Merge tag 'amd-pstate-v7.3-2026-07-22' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/superm1/linux

Merge amd-pstate content for 7.3 (07/22/26) from Mario Limonciello:

"* Avoid running unit tests without amd-pstate
 * Fixes for EPP on shared memory systems
 * Fixes for dynamic EPP callbacks
 * Avoid loading on guests
 * Allow lowest nonlinear == minimum freq"

* tag 'amd-pstate-v7.3-2026-07-22' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/superm1/linux: (923 commits)
  cpufreq/amd-pstate: handle missing policy in dynamic EPP callbacks
  cpufreq/amd-pstate: Cache the firmware programmed EPP value
  cpufreq/amd-pstate: Toggle auto_sel in active mode on shared memory systems
  cpufreq/amd-pstate: Fix EPP return type and handle errors during initialization
  cpufreq: amd-pstate-ut: Skip tests when amd-pstate driver is not active
  cpufreq/amd-pstate: Prevent the driver from loading on unsupported hardware
  cpufreq/amd-pstate: Loosen requirement on lowest nonlinear frequency != min freq
  Linux 7.2-rc4
  Revert "drm/amd/display: Restore 5s vbl offdelay for NV3x+ DGPUs"
  drm/amd/display: check GRPH_FLIP status before sending event
  drm/amd/display: consolidate DCN vblank/flip handling onto vupdate_no_lock
  drm/amd: Create a device link between APU display and XHCI devices
  drm/amd/display: wire DCN42B mcache programming callback
  drm/amd/display: set new_stream to NULL after release
  drm/amd/display: Force PWM backlight on Lenovo Legion 5 15ARH05
  drm/amdkfd: free MQD managers on DQM init failures
  drm/amdgpu/ttm: Consider concurrent VM flushes for buffer entities
  drm/amd/pm/smu7: Fix AC/DC switch notification
  drm/amdgpu: Disable PCIe dynamic speed switching on Ryzen Pinnacle Ridge
  drm/amdgpu: always emit the job vm fence
  ...

19 files changed, 454 insertions, 192 deletions

diff --git a/kernel/audit.c b/kernel/audit.c
index dcc657d35776..562476937fa7 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -62,6 +62,7 @@
 #include <net/ip.h>
 #include <net/ipv6.h>
 #include <linux/sctp.h>
+#include <linux/overflow.h>
 
 #include "audit.h"
 
@@ -950,7 +951,7 @@ main_queue:
 		 *       do the multicast send and rotate records from the
 		 *       main queue to the retry/hold queues */
 		wait_event_freezable(kauditd_wait,
-				     (skb_queue_len(&audit_queue) ? 1 : 0));
+				(skb_queue_len_lockless(&audit_queue) ? 1 : 0));
 	}
 
 	return 0;
@@ -1283,7 +1284,7 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
 		s.rate_limit		   = audit_rate_limit;
 		s.backlog_limit		   = audit_backlog_limit;
 		s.lost			   = atomic_read(&audit_lost);
-		s.backlog		   = skb_queue_len(&audit_queue);
+		s.backlog		   = skb_queue_len_lockless(&audit_queue);
 		s.feature_bitmap	   = AUDIT_FEATURE_BITMAP_ALL;
 		s.backlog_wait_time	   = audit_backlog_wait_time;
 		s.backlog_wait_time_actual = atomic_read(&audit_backlog_wait_time_actual);
@@ -1627,7 +1628,7 @@ static void audit_receive(struct sk_buff *skb)
 
 	/* can't block with the ctrl lock, so penalize the sender now */
 	if (audit_backlog_limit &&
-	    (skb_queue_len(&audit_queue) > audit_backlog_limit)) {
+	    (skb_queue_len_lockless(&audit_queue) > audit_backlog_limit)) {
 		DECLARE_WAITQUEUE(wait, current);
 
 		/* wake kauditd to try and flush the queue */
@@ -1933,7 +1934,7 @@ struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask,
 		long stime = audit_backlog_wait_time;
 
 		while (audit_backlog_limit &&
-		       (skb_queue_len(&audit_queue) > audit_backlog_limit)) {
+			(skb_queue_len_lockless(&audit_queue) > audit_backlog_limit)) {
 			/* wake kauditd to try and flush the queue */
 			wake_up_interruptible(&kauditd_wait);
 
@@ -1953,7 +1954,7 @@ struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask,
 			} else {
 				if (audit_rate_check() && printk_ratelimit())
 					pr_warn("audit_backlog=%d > audit_backlog_limit=%d\n",
-						skb_queue_len(&audit_queue),
+						skb_queue_len_lockless(&audit_queue),
 						audit_backlog_limit);
 				audit_log_lost("backlog limit exceeded");
 				return NULL;
@@ -2080,7 +2081,8 @@ void audit_log_format(struct audit_buffer *ab, const char *fmt, ...)
 void audit_log_n_hex(struct audit_buffer *ab, const unsigned char *buf,
 		size_t len)
 {
-	int i, avail, new_len;
+	int avail;
+	size_t i, new_len;
 	unsigned char *ptr;
 	struct sk_buff *skb;
 
@@ -2090,7 +2092,12 @@ void audit_log_n_hex(struct audit_buffer *ab, const unsigned char *buf,
 	BUG_ON(!ab->skb);
 	skb = ab->skb;
 	avail = skb_tailroom(skb);
-	new_len = len<<1;
+
+	if (check_shl_overflow(len, 1, &new_len)) {
+		audit_log_format(ab, "?");
+		return;
+	}
+
 	if (new_len >= avail) {
 		/* Round the buffer request up to the next multiple */
 		new_len = AUDIT_BUFSIZ*(((new_len-avail)/AUDIT_BUFSIZ) + 1);
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index 64572f85edc8..c4673a54c4ba 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -9114,6 +9114,35 @@ u32 *btf_kfunc_flags(const struct btf *btf, u32 kfunc_btf_id, const struct bpf_p
 	return btf_kfunc_id_set_contains(btf, hook, kfunc_btf_id);
 }
 
