu_drive_gp);
 
+/*
+ * Use an irq_work to defer schedule_work() to avoid acquiring the workqueue
+ * pool->lock while the caller might hold scheduler locks, causing lockdep
+ * splats due to workqueue_init() doing a wakeup.
+ */
+void srcu_tiny_irq_work(struct irq_work *irq_work)
+{
+	struct srcu_struct *ssp;
+
+	ssp = container_of(irq_work, struct srcu_struct, srcu_irq_work);
+	schedule_work(&ssp->srcu_work);
+}
+EXPORT_SYMBOL_GPL(srcu_tiny_irq_work);
+
 static void srcu_gp_start_if_needed(struct srcu_struct *ssp)
 {
 	unsigned long cookie;
@@ -189,7 +206,7 @@ static void srcu_gp_start_if_needed(struct srcu_struct *ssp)
 	WRITE_ONCE(ssp->srcu_idx_max, cookie);
 	if (!READ_ONCE(ssp->srcu_gp_running)) {
 		if (likely(srcu_init_done))
-			schedule_work(&ssp->srcu_work);
+			irq_work_queue(&ssp->srcu_irq_work);
 		else if (list_empty(&ssp->srcu_work.entry))
 			list_add(&ssp->srcu_work.entry, &srcu_boot_list);
 	}
diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c
index aef8e91ad33e..0d01cd8c4b4a 100644
--- a/kernel/rcu/srcutree.c
+++ b/kernel/rcu/srcutree.c
@@ -19,6 +19,7 @@
 #include <linux/mutex.h>
 #include <linux/percpu.h>
 #include <linux/preempt.h>
+#include <linux/irq_work.h>
 #include <linux/rcupdate_wait.h>
 #include <linux/sched.h>
 #include <linux/smp.h>
@@ -75,44 +76,9 @@ static bool __read_mostly srcu_init_done;
 static void srcu_invoke_callbacks(struct work_struct *work);
 static void srcu_reschedule(struct srcu_struct *ssp, unsigned long delay);
 static void process_srcu(struct work_struct *work);
+static void srcu_irq_work(struct irq_work *work);
 static void srcu_delay_timer(struct timer_list *t);
 
-/* Wrappers for lock acquisition and release, see raw_spin_lock_rcu_node(). */
-#define spin_lock_rcu_node(p)							\
-do {										\
-	spin_lock(&ACCESS_PRIVATE(p, lock));					\
-	smp_mb__after_unlock_lock();						\
-} while (0)
-
-#define spin_unlock_rcu_node(p) spin_unlock(&ACCESS_PRIVATE(p, lock))
-
-#define spin_lock_irq_rcu_node(p)						\
-do {										\
-	spin_lock_irq(&ACCESS_PRIVATE(p, lock));				\
-	smp_mb__after_unlock_lock();						\
-} while (0)
-
-#define spin_unlock_irq_rcu_node(p)						\
-	spin_unlock_irq(&ACCESS_PRIVATE(p, lock))
-
-#define spin_lock_irqsave_rcu_node(p, flags)					\
-do {										\
-	spin_lock_irqsave(&ACCESS_PRIVATE(p, lock), flags);			\
-	smp_mb__after_unlock_lock();						\
-} while (0)
-
-#define spin_trylock_irqsave_rcu_node(p, flags)					\
-({										\
-	bool ___locked = spin_trylock_irqsave(&ACCESS_PRIVATE(p, lock), flags); \
-										\
-	if (___locked)								\
-		smp_mb__after_unlock_lock();					\
-	___locked;								\
-})
-
-#define spin_unlock_irqrestore_rcu_node(p, flags)				\
-	spin_unlock_irqrestore(&ACCESS_PRIVATE(p, lock), flags)			\
-
 /*
  * Initialize SRCU per-CPU data.  Note that statically allocated
  * srcu_struct structures might already have srcu_read_lock() and
@@ -131,7 +97,7 @@ static void init_srcu_struct_data(struct srcu_struct *ssp)
 	 */
 	for_each_possible_cpu(cpu) {
 		sdp = per_cpu_ptr(ssp->sda, cpu);
-		spin_lock_init(&ACCESS_PRIVATE(sdp, lock));
+		raw_spin_lock_init(&ACCESS_PRIVATE(sdp, lock));
 		rcu_segcblist_init(&sdp->srcu_cblist);
 		sdp->srcu_cblist_invoking = false;
 		sdp->srcu_gp_seq_needed = ssp->srcu_sup->srcu_gp_seq;
@@ -186,7 +152,7 @@ static bool init_srcu_struct_nodes(struct srcu_struct *ssp, gfp_t gfp_flags)
 
 	/* Each pass through this loop initializes one srcu_node structure. */
 	srcu_for_each_node_breadth_first(ssp, snp) {
-		spin_lock_init(&ACCESS_PRIVATE(snp, lock));
+		raw_spin_lock_init(&ACCESS_PRIVATE(snp, lock));
 		BUILD_BUG_ON(ARRAY_SIZE(snp->srcu_have_cbs) !=
 			     ARRAY_SIZE(snp->srcu_data_have_cbs));
 		for (i = 0; i < ARRAY_SIZE(snp->srcu_have_cbs); i++) {
@@ -242,7 +208,7 @@ static int init_srcu_struct_fields(struct srcu_struct *ssp, bool is_static)
 	if (!ssp->srcu_sup)
 		return -ENOMEM;
 	if (!is_static)
-		spin_lock_init(&ACCESS_PRIVATE(ssp->srcu_sup, lock));
+		raw_spin_lock_init(&ACCESS_PRIVATE(ssp->srcu_sup, lock));
 	ssp->srcu_sup->srcu_size_state = SRCU_SIZE_SMALL;
 	ssp->srcu_sup->node = NULL;
 	mutex_init(&ssp->srcu_sup->srcu_cb_mutex);
@@ -252,6 +218,7 @@ static int init_srcu_struct_fields(struct srcu_struct *ssp, bool is_static)
 	mutex_init(&ssp->srcu_sup->srcu_barrier_mutex);
 	atomic_set(&ssp->srcu_sup->srcu_barrier_cpu_cnt, 0);
 	INIT_DELAYED_WORK(&ssp->srcu_sup->work, process_srcu);
+	init_irq_work(&ssp->srcu_sup->irq_work, srcu_irq_work);
 	ssp->srcu_sup->sda_is_static = is_static;
 	if (!is_static) {
 		ssp->sda = alloc_percpu(struct srcu_data);
@@ -263,9 +230,12 @@ static int init_srcu_struct_fields(struct srcu_struct *ssp, bool is_static)
 	ssp->srcu_sup->srcu_gp_seq_needed_exp = SRCU_GP_SEQ_INITIAL_VAL;
 	ssp->srcu_sup->srcu_last_gp_end = ktime_get_mono_fast_ns();
 	if (READ_ONCE(ssp->srcu_sup->srcu_size_state) == SRCU_SIZE_SMALL && SRCU_SIZING_IS_INIT()) {
-		if (!init_srcu_struct_nodes(ssp, is_static ? GFP_ATOMIC : GFP_KERNEL))
+		if (!preemptible())
+			WRITE_ONCE(ssp->srcu_sup->srcu_size_state, SRCU_SIZE_ALLOC);
+		else if (init_srcu_struct_nodes(ssp, GFP_KERNEL))
+			WRITE_ONCE(ssp->srcu_sup->srcu_size_state, SRCU_SIZE_BIG);
+		else
 			goto err_free_sda;
-		WRITE_ONCE(ssp->srcu_sup->srcu_size_state, SRCU_SIZE_BIG);
 	}
 	ssp->srcu_sup->srcu_ssp = ssp;
 	smp_store_release(&ssp->srcu_sup->srcu_gp_seq_needed,
@@ -394,20 +364,20 @@ static void srcu_transition_to_big(struct srcu_struct *ssp)
 	/* Double-checked locking on ->srcu_size-state. */
 	if (smp_load_acquire(&ssp->srcu_sup->srcu_size_state) != SRCU_SIZE_SMALL)
 		return;
-	spin_lock_irqsave_rcu_node(ssp->srcu_sup, flags);
+	raw_spin_lock_irqsave_rcu_node(ssp->srcu_sup, flags);
 	if (smp_load_acquire(&ssp->srcu_sup->srcu_size_state) != SRCU_SIZE_SMALL) {
-		spin_unlock_irqrestore_rcu_node(ssp->srcu_sup, flags);
+		raw_spin_unlock_irqrestore_rcu_node(ssp->srcu_sup, flags);
 		return;
 	}
 	__srcu_transition_to_big(ssp);
-	spin_unlock_irqrestore_rcu_node(ssp->srcu_sup, flags);
+	raw_spin_unlock_irqrestore_rcu_node(ssp->srcu_sup, flags);
 }
 
 /*
  * Check to see if the just-encountered contention event justifies
  * a transition to SRCU_SIZE_BIG.
  */
-static void spin_lock_irqsave_check_contention(struct srcu_struct *ssp)
+static void raw_spin_lock_irqsave_check_contention(struct srcu_struct *ssp)
 {
 	unsigned long j;
 