+/*
+ * Check a single KF_* @flag on a kfunc across all of its hook sets.
+ * Returns:
+ *   * 1 if @flag is set
+ *   * 0 if @flag is not set
+ *   * -EINVAL if @flag is set inconsistently across the sets
+ *   * -ENOENT if kfunc_btf_id is not a registered kfunc
+ */
+int btf_kfunc_check_flag(const struct btf *btf, u32 kfunc_btf_id, u32 flag)
+{
+	enum btf_kfunc_hook hook;
+	int res = -ENOENT;
+	bool is_set;
+	u32 *flags;
+
+	for (hook = 0; hook < BTF_KFUNC_HOOK_MAX; hook++) {
+		flags = btf_kfunc_id_set_contains(btf, hook, kfunc_btf_id);
+		if (!flags)
+			continue;
+		is_set = *flags & flag;
+		if (res < 0)
+			res = is_set;
+		else if (res != is_set)
+			return -EINVAL;
+	}
+
+	return res;
+}
+
 u32 *btf_kfunc_is_modify_return(const struct btf *btf, u32 kfunc_btf_id,
 				const struct bpf_prog *prog)
 {
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 6515d4d3c003..99444eae917e 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -2584,24 +2584,25 @@ static struct btf *find_kfunc_desc_btf(struct bpf_verifier_env *env, s16 offset)
 
 #define KF_IMPL_SUFFIX "_impl"
 
-static const struct btf_type *find_kfunc_impl_proto(struct bpf_verifier_env *env,
+static const struct btf_type *find_kfunc_impl_proto(struct bpf_verifier_log *log,
 						    struct btf *btf,
 						    const char *func_name)
 {
-	char *buf = env->tmp_str_buf;
 	const struct btf_type *func;
+	char buf[KSYM_NAME_LEN];
 	s32 impl_id;
 	int len;
 
-	len = snprintf(buf, TMP_STR_BUF_LEN, "%s%s", func_name, KF_IMPL_SUFFIX);
-	if (len < 0 || len >= TMP_STR_BUF_LEN) {
-		verbose(env, "function name %s%s is too long\n", func_name, KF_IMPL_SUFFIX);
+	len = snprintf(buf, sizeof(buf), "%s%s", func_name, KF_IMPL_SUFFIX);
+	if (len < 0 || len >= sizeof(buf)) {
+		bpf_log(log, "function name %s%s is too long\n",
+			func_name, KF_IMPL_SUFFIX);
 		return NULL;
 	}
 
 	impl_id = btf_find_by_name_kind(btf, buf, BTF_KIND_FUNC);
 	if (impl_id <= 0) {
-		verbose(env, "cannot find function %s in BTF\n", buf);
+		bpf_log(log, "cannot find function %s in BTF\n", buf);
 		return NULL;
 	}
 
@@ -2653,7 +2654,7 @@ static int fetch_kfunc_meta(struct bpf_verifier_env *env,
 	 * can be found through the counterpart _impl kfunc.
 	 */
 	if (kfunc_flags && (*kfunc_flags & KF_IMPLICIT_ARGS))
-		func_proto = find_kfunc_impl_proto(env, btf, func_name);
+		func_proto = find_kfunc_impl_proto(&env->log, btf, func_name);
 	else
 		func_proto = btf_type_by_id(btf, func->type);
 
@@ -5326,14 +5327,11 @@ static int check_max_stack_depth(struct bpf_verifier_env *env)
 static int __check_buffer_access(struct bpf_verifier_env *env,
 				 const char *buf_info,
 				 const struct bpf_reg_state *reg,
-				 argno_t argno, int off, int size)
+				 argno_t argno, int off, int size,
+				 u32 *access_end)
 {
-	if (off < 0) {
-		verbose(env,
-			"%s invalid %s buffer access: off=%d, size=%d\n",
-			reg_arg_name(env, argno), buf_info, off, size);
-		return -EACCES;
-	}
+	s64 start;
+
 	if (!tnum_is_const(reg->var_off)) {
 		char tn_buf[48];
 
@@ -5344,6 +5342,15 @@ static int __check_buffer_access(struct bpf_verifier_env *env,
 		return -EACCES;
 	}
 
+	start = (s64)reg->var_off.value + off;
+	if (start < 0) {
+		verbose(env,
+			"%s invalid negative %s buffer offset: off=%d, var_off=%lld\n",
+			reg_arg_name(env, argno), buf_info, off, (s64)reg->var_off.value);
+		return -EACCES;
+	}
+
+	*access_end = start + size;
 	return 0;
 }
 
@@ -5351,14 +5358,14 @@ static int check_tp_buffer_access(struct bpf_verifier_env *env,
 				  const struct bpf_reg_state *reg,
 				  argno_t argno, int off, int size)
 {
+	u32 access_end;
 	int err;
 
-	err = __check_buffer_access(env, "tracepoint", reg, argno, off, size);
+	err = __check_buffer_access(env, "tracepoint", reg, argno, off, size, &access_end);
 	if (err)
 		return err;
 
-	env->prog->aux->max_tp_access = max(reg->var_off.value + off + size,
-					    env->prog->aux->max_tp_access);
+	env->prog->aux->max_tp_access = max(access_end, env->prog->aux->max_tp_access);
 
 	return 0;
 }
@@ -5370,13 +5377,14 @@ static int check_buffer_access(struct bpf_verifier_env *env,
 			       u32 *max_access)
 {
 	const char *buf_info = type_is_rdonly_mem(reg->type) ? "rdonly" : "rdwr";
+	u32 access_end;
 	int err;
 
-	err = __check_buffer_access(env, buf_info, reg, argno, off, size);
+	err = __check_buffer_access(env, buf_info, reg, argno, off, size, &access_end);
 	if (err)
 		return err;
 
-	*max_access = max(reg->var_off.value + off + size, *max_access);
+	*max_access = max(access_end, *max_access);
 
 	return 0;
 }
@@ -18873,6 +18881,47 @@ static int btf_id_allow_sleepable(u32 btf_id, unsigned long addr, const struct b
 	return -EINVAL;
 }
 
+/*
+ * Resolve the prototype describing a trace target's real ABI. A
+ * KF_IMPLICIT_ARGS kfunc has its injected args stripped from the public
+ * prototype, so use the _impl prototype; other targets use their own.
+ */
+static const struct btf_type *
+btf_attach_func_proto(struct bpf_verifier_log *log, struct btf *btf, u32 func_id)
+{
+	const struct btf_type *func;
+	struct module *mod = NULL;
+	const char *name;
+	int implicit;
+
+	func = btf_type_by_id(btf, func_id);
+	if (!func || !btf_type_is_func(func))
+		return NULL;
+	name = btf_name_by_offset(btf, func->name_off);
+
+	/*
+	 * btf_kfunc_check_flag() reads kfunc_set_tab, which for a module is
+	 * stable only once it is live; hold a module ref across the read to
+	 * exclude a concurrent module load.
+	 */
+	if (btf_is_module(btf)) {
+		mod = btf_try_get_module(btf);
+		if (!mod)
+			return NULL;
+	}
+	implicit = btf_kfunc_check_flag(btf, func_id, KF_IMPLICIT_ARGS);
+	module_put(mod);
+
+	if (implicit == -EINVAL) {
+		bpf_log(log, "kfunc %s has inconsistent KF_IMPLICIT_ARGS\n", name);
+		return NULL;
+	}
+	if (implicit > 0)
+		return find_kfunc_impl_proto(log, btf, name);
+
+	return btf_type_by_id(btf, func->type);
+}
+
 int bpf_check_attach_target(struct bpf_verifier_log *log,
 			    const struct bpf_prog *prog,
 			    const struct bpf_prog *tgt_prog,
@@ -19121,8 +19170,8 @@ int bpf_check_attach_target(struct bpf_verifier_log *log,
 		if (prog_extension &&
 		    btf_check_type_match(log, prog, btf, t))
 			return -EINVAL;
-		t = btf_type_by_id(btf, t->type);
-		if (!btf_type_is_func_proto(t))
+		t = btf_attach_func_proto(log, btf, btf_id);
+		if (!t || !btf_type_is_func_proto(t))
 			return -EINVAL;
 
 		if ((prog->aux->saved_dst_prog_type || prog->aux->saved_dst_attach_type) &&
@@ -19405,10 +19454,8 @@ int bpf_check_attach_btf_id_multi(struct btf *btf, struct bpf_prog *prog, u32 bt
 	tname = btf_name_by_offset(btf, t->name_off);
 	if (!tname)
 		return -EINVAL;
-	if (!btf_type_is_func(t))
-		return -EINVAL;
-	t = btf_type_by_id(btf, t->type);
-	if (!btf_type_is_func_proto(t))
+	t = btf_attach_func_proto(NULL, btf, btf_id);
+	if (!t || !btf_type_is_func_proto(t))
 		return -EINVAL;
 	err = btf_distill_func_proto(NULL, btf, t, tname, &tgt_info->fmodel);
 	if (err < 0)
diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
index 591e3aa487fc..45944b3e31ca 100644
--- a/kernel/cgroup/cpuset.c
+++ b/kernel/cgroup/cpuset.c
@@ -2653,7 +2653,12 @@ void cpuset_update_tasks_nodemask(struct cpuset *cs)
 
 		migrate = is_memory_migrate(cs);
 
-		mpol_rebind_mm(mm, &cs->mems_allowed);
+		/*
+		 * For v1 we can have empty effective_mems, but we cannot
+		 * attach any tasks (see cpuset_can_attach_check()). For v2,
+		 * effective_mems is guaranteed to not be empty.
+		 */
+		mpol_rebind_mm(mm, &cs->effective_mems);
 		if (migrate)
 			cpuset_migrate_mm(mm, &cs->old_mems_allowed, &newmems);
 		else
diff --git a/kernel/events/core.c b/kernel/events/core.c
index d7f3e2c2ecb1..ba5bd6a78fe7 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -7150,6 +7150,8 @@ static int map_range(struct perf_buffer *rb, struct vm_area_struct *vma)
 	int err = 0;
 	unsigned long pagenum;
 
+	guard(mutex)(&rb->aux_mutex);
+
 	/*
 	 * We map this as a VM_PFNMAP VMA.
 	 *
diff --git a/kernel/exit.c b/kernel/exit.c
index 1056422bc101..2c0b1c02920f 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -212,7 +212,12 @@ static void __exit_signal(struct release_task_post *post, struct task_struct *ts
 	__unhash_process(post, tsk, group_dead);
 	write_sequnlock(&sig->stats_lock);
 
-	tsk->sighand = NULL;
+	/*
+	 * Ensure that all preceeding state is visible. Pairs with
+	 * the smp_acquire__after_ctrl_dep() in the sighand == NULL
+	 * path of lock_task_sighand().
+	 */
+	smp_store_release(&tsk->sighand, NULL);
 	spin_unlock(&sighand->siglock);
 