@@ -429,16 +399,16 @@ static void spin_lock_irqsave_check_contention(struct srcu_struct *ssp)
  * to SRCU_SIZE_BIG.  But only if the srcutree.convert_to_big module
  * parameter permits this.
  */
-static void spin_lock_irqsave_sdp_contention(struct srcu_data *sdp, unsigned long *flags)
+static void raw_spin_lock_irqsave_sdp_contention(struct srcu_data *sdp, unsigned long *flags)
 {
 	struct srcu_struct *ssp = sdp->ssp;
 
-	if (spin_trylock_irqsave_rcu_node(sdp, *flags))
+	if (raw_spin_trylock_irqsave_rcu_node(sdp, *flags))
 		return;
-	spin_lock_irqsave_rcu_node(ssp->srcu_sup, *flags);
-	spin_lock_irqsave_check_contention(ssp);
-	spin_unlock_irqrestore_rcu_node(ssp->srcu_sup, *flags);
-	spin_lock_irqsave_rcu_node(sdp, *flags);
+	raw_spin_lock_irqsave_rcu_node(ssp->srcu_sup, *flags);
+	raw_spin_lock_irqsave_check_contention(ssp);
+	raw_spin_unlock_irqrestore_rcu_node(ssp->srcu_sup, *flags);
+	raw_spin_lock_irqsave_rcu_node(sdp, *flags);
 }
 
 /*
@@ -447,12 +417,12 @@ static void spin_lock_irqsave_sdp_contention(struct srcu_data *sdp, unsigned lon
  * to SRCU_SIZE_BIG.  But only if the srcutree.convert_to_big module
  * parameter permits this.
  */
-static void spin_lock_irqsave_ssp_contention(struct srcu_struct *ssp, unsigned long *flags)
+static void raw_spin_lock_irqsave_ssp_contention(struct srcu_struct *ssp, unsigned long *flags)
 {
-	if (spin_trylock_irqsave_rcu_node(ssp->srcu_sup, *flags))
+	if (raw_spin_trylock_irqsave_rcu_node(ssp->srcu_sup, *flags))
 		return;
-	spin_lock_irqsave_rcu_node(ssp->srcu_sup, *flags);
-	spin_lock_irqsave_check_contention(ssp);
+	raw_spin_lock_irqsave_rcu_node(ssp->srcu_sup, *flags);
+	raw_spin_lock_irqsave_check_contention(ssp);
 }
 
 /*
@@ -470,13 +440,13 @@ static void check_init_srcu_struct(struct srcu_struct *ssp)
 	/* The smp_load_acquire() pairs with the smp_store_release(). */
 	if (!rcu_seq_state(smp_load_acquire(&ssp->srcu_sup->srcu_gp_seq_needed))) /*^^^*/
 		return; /* Already initialized. */
-	spin_lock_irqsave_rcu_node(ssp->srcu_sup, flags);
+	raw_spin_lock_irqsave_rcu_node(ssp->srcu_sup, flags);
 	if (!rcu_seq_state(ssp->srcu_sup->srcu_gp_seq_needed)) {
-		spin_unlock_irqrestore_rcu_node(ssp->srcu_sup, flags);
+		raw_spin_unlock_irqrestore_rcu_node(ssp->srcu_sup, flags);
 		return;
 	}
 	init_srcu_struct_fields(ssp, true);
-	spin_unlock_irqrestore_rcu_node(ssp->srcu_sup, flags);
+	raw_spin_unlock_irqrestore_rcu_node(ssp->srcu_sup, flags);
 }
 
 /*
@@ -742,13 +712,15 @@ void cleanup_srcu_struct(struct srcu_struct *ssp)
 	unsigned long delay;
 	struct srcu_usage *sup = ssp->srcu_sup;
 
-	spin_lock_irq_rcu_node(ssp->srcu_sup);
+	raw_spin_lock_irq_rcu_node(ssp->srcu_sup);
 	delay = srcu_get_delay(ssp);
-	spin_unlock_irq_rcu_node(ssp->srcu_sup);
+	raw_spin_unlock_irq_rcu_node(ssp->srcu_sup);
 	if (WARN_ON(!delay))
 		return; /* Just leak it! */
 	if (WARN_ON(srcu_readers_active(ssp)))
 		return; /* Just leak it! */
+	/* Wait for irq_work to finish first as it may queue a new work. */
+	irq_work_sync(&sup->irq_work);
 	flush_delayed_work(&sup->work);
 	for_each_possible_cpu(cpu) {
 		struct srcu_data *sdp = per_cpu_ptr(ssp->sda, cpu);
@@ -960,7 +932,7 @@ static void srcu_gp_end(struct srcu_struct *ssp)
 	mutex_lock(&sup->srcu_cb_mutex);
 
 	/* End the current grace period. */
-	spin_lock_irq_rcu_node(sup);
+	raw_spin_lock_irq_rcu_node(sup);
 	idx = rcu_seq_state(sup->srcu_gp_seq);
 	WARN_ON_ONCE(idx != SRCU_STATE_SCAN2);
 	if (srcu_gp_is_expedited(ssp))
@@ -971,7 +943,7 @@ static void srcu_gp_end(struct srcu_struct *ssp)
 	gpseq = rcu_seq_current(&sup->srcu_gp_seq);
 	if (ULONG_CMP_LT(sup->srcu_gp_seq_needed_exp, gpseq))
 		WRITE_ONCE(sup->srcu_gp_seq_needed_exp, gpseq);
-	spin_unlock_irq_rcu_node(sup);
+	raw_spin_unlock_irq_rcu_node(sup);
 	mutex_unlock(&sup->srcu_gp_mutex);
 	/* A new grace period can start at this point.  But only one. */
 
@@ -983,7 +955,7 @@ static void srcu_gp_end(struct srcu_struct *ssp)
 	} else {
 		idx = rcu_seq_ctr(gpseq) % ARRAY_SIZE(snp->srcu_have_cbs);
 		srcu_for_each_node_breadth_first(ssp, snp) {
-			spin_lock_irq_rcu_node(snp);
+			raw_spin_lock_irq_rcu_node(snp);
 			cbs = false;
 			last_lvl = snp >= sup->level[rcu_num_lvls - 1];
 			if (last_lvl)
@@ -998,7 +970,7 @@ static void srcu_gp_end(struct srcu_struct *ssp)
 			else
 				mask = snp->srcu_data_have_cbs[idx];
 			snp->srcu_data_have_cbs[idx] = 0;
-			spin_unlock_irq_rcu_node(snp);
+			raw_spin_unlock_irq_rcu_node(snp);
 			if (cbs)
 				srcu_schedule_cbs_snp(ssp, snp, mask, cbdelay);
 		}
@@ -1008,27 +980,27 @@ static void srcu_gp_end(struct srcu_struct *ssp)
 	if (!(gpseq & counter_wrap_check))
 		for_each_possible_cpu(cpu) {
 			sdp = per_cpu_ptr(ssp->sda, cpu);
-			spin_lock_irq_rcu_node(sdp);
+			raw_spin_lock_irq_rcu_node(sdp);
 			if (ULONG_CMP_GE(gpseq, sdp->srcu_gp_seq_needed + 100))
 				sdp->srcu_gp_seq_needed = gpseq;
 			if (ULONG_CMP_GE(gpseq, sdp->srcu_gp_seq_needed_exp + 100))
 				sdp->srcu_gp_seq_needed_exp = gpseq;
-			spin_unlock_irq_rcu_node(sdp);
+			raw_spin_unlock_irq_rcu_node(sdp);
 		}
 
 	/* Callback initiation done, allow grace periods after next. */
 	mutex_unlock(&sup->srcu_cb_mutex);
 
 	/* Start a new grace period if needed. */
-	spin_lock_irq_rcu_node(sup);
+	raw_spin_lock_irq_rcu_node(sup);
 	gpseq = rcu_seq_current(&sup->srcu_gp_seq);
 	if (!rcu_seq_state(gpseq) &&
 	    ULONG_CMP_LT(gpseq, sup->srcu_gp_seq_needed)) {
 		srcu_gp_start(ssp);
-		spin_unlock_irq_rcu_node(sup);
+		raw_spin_unlock_irq_rcu_node(sup);
 		srcu_reschedule(ssp, 0);
 	} else {
-		spin_unlock_irq_rcu_node(sup);
+		raw_spin_unlock_irq_rcu_node(sup);
 	}
 