 	__cleanup_sighand(sighand);
diff --git a/kernel/sched/ext/ext.c b/kernel/sched/ext/ext.c
index 691d53fe0f64..e3fa7b2fac9d 100644
--- a/kernel/sched/ext/ext.c
+++ b/kernel/sched/ext/ext.c
@@ -479,6 +479,18 @@ static bool rq_is_open(struct rq *rq, u64 enq_flags)
  */
 DEFINE_PER_CPU(struct rq *, scx_locked_rq_state);
 
+static void switch_rq_lock(struct rq *from, struct rq *to)
+{
+	bool tracked = scx_locked_rq() == from;
+
+	if (tracked)
+		update_locked_rq(NULL);
+	raw_spin_rq_unlock(from);
+	raw_spin_rq_lock(to);
+	if (tracked)
+		update_locked_rq(to);
+}
+
 /*
  * Flipped on enable per sch->is_cid_type. Declared in internal.h so
  * subsystem inlines can read it.
@@ -2274,8 +2286,7 @@ static void move_remote_task_to_local_dsq(struct task_struct *p, u64 enq_flags,
 	deactivate_task(src_rq, p, 0);
 	set_task_cpu(p, cpu_of(dst_rq));
 
-	raw_spin_rq_unlock(src_rq);
-	raw_spin_rq_lock(dst_rq);
+	switch_rq_lock(src_rq, dst_rq);
 
 	/*
 	 * We want to pass scx-specific enq_flags but activate_task() will
@@ -2307,6 +2318,7 @@ static void move_remote_task_to_local_dsq(struct task_struct *p, u64 enq_flags,
  *   no to the BPF scheduler initiated migrations while offline.
  *
  * The caller must ensure that @p and @rq are on different CPUs.
+ * If enforce == true, caller must hold @p's rq lock.
  */
 static bool task_can_run_on_remote_rq(struct scx_sched *sch,
 				      struct task_struct *p, struct rq *rq,
@@ -2314,6 +2326,14 @@ static bool task_can_run_on_remote_rq(struct scx_sched *sch,
 {
 	s32 cpu = cpu_of(rq);
 
+	/*
+	 * To prevent races with @p still running on its old CPU while switching
+	 * out, make sure we're holding @p's rq lock so as not to risk
+	 * erroneously killing the BPF scheduler.
+	 */
+	if (enforce)
+		lockdep_assert_rq_held(task_rq(p));
+
 	WARN_ON_ONCE(task_cpu(p) == cpu);
 
 	/*
@@ -2581,13 +2601,6 @@ static void dispatch_to_local_dsq(struct scx_sched *sch, struct rq *rq,
 		return;
 	}
 
-	if (src_rq != dst_rq &&
-	    unlikely(!task_can_run_on_remote_rq(sch, p, dst_rq, true))) {
-		dispatch_enqueue(sch, rq, find_global_dsq(sch, task_cpu(p)), p,
-				 enq_flags | SCX_ENQ_CLEAR_OPSS | SCX_ENQ_GDSQ_FALLBACK);
-		return;
-	}
-
 	/*
 	 * @p is on a possibly remote @src_rq which we need to lock to move the
 	 * task. If dequeue is in progress, it'd be locking @src_rq and waiting
@@ -2606,14 +2619,14 @@ static void dispatch_to_local_dsq(struct scx_sched *sch, struct rq *rq,
 
 	/* switch to @src_rq lock */
 	if (locked_rq != src_rq) {
-		raw_spin_rq_unlock(locked_rq);
+		switch_rq_lock(locked_rq, src_rq);
 		locked_rq = src_rq;
-		raw_spin_rq_lock(src_rq);
 	}
 
 	/* task_rq couldn't have changed if we're still the holding cpu */
 	if (likely(p->scx.holding_cpu == raw_smp_processor_id()) &&
 	    !WARN_ON_ONCE(src_rq != task_rq(p))) {
+		bool fallback = false;
 		/*
 		 * If @p is staying on the same rq, there's no need to go
 		 * through the full deactivate/activate cycle. Optimize by
@@ -2623,6 +2636,11 @@ static void dispatch_to_local_dsq(struct scx_sched *sch, struct rq *rq,
 			p->scx.holding_cpu = -1;
 			dispatch_enqueue(sch, dst_rq, &dst_rq->scx.local_dsq, p,
 					 enq_flags);
+		} else if (unlikely(!task_can_run_on_remote_rq(sch, p, dst_rq, true))) {
+			p->scx.holding_cpu = -1;
+			fallback = true;
+			dispatch_enqueue(sch, src_rq, find_global_dsq(sch, task_cpu(p)),
+					 p, enq_flags | SCX_ENQ_GDSQ_FALLBACK);
 		} else {
 			move_remote_task_to_local_dsq(p, enq_flags,
 						      src_rq, dst_rq);
@@ -2631,15 +2649,13 @@ static void dispatch_to_local_dsq(struct scx_sched *sch, struct rq *rq,
 		}
 
 		/* if the destination CPU is idle, wake it up */
-		if (sched_class_above(p->sched_class, dst_rq->curr->sched_class))
+		if (!fallback && sched_class_above(p->sched_class, dst_rq->curr->sched_class))
 			resched_curr(dst_rq);
 	}
 
 	/* switch back to @rq lock */
-	if (locked_rq != rq) {
-		raw_spin_rq_unlock(locked_rq);
-		raw_spin_rq_lock(rq);
-	}
+	if (locked_rq != rq)
+		switch_rq_lock(locked_rq, rq);
 }
 