 	/* Transition to big if needed. */
@@ -1059,19 +1031,19 @@ static void srcu_funnel_exp_start(struct srcu_struct *ssp, struct srcu_node *snp
 			if (WARN_ON_ONCE(rcu_seq_done(&ssp->srcu_sup->srcu_gp_seq, s)) ||
 			    (!srcu_invl_snp_seq(sgsne) && ULONG_CMP_GE(sgsne, s)))
 				return;
-			spin_lock_irqsave_rcu_node(snp, flags);
+			raw_spin_lock_irqsave_rcu_node(snp, flags);
 			sgsne = snp->srcu_gp_seq_needed_exp;
 			if (!srcu_invl_snp_seq(sgsne) && ULONG_CMP_GE(sgsne, s)) {
-				spin_unlock_irqrestore_rcu_node(snp, flags);
+				raw_spin_unlock_irqrestore_rcu_node(snp, flags);
 				return;
 			}
 			WRITE_ONCE(snp->srcu_gp_seq_needed_exp, s);
-			spin_unlock_irqrestore_rcu_node(snp, flags);
+			raw_spin_unlock_irqrestore_rcu_node(snp, flags);
 		}
-	spin_lock_irqsave_ssp_contention(ssp, &flags);
+	raw_spin_lock_irqsave_ssp_contention(ssp, &flags);
 	if (ULONG_CMP_LT(ssp->srcu_sup->srcu_gp_seq_needed_exp, s))
 		WRITE_ONCE(ssp->srcu_sup->srcu_gp_seq_needed_exp, s);
-	spin_unlock_irqrestore_rcu_node(ssp->srcu_sup, flags);
+	raw_spin_unlock_irqrestore_rcu_node(ssp->srcu_sup, flags);
 }
 
 /*
@@ -1109,12 +1081,12 @@ static void srcu_funnel_gp_start(struct srcu_struct *ssp, struct srcu_data *sdp,
 		for (snp = snp_leaf; snp != NULL; snp = snp->srcu_parent) {
 			if (WARN_ON_ONCE(rcu_seq_done(&sup->srcu_gp_seq, s)) && snp != snp_leaf)
 				return; /* GP already done and CBs recorded. */
-			spin_lock_irqsave_rcu_node(snp, flags);
+			raw_spin_lock_irqsave_rcu_node(snp, flags);
 			snp_seq = snp->srcu_have_cbs[idx];
 			if (!srcu_invl_snp_seq(snp_seq) && ULONG_CMP_GE(snp_seq, s)) {
 				if (snp == snp_leaf && snp_seq == s)
 					snp->srcu_data_have_cbs[idx] |= sdp->grpmask;
-				spin_unlock_irqrestore_rcu_node(snp, flags);
+				raw_spin_unlock_irqrestore_rcu_node(snp, flags);
 				if (snp == snp_leaf && snp_seq != s) {
 					srcu_schedule_cbs_sdp(sdp, do_norm ? SRCU_INTERVAL : 0);
 					return;
@@ -1129,11 +1101,11 @@ static void srcu_funnel_gp_start(struct srcu_struct *ssp, struct srcu_data *sdp,
 			sgsne = snp->srcu_gp_seq_needed_exp;
 			if (!do_norm && (srcu_invl_snp_seq(sgsne) || ULONG_CMP_LT(sgsne, s)))
 				WRITE_ONCE(snp->srcu_gp_seq_needed_exp, s);
-			spin_unlock_irqrestore_rcu_node(snp, flags);
+			raw_spin_unlock_irqrestore_rcu_node(snp, flags);
 		}
 
 	/* Top of tree, must ensure the grace period will be started. */
-	spin_lock_irqsave_ssp_contention(ssp, &flags);
+	raw_spin_lock_irqsave_ssp_contention(ssp, &flags);
 	if (ULONG_CMP_LT(sup->srcu_gp_seq_needed, s)) {
 		/*
 		 * Record need for grace period s.  Pair with load
@@ -1154,13 +1126,17 @@ static void srcu_funnel_gp_start(struct srcu_struct *ssp, struct srcu_data *sdp,
 		// it isn't.  And it does not have to be.  After all, it
 		// can only be executed during early boot when there is only
 		// the one boot CPU running with interrupts still disabled.
+		//
+		// Use an irq_work here to avoid acquiring runqueue lock with
+		// srcu rcu_node::lock held. BPF instrument could introduce the
+		// opposite dependency, hence we need to break the possible
+		// locking dependency here.
 		if (likely(srcu_init_done))
-			queue_delayed_work(rcu_gp_wq, &sup->work,
-					   !!srcu_get_delay(ssp));
+			irq_work_queue(&sup->irq_work);
 		else if (list_empty(&sup->work.work.entry))
 			list_add(&sup->work.work.entry, &srcu_boot_list);
 	}
-	spin_unlock_irqrestore_rcu_node(sup, flags);
+	raw_spin_unlock_irqrestore_rcu_node(sup, flags);
 }
 
 /*
@@ -1172,9 +1148,9 @@ static bool try_check_zero(struct srcu_struct *ssp, int idx, int trycount)
 {
 	unsigned long curdelay;
 
-	spin_lock_irq_rcu_node(ssp->srcu_sup);
+	raw_spin_lock_irq_rcu_node(ssp->srcu_sup);
 	curdelay = !srcu_get_delay(ssp);
-	spin_unlock_irq_rcu_node(ssp->srcu_sup);
+	raw_spin_unlock_irq_rcu_node(ssp->srcu_sup);
 
 	for (;;) {
 		if (srcu_readers_active_idx_check(ssp, idx))
@@ -1285,12 +1261,12 @@ static bool srcu_should_expedite(struct srcu_struct *ssp)
 		return false;
 	/* If the local srcu_data structure has callbacks, not idle.  */
 	sdp = raw_cpu_ptr(ssp->sda);
-	spin_lock_irqsave_rcu_node(sdp, flags);
+	raw_spin_lock_irqsave_rcu_node(sdp, flags);
 	if (rcu_segcblist_pend_cbs(&sdp->srcu_cblist)) {
-		spin_unlock_irqrestore_rcu_node(sdp, flags);
+		raw_spin_unlock_irqrestore_rcu_node(sdp, flags);
 		return false; /* Callbacks already present, so not idle. */
 	}
-	spin_unlock_irqrestore_rcu_node(sdp, flags);
+	raw_spin_unlock_irqrestore_rcu_node(sdp, flags);
 
 	/*
 	 * No local callbacks, so probabilistically probe global state.
@@ -1350,7 +1326,7 @@ static unsigned long srcu_gp_start_if_needed(struct srcu_struct *ssp,
 		sdp = per_cpu_ptr(ssp->sda, get_boot_cpu_id());
 	else
 		sdp = raw_cpu_ptr(ssp->sda);
-	spin_lock_irqsave_sdp_contention(sdp, &flags);
+	raw_spin_lock_irqsave_sdp_contention(sdp, &flags);
 	if (rhp)
 		rcu_segcblist_enqueue(&sdp->srcu_cblist, rhp);
 	/*
@@ -1410,7 +1386,7 @@ static unsigned long srcu_gp_start_if_needed(struct srcu_struct *ssp,
 		sdp->srcu_gp_seq_needed_exp = s;
 		needexp = true;
 	}
-	spin_unlock_irqrestore_rcu_node(sdp, flags);
+	raw_spin_unlock_irqrestore_rcu_node(sdp, flags);
 
 	/* Ensure that snp node tree is fully initialized before traversing it */
 	if (ss_state < SRCU_SIZE_WAIT_BARRIER)
@@ -1522,7 +1498,7 @@ static void __synchronize_srcu(struct srcu_struct *ssp, bool do_norm)
 
 	/*
 	 * Make sure that later code is ordered after the SRCU grace
-	 * period.  This pairs with the spin_lock_irq_rcu_node()
+	 * period.  This pairs with the raw_spin_lock_irq_rcu_node()
 	 * in srcu_invoke_callbacks().  Unlike Tree RCU, this is needed
 	 * because the current CPU might have been totally uninvolved with
 	 * (and thus unordered against) that grace period.
@@ -1701,7 +1677,7 @@ static void srcu_barrier_cb(struct rcu_head *rhp)
  */
 static void srcu_barrier_one_cpu(struct srcu_struct *ssp, struct srcu_data *sdp)
 {
-	spin_lock_irq_rcu_node(sdp);
+	raw_spin_lock_irq_rcu_node(sdp);
 	atomic_inc(&ssp->srcu_sup->srcu_barrier_cpu_cnt);
 	sdp->srcu_barrier_head.func = srcu_barrier_cb;
 	debug_rcu_head_queue(&sdp->srcu_barrier_head);
@@ -1710,7 +1686,7 @@ static void srcu_barrier_one_cpu(struct srcu_struct *ssp, struct srcu_data *sdp)
 		debug_rcu_head_unqueue(&sdp->srcu_barrier_head);
 		atomic_dec(&ssp->srcu_sup->srcu_barrier_cpu_cnt);
 	}
-	spin_unlock_irq_rcu_node(sdp);
+	raw_spin_unlock_irq_rcu_node(sdp);
 }
 
 /**
@@ -1761,7 +1737,7 @@ static void srcu_expedite_current_cb(struct rcu_head *rhp)
 	bool needcb = false;
 	struct srcu_data *sdp = container_of(rhp, struct srcu_data, srcu_ec_head);
 