 /**
@@ -2970,24 +2986,38 @@ static void set_next_task_scx(struct rq *rq, struct task_struct *p, bool first)
 
 	/*
 	 * @p is getting newly scheduled or got kicked after someone updated its
-	 * slice. Refresh whether tick can be stopped. See scx_can_stop_tick().
+	 * slice. Update SCX_RQ_CAN_STOP_TICK to reflect whether the tick can be
+	 * stopped. See scx_can_stop_tick().
+	 *
+	 * Moreover, refresh the load_avgs just when transitioning in and out of
+	 * nohz. In the future, we might want to add a mechanism to update
+	 * load_avgs periodically on tick-stopped CPUs.
 	 */
-	if ((p->scx.slice == SCX_SLICE_INF) !=
-	    (bool)(rq->scx.flags & SCX_RQ_CAN_STOP_TICK)) {
-		if (p->scx.slice == SCX_SLICE_INF)
+	if (p->scx.slice == SCX_SLICE_INF) {
+		if (!(rq->scx.flags & SCX_RQ_CAN_STOP_TICK)) {
+			/*
+			 * Bypass mode always assigns finite slices, so @p
+			 * can't have an infinite slice while bypassing.
+			 * Therefore, sched_update_tick_dependency() can safely
+			 * evaluate the outgoing task.
+			 */
 			rq->scx.flags |= SCX_RQ_CAN_STOP_TICK;
-		else
-			rq->scx.flags &= ~SCX_RQ_CAN_STOP_TICK;
+			sched_update_tick_dependency(rq);
 
-		sched_update_tick_dependency(rq);
+			update_other_load_avgs(rq);
+		}
+	} else {
+		if (rq->scx.flags & SCX_RQ_CAN_STOP_TICK) {
+			rq->scx.flags &= ~SCX_RQ_CAN_STOP_TICK;
+			update_other_load_avgs(rq);
+		}
 
 		/*
-		 * For now, let's refresh the load_avgs just when transitioning
-		 * in and out of nohz. In the future, we might want to add a
-		 * mechanism which calls the following periodically on
-		 * tick-stopped CPUs.
+		 * @rq still references the outgoing scheduling context. A finite
+		 * slice is sufficient by itself to require the tick.
 		 */
-		update_other_load_avgs(rq);
+		if (tick_nohz_full_cpu(cpu_of(rq)))
+			tick_nohz_dep_set_cpu(cpu_of(rq), TICK_DEP_BIT_SCHED);
 	}
 }
 
@@ -3082,9 +3112,14 @@ static void put_prev_task_scx(struct rq *rq, struct task_struct *p,
 		 * sched_class, %SCX_OPS_ENQ_LAST must be set. Tell
 		 * ops.enqueue() that @p is the only one available for this cpu,
 		 * which should trigger an explicit follow-up scheduling event.
+		 *
+		 * Core scheduling can force this CPU idle while @p stays
+		 * runnable. @p's cookie then won't match the core's, so skip
+		 * the warning in that case.
 		 */
 		if (next && sched_class_above(&ext_sched_class, next->sched_class)) {
-			WARN_ON_ONCE(!(sch->ops.flags & SCX_OPS_ENQ_LAST));
+			WARN_ON_ONCE(sched_cpu_cookie_match(rq, p) &&
+				     !(sch->ops.flags & SCX_OPS_ENQ_LAST));
 			do_enqueue_task(rq, p, SCX_ENQ_LAST, -1);
 		} else {
 			do_enqueue_task(rq, p, 0, -1);
@@ -3648,6 +3683,13 @@ static void scx_disable_task(struct scx_sched *sch, struct task_struct *p)
 	scx_set_task_state(p, SCX_TASK_READY);
 
 	/*
+	 * Reset the SCX-managed fields when @p leaves the BPF scheduler's
+	 * control, after ops.disable() has observed their final values.
+	 */
+	p->scx.dsq_vtime = 0;
+	p->scx.slice = 0;
+
+	/*
 	 * Verify the task is not in BPF scheduler's custody. If flag
 	 * transitions are consistent, the flag should always be clear
 	 * here.
@@ -3925,6 +3967,17 @@ static void reweight_task_scx(struct rq *rq, struct task_struct *p,
 	if (task_dead_and_done(p))
 		return;
 
+	/*
+	 * When switching sched_class away from SCX, reweight_task_scx()
+	 * is called _after_ scx_disable_task(). Skip calling ops.set_weight()
+	 * since the BPF scheduler may have already forgotten the task in
+	 * ops.disable().
+	 * p->scx.weight will be recalculated in scx_enable_task() if the task
+	 * ever returns to SCX class.
+	 */
+	if (scx_get_task_state(p) != SCX_TASK_ENABLED)
+		return;
+
 	p->scx.weight = sched_weight_to_cgroup(scale_load_down(lw->weight));
 	if (SCX_HAS_OP(sch, set_weight))
 		SCX_CALL_OP_TASK(sch, set_weight, rq, p, p->scx.weight);
@@ -4301,6 +4354,15 @@ bool scx_can_stop_tick(struct rq *rq)
 	if (p->sched_class != &ext_sched_class)
 		return true;
 
+	/*
+	 * @rq->curr may still reference an outgoing EXT task after it has been
+	 * dequeued. If no EXT tasks are accounted on @rq, ignore its stale
+	 * slice state. If another task is dispatched from a DSQ,
+	 * set_next_task_scx() will update the dependency for the incoming task.
+	 */
+	if (!rq->scx.nr_running)
+		return true;
+
 	if (scx_bypassing(sch, cpu_of(rq)))
 		return false;
 
@@ -4901,6 +4963,8 @@ static void scx_sched_free_rcu_work(struct work_struct *work)
 		cgroup_put(sch_cgroup(sch));
 	if (sch->sub_kset)
 		kobject_put(&sch->sub_kset->kobj);
+	if (scx_parent(sch))
+		kobject_put(&scx_parent(sch)->kobj);
 #endif	/* CONFIG_EXT_SUB_SCHED */
 
 	for_each_possible_cpu(cpu) {
@@ -5672,7 +5736,7 @@ static void free_kick_syncs(void)
 	int cpu;
 
 	for_each_possible_cpu(cpu) {
-		struct scx_kick_syncs **ksyncs = per_cpu_ptr(&scx_kick_syncs, cpu);
+		struct scx_kick_syncs __rcu **ksyncs = per_cpu_ptr(&scx_kick_syncs, cpu);
 		struct scx_kick_syncs *to_free;
 
 		to_free = rcu_replace_pointer(*ksyncs, NULL, true);
@@ -6653,7 +6717,7 @@ static int alloc_kick_syncs(void)
 	 * can exceed percpu allocator limits on large machines.
 	 */
 	for_each_possible_cpu(cpu) {
-		struct scx_kick_syncs **ksyncs = per_cpu_ptr(&scx_kick_syncs, cpu);
+		struct scx_kick_syncs __rcu **ksyncs = per_cpu_ptr(&scx_kick_syncs, cpu);
 		struct scx_kick_syncs *new_ksyncs;
 
 		WARN_ON_ONCE(rcu_access_pointer(*ksyncs));
@@ -6825,11 +6889,6 @@ static struct scx_sched *scx_alloc_and_add_sched(struct scx_enable_cmd *cmd,
 		sch->ops = *cmd->ops;
 	}
 
-	rcu_assign_pointer(ops->priv, sch);
-
-	sch->kobj.kset = scx_kset;
-	INIT_LIST_HEAD(&sch->all);
-
 #ifdef CONFIG_EXT_SUB_SCHED
 	char *buf = kzalloc(PATH_MAX, GFP_KERNEL);
 	if (!buf) {
@@ -6847,13 +6906,32 @@ static struct scx_sched *scx_alloc_and_add_sched(struct scx_enable_cmd *cmd,
 	sch->cgrp = cgrp;
 	INIT_LIST_HEAD(&sch->children);
 	INIT_LIST_HEAD(&sch->sibling);
+#endif	/* CONFIG_EXT_SUB_SCHED */
 
-	if (parent)
+	/*
+	 * Publishing makes @sch visible to scx_prog_sched() readers. Failure
+	 * paths after this point must free @sch through kobject_put() whose
+	 * release path defers the actual freeing by an RCU grace period.
+	 */
+	rcu_assign_pointer(ops->priv, sch);
+
+	sch->kobj.kset = scx_kset;
+	INIT_LIST_HEAD(&sch->all);
+
+#ifdef CONFIG_EXT_SUB_SCHED
+	if (parent) {
+		/*
+		 * Pin @parent for @sch's lifetime. The kobject hierarchy pins
+		 * it only via @parent->sub_kset, which is dropped during
+		 * disable. Released in scx_sched_free_rcu_work().
+		 */
+		kobject_get(&parent->kobj);
 		ret = kobject_init_and_add(&sch->kobj, &scx_ktype,
 					   &parent->sub_kset->kobj,
 					   "sub-%llu", cgroup_id(cgrp));
-	else
+	} else {
 		ret = kobject_init_and_add(&sch->kobj, &scx_ktype, NULL, "root");
+	}
 
 	if (ret < 0) {
 		RCU_INIT_POINTER(ops->priv, NULL);
@@ -6895,7 +6973,6 @@ static struct scx_sched *scx_alloc_and_add_sched(struct scx_enable_cmd *cmd,
 
 #ifdef CONFIG_EXT_SUB_SCHED
 err_free_lb_resched:
-	RCU_INIT_POINTER(ops->priv, NULL);
 	free_cpumask_var(sch->bypass_lb_resched_cpumask);
 #endif
 err_free_lb_cpumask:
@@ -6988,7 +7065,7 @@ static int validate_ops(struct scx_sched *sch, const struct sched_ext_ops *ops)
 	 * run past the BPF allocation. Skip for cid-form.
 	 */
 	if (!sch->is_cid_type && (ops->cpu_acquire || ops->cpu_release))
-		pr_warn("ops->cpu_acquire/release() are deprecated, use sched_switch TP instead\n");
+		pr_warn_ratelimited("ops->cpu_acquire/release() are deprecated, use sched_switch TP instead\n");
 
 	/*
 	 * Sub-scheduler support is tied to the cid-form struct_ops. A sub-sched
@@ -7686,6 +7763,12 @@ err_unlock_and_disable:
 	percpu_up_write(&scx_fork_rwsem);
 err_disable:
 	mutex_unlock(&scx_enable_mutex);
+	/*
+	 * Some enable failures only return an errno (e.g. -ENOMEM from an
+	 * allocation) without calling scx_error(). Record it so
+	 * scx_flush_disable_work() runs the disable and ops.exit() fires.
+	 */
+	scx_error(sch, "scx_sub_enable() failed (%d)", ret);
 	scx_flush_disable_work(sch);
 	cmd->ret = 0;
 }
@@ -7806,7 +7889,7 @@ static int bpf_scx_btf_struct_access(struct bpf_verifier_log *log,
 		     off + size <= offsetofend(struct task_struct, scx.slice)) ||
 		    (off >= offsetof(struct task_struct, scx.dsq_vtime) &&
 		     off + size <= offsetofend(struct task_struct, scx.dsq_vtime))) {
-			pr_warn("sched_ext: Writing directly to p->scx.slice/dsq_vtime is deprecated, use scx_bpf_task_set_slice/dsq_vtime()");
+			pr_warn_ratelimited("sched_ext: Writing directly to p->scx.slice/dsq_vtime is deprecated, use scx_bpf_task_set_slice/dsq_vtime()\n");
 			return SCALAR_VALUE;
 		}
 