-	spin_lock_irqsave_sdp_contention(sdp, &flags);
+	raw_spin_lock_irqsave_sdp_contention(sdp, &flags);
 	if (sdp->srcu_ec_state == SRCU_EC_IDLE) {
 		WARN_ON_ONCE(1);
 	} else if (sdp->srcu_ec_state == SRCU_EC_PENDING) {
@@ -1771,7 +1747,7 @@ static void srcu_expedite_current_cb(struct rcu_head *rhp)
 		sdp->srcu_ec_state = SRCU_EC_PENDING;
 		needcb = true;
 	}
-	spin_unlock_irqrestore_rcu_node(sdp, flags);
+	raw_spin_unlock_irqrestore_rcu_node(sdp, flags);
 	// If needed, requeue ourselves as an expedited SRCU callback.
 	if (needcb)
 		__call_srcu(sdp->ssp, &sdp->srcu_ec_head, srcu_expedite_current_cb, false);
@@ -1795,7 +1771,7 @@ void srcu_expedite_current(struct srcu_struct *ssp)
 
 	migrate_disable();
 	sdp = this_cpu_ptr(ssp->sda);
-	spin_lock_irqsave_sdp_contention(sdp, &flags);
+	raw_spin_lock_irqsave_sdp_contention(sdp, &flags);
 	if (sdp->srcu_ec_state == SRCU_EC_IDLE) {
 		sdp->srcu_ec_state = SRCU_EC_PENDING;
 		needcb = true;
@@ -1804,7 +1780,7 @@ void srcu_expedite_current(struct srcu_struct *ssp)
 	} else {
 		WARN_ON_ONCE(sdp->srcu_ec_state != SRCU_EC_REPOST);
 	}
-	spin_unlock_irqrestore_rcu_node(sdp, flags);
+	raw_spin_unlock_irqrestore_rcu_node(sdp, flags);
 	// If needed, queue an expedited SRCU callback.
 	if (needcb)
 		__call_srcu(ssp, &sdp->srcu_ec_head, srcu_expedite_current_cb, false);
@@ -1848,17 +1824,17 @@ static void srcu_advance_state(struct srcu_struct *ssp)
 	 */
 	idx = rcu_seq_state(smp_load_acquire(&ssp->srcu_sup->srcu_gp_seq)); /* ^^^ */
 	if (idx == SRCU_STATE_IDLE) {
-		spin_lock_irq_rcu_node(ssp->srcu_sup);
+		raw_spin_lock_irq_rcu_node(ssp->srcu_sup);
 		if (ULONG_CMP_GE(ssp->srcu_sup->srcu_gp_seq, ssp->srcu_sup->srcu_gp_seq_needed)) {
 			WARN_ON_ONCE(rcu_seq_state(ssp->srcu_sup->srcu_gp_seq));
-			spin_unlock_irq_rcu_node(ssp->srcu_sup);
+			raw_spin_unlock_irq_rcu_node(ssp->srcu_sup);
 			mutex_unlock(&ssp->srcu_sup->srcu_gp_mutex);
 			return;
 		}
 		idx = rcu_seq_state(READ_ONCE(ssp->srcu_sup->srcu_gp_seq));
 		if (idx == SRCU_STATE_IDLE)
 			srcu_gp_start(ssp);
-		spin_unlock_irq_rcu_node(ssp->srcu_sup);
+		raw_spin_unlock_irq_rcu_node(ssp->srcu_sup);
 		if (idx != SRCU_STATE_IDLE) {
 			mutex_unlock(&ssp->srcu_sup->srcu_gp_mutex);
 			return; /* Someone else started the grace period. */
@@ -1872,10 +1848,10 @@ static void srcu_advance_state(struct srcu_struct *ssp)
 			return; /* readers present, retry later. */
 		}
 		srcu_flip(ssp);
-		spin_lock_irq_rcu_node(ssp->srcu_sup);
+		raw_spin_lock_irq_rcu_node(ssp->srcu_sup);
 		rcu_seq_set_state(&ssp->srcu_sup->srcu_gp_seq, SRCU_STATE_SCAN2);
 		ssp->srcu_sup->srcu_n_exp_nodelay = 0;
-		spin_unlock_irq_rcu_node(ssp->srcu_sup);
+		raw_spin_unlock_irq_rcu_node(ssp->srcu_sup);
 	}
 
 	if (rcu_seq_state(READ_ONCE(ssp->srcu_sup->srcu_gp_seq)) == SRCU_STATE_SCAN2) {
@@ -1913,7 +1889,7 @@ static void srcu_invoke_callbacks(struct work_struct *work)
 
 	ssp = sdp->ssp;
 	rcu_cblist_init(&ready_cbs);
-	spin_lock_irq_rcu_node(sdp);
+	raw_spin_lock_irq_rcu_node(sdp);
 	WARN_ON_ONCE(!rcu_segcblist_segempty(&sdp->srcu_cblist, RCU_NEXT_TAIL));
 	rcu_segcblist_advance(&sdp->srcu_cblist,
 			      rcu_seq_current(&ssp->srcu_sup->srcu_gp_seq));
@@ -1924,7 +1900,7 @@ static void srcu_invoke_callbacks(struct work_struct *work)
 	 */
 	if (sdp->srcu_cblist_invoking ||
 	    !rcu_segcblist_ready_cbs(&sdp->srcu_cblist)) {
-		spin_unlock_irq_rcu_node(sdp);
+		raw_spin_unlock_irq_rcu_node(sdp);
 		return;  /* Someone else on the job or nothing to do. */
 	}
 