@@ -8796,10 +8879,8 @@ static bool scx_dsq_move(struct bpf_iter_scx_dsq_kern *kit,
 	in_balance = this_rq->scx.flags & SCX_RQ_IN_BALANCE;
 
 	if (in_balance) {
-		if (this_rq != src_rq) {
-			raw_spin_rq_unlock(this_rq);
-			raw_spin_rq_lock(src_rq);
-		}
+		if (this_rq != src_rq)
+			switch_rq_lock(this_rq, src_rq);
 	} else {
 		raw_spin_rq_lock(src_rq);
 	}
@@ -8831,10 +8912,8 @@ static bool scx_dsq_move(struct bpf_iter_scx_dsq_kern *kit,
 	dispatched = true;
 out:
 	if (in_balance) {
-		if (this_rq != locked_rq) {
-			raw_spin_rq_unlock(locked_rq);
-			raw_spin_rq_lock(this_rq);
-		}
+		if (this_rq != locked_rq)
+			switch_rq_lock(locked_rq, this_rq);
 	} else {
 		raw_spin_rq_unlock_irqrestore(locked_rq, flags);
 	}
diff --git a/kernel/sched/ext/internal.h b/kernel/sched/ext/internal.h
index 145272cb4d8a..673059fa9d72 100644
--- a/kernel/sched/ext/internal.h
+++ b/kernel/sched/ext/internal.h
@@ -1469,21 +1469,24 @@ static const char *scx_enable_state_str[] = {
  * The sched_ext core uses a "lock dancing" protocol coordinated by
  * p->scx.holding_cpu. When moving a task to a different rq:
  *
- *   1. Verify task can be moved (CPU affinity, migration_disabled, etc.)
- *   2. Set p->scx.holding_cpu to the current CPU
- *   3. Set task state to %SCX_OPSS_NONE; dequeue waits while DISPATCHING
+ *   1. Set p->scx.holding_cpu to the current CPU
+ *   2. Set task state to %SCX_OPSS_NONE; dequeue waits while DISPATCHING
  *      is set, so clearing DISPATCHING first prevents the circular wait
  *      (safe to lock the rq we need)
- *   4. Unlock the current CPU's rq
- *   5. Lock src_rq (where the task currently lives)
- *   6. Verify p->scx.holding_cpu == current CPU, if not, dequeue won the
+ *   3. Unlock the current CPU's rq
+ *   4. Lock src_rq (where the task currently lives)
+ *   5. Verify p->scx.holding_cpu == current CPU, if not, dequeue won the
  *      race (dequeue clears holding_cpu to -1 when it takes the task), in
  *      this case migration is aborted
- *   7. If src_rq == dst_rq: clear holding_cpu and enqueue directly
+ *   6. If src_rq == dst_rq: clear holding_cpu and enqueue directly
  *      into dst_rq's local DSQ (no lock swap needed)
- *   8. Otherwise: call move_remote_task_to_local_dsq(), which releases
- *      src_rq, locks dst_rq, and performs the deactivate/activate
- *      migration cycle (dst_rq is held on return)
+ *   7. Otherwise, verify under src_rq lock that the task can be moved to dst_rq
+ *      (CPU affinity, migration_disabled, etc.). If not, clear holding_cpu,
+ *      leave the task on src_rq, and enqueue it on the fallback DSQ.
+ *   8. Otherwise (i.e. if the task can be moved to dst_rq), call
+ *      move_remote_task_to_local_dsq(), which releases src_rq, locks dst_rq,
+ *      and performs the deactivate/activate migration cycle
+ *      (dst_rq is held on return)
  *   9. Unlock dst_rq and re-lock the current CPU's rq to restore
  *      the lock state expected by the caller
  *
diff --git a/kernel/signal.c b/kernel/signal.c
index 9c2b32c4d755..bbc0fd4cc4d7 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -1362,8 +1362,16 @@ struct sighand_struct *lock_task_sighand(struct task_struct *tsk,
 	rcu_read_lock();
 	for (;;) {
 		sighand = rcu_dereference(tsk->sighand);
-		if (unlikely(sighand == NULL))
+		if (unlikely(sighand == NULL)) {
+			/*
+			 * Pairs with the smp_store_release() in
+			 * __exit_signal().  It ensures that all state
+			 * modifications to the task preceeding the store are
+			 * visible to the callers of lock_task_sighand().
+			 */
+			smp_acquire__after_ctrl_dep();
 			break;
+		}
 
 		/*
 		 * This sighand can be already freed and even reused, but
diff --git a/kernel/time/posix-cpu-timers.c b/kernel/time/posix-cpu-timers.c
index 5e633d8750d1..a7d3e8229c4b 100644
--- a/kernel/time/posix-cpu-timers.c
+++ b/kernel/time/posix-cpu-timers.c
@@ -461,6 +461,109 @@ static void disarm_timer(struct k_itimer *timer, struct task_struct *p)
 		trigger_base_recalc_expires(timer, p);
 }
 
+/*
+ * Lookup the task via timer->it.cpu.pid and attempt to lock the task's sighand.
+ *
+ * This can race with the reaping of the task:
+ *
+ * CPU0					CPU1
+ *
+ * // Finds task
+ * p = pid_task(pid, pid_type);		__exit_signal(p)
+ *					  lock(p, sighand);
+ *					  posix_cpu_timers*_exit();
+ * sighand = lock_task_sighand(p);	  unhash_task(p);
+ *					  p->sighand = NULL;
+ *					  unlock(sighand);
+ *
+ * In this case sighand is NULL, which means the task and the associated timer
+ * queue cannot be longer accessed safely.
+ *
+ * __exit_signal() invokes posix_cpu_timers_exit() and if the thread group is
+ * dead it also invokes posix_cpu_timers_group_exit(). These functions delete
+ * all pending timers from the related timer queues. The POSIX timers (k_itimer)
+ * themself are still accessible, but not longer connected to the task.
+ *
+ * exec() works slightly differently. The task which exec()'s terminates all
+ * other threads in the thread group and runs __exit_signal() on them. As the
+ * thread group is not dead they only clean up the per task timers via
+ * posix_cpu_timers_exit().
+ *
+ * As the TGID on exec() stays the same per process timers stay queued, if they
+ * are armed. This works without a problem when exec() is done by the thread
+ * group leader. If a non-leader thread exec()'s this can end up in the
+ * following scenario:
+ *
+ * CPU0					CPU1
+ * // Returns old leader
+ * p = pid_task(pid, pid_type);		de_thread()
+ *					switch_leader()
+ *					release_task(old leader)
+ *					  __exit_signal()
+ *					  old_leader->sighand = NULL;
+ * // Returns NULL
+ * sighand = lock_task_sighand(p)
+ *
+ * That's problematic for several functions:
+ *
+ *  - posix_cpu_timer_del(): If the timer is still enqueued on the task the
+ *    underlying k_itimer will be freed which results in a UAF in
+ *    run_posix_cpu_timers() or on timerqueue related add/delete operations.
+ *    If the timer is not enqueued, the failure is harmless
+ *
+ *  - posix_cpu_timer_set(): Independent of the enqueued state that results in a
+ *    transient failure which is user space visible (-ESRCH) for regular posix
+ *    timers. But for the use case in do_cpu_nanosleep() it's the same UAF
+ *    problem just that the timer is allocated on the stack.
+ *
+ *  - posix_cpu_timer_rearm(): Timer is not enqueued at that point, but this
+ *    silently ignores the rearm request, which is a functional problem as the
+ *    timer wont expire anymore.
+ */
+static struct task_struct *timer_lock_sighand(struct k_itimer *timer, unsigned long *flags)
+{
+	enum pid_type type = clock_pid_type(timer->it_clock);
+	struct cpu_timer *ctmr = &timer->it.cpu;
+
+	guard(rcu)();
+
+	for (;;) {
+		struct task_struct *t = pid_task(timer->it.cpu.pid, type);
+
+		/* Fail if the task cannot be found. */
+		if (!t)
+			break;
+
+		/* Try to lock the task's sighand */
+		if (lock_task_sighand(t, flags))
+			return t;
+
+		/*
+		 * The next PID lookup might either fail or return the new
+		 * leader. This is correct for both exit() and exec().
+		 */
+	}
+
+	/*
+	 * If the timer is still enqueued, warn. There is nothing safe to do
+	 * here as there might be two timers in there which are removed in
+	 * parallel and that will cause more damage than good. This should never
+	 * happen!
+	 *
+	 * Ensure that the stores to the timer and timerqueue are visible:
+	 *
+	 * __exit_signal()
+	 *   posix_cpu_timers*_exit()
+	 *   write_seqlock(seqlock)
+	 *	smp_wmb(); <-------
+	 *   __unhash_process()	  |	!pid_task()
+	 *			  ---->	smp_rmb();
+	 *				WARN_ON_ONCE(...)
+	 */
+	smp_rmb();
+	WARN_ON_ONCE(ctmr->head || timerqueue_node_queued(&ctmr->node));
+	return NULL;
+}
 
 /*
  * Clean up a CPU-clock timer that is about to be destroyed.
@@ -470,29 +573,13 @@ static void disarm_timer(struct k_itimer *timer, struct task_struct *p)
  */
 static int posix_cpu_timer_del(struct k_itimer *timer)
 {
-	struct cpu_timer *ctmr = &timer->it.cpu;
-	struct sighand_struct *sighand;
 	struct task_struct *p;
 	unsigned long flags;
 	int ret = 0;
 
-	rcu_read_lock();
-	p = cpu_timer_task_rcu(timer);
-	if (!p)
-		goto out;
+	p = timer_lock_sighand(timer, &flags);
 
-	/*
-	 * Protect against sighand release/switch in exit/exec and process/
-	 * thread timer list entry concurrent read/writes.
-	 */
-	sighand = lock_task_sighand(p, &flags);
-	if (unlikely(sighand == NULL)) {
-		/*
-		 * This raced with the reaping of the task. The exit cleanup
-		 * should have removed this timer from the timer queue.
-		 */
-		WARN_ON_ONCE(ctmr->head || timerqueue_node_queued(&ctmr->node));
-	} else {
+	if (likely(p)) {
 		if (timer->it.cpu.firing) {
 			/*
 			 * Prevent signal delivery. The timer cannot be dequeued
@@ -508,11 +595,8 @@ static int posix_cpu_timer_del(struct k_itimer *timer)
 		unlock_task_sighand(p, &flags);
 	}
 
-out:
-	rcu_read_unlock();
-
 	if (!ret) {
-		put_pid(ctmr->pid);
+		put_pid(timer->it.cpu.pid);
 		timer->it_status = POSIX_TIMER_DISARMED