@@ -1932,7 +1908,7 @@ static void srcu_invoke_callbacks(struct work_struct *work)
 	sdp->srcu_cblist_invoking = true;
 	rcu_segcblist_extract_done_cbs(&sdp->srcu_cblist, &ready_cbs);
 	len = ready_cbs.len;
-	spin_unlock_irq_rcu_node(sdp);
+	raw_spin_unlock_irq_rcu_node(sdp);
 	rhp = rcu_cblist_dequeue(&ready_cbs);
 	for (; rhp != NULL; rhp = rcu_cblist_dequeue(&ready_cbs)) {
 		debug_rcu_head_unqueue(rhp);
@@ -1947,11 +1923,11 @@ static void srcu_invoke_callbacks(struct work_struct *work)
 	 * Update counts, accelerate new callbacks, and if needed,
 	 * schedule another round of callback invocation.
 	 */
-	spin_lock_irq_rcu_node(sdp);
+	raw_spin_lock_irq_rcu_node(sdp);
 	rcu_segcblist_add_len(&sdp->srcu_cblist, -len);
 	sdp->srcu_cblist_invoking = false;
 	more = rcu_segcblist_ready_cbs(&sdp->srcu_cblist);
-	spin_unlock_irq_rcu_node(sdp);
+	raw_spin_unlock_irq_rcu_node(sdp);
 	/* An SRCU barrier or callbacks from previous nesting work pending */
 	if (more)
 		srcu_schedule_cbs_sdp(sdp, 0);
@@ -1965,7 +1941,7 @@ static void srcu_reschedule(struct srcu_struct *ssp, unsigned long delay)
 {
 	bool pushgp = true;
 
-	spin_lock_irq_rcu_node(ssp->srcu_sup);
+	raw_spin_lock_irq_rcu_node(ssp->srcu_sup);
 	if (ULONG_CMP_GE(ssp->srcu_sup->srcu_gp_seq, ssp->srcu_sup->srcu_gp_seq_needed)) {
 		if (!WARN_ON_ONCE(rcu_seq_state(ssp->srcu_sup->srcu_gp_seq))) {
 			/* All requests fulfilled, time to go idle. */
@@ -1975,7 +1951,7 @@ static void srcu_reschedule(struct srcu_struct *ssp, unsigned long delay)
 		/* Outstanding request and no GP.  Start one. */
 		srcu_gp_start(ssp);
 	}
-	spin_unlock_irq_rcu_node(ssp->srcu_sup);
+	raw_spin_unlock_irq_rcu_node(ssp->srcu_sup);
 
 	if (pushgp)
 		queue_delayed_work(rcu_gp_wq, &ssp->srcu_sup->work, delay);
@@ -1995,9 +1971,9 @@ static void process_srcu(struct work_struct *work)
 	ssp = sup->srcu_ssp;
 
 	srcu_advance_state(ssp);
-	spin_lock_irq_rcu_node(ssp->srcu_sup);
+	raw_spin_lock_irq_rcu_node(ssp->srcu_sup);
 	curdelay = srcu_get_delay(ssp);
-	spin_unlock_irq_rcu_node(ssp->srcu_sup);
+	raw_spin_unlock_irq_rcu_node(ssp->srcu_sup);
 	if (curdelay) {
 		WRITE_ONCE(sup->reschedule_count, 0);
 	} else {
@@ -2015,6 +1991,23 @@ static void process_srcu(struct work_struct *work)
 	srcu_reschedule(ssp, curdelay);
 }
 
+static void srcu_irq_work(struct irq_work *work)
+{
+	struct srcu_struct *ssp;
+	struct srcu_usage *sup;
+	unsigned long delay;
+	unsigned long flags;
+
+	sup = container_of(work, struct srcu_usage, irq_work);
+	ssp = sup->srcu_ssp;
+
+	raw_spin_lock_irqsave_rcu_node(ssp->srcu_sup, flags);
+	delay = srcu_get_delay(ssp);
+	raw_spin_unlock_irqrestore_rcu_node(ssp->srcu_sup, flags);
+
+	queue_delayed_work(rcu_gp_wq, &sup->work, !!delay);
+}
+
 void srcutorture_get_gp_data(struct srcu_struct *ssp, int *flags,
 			     unsigned long *gp_seq)
 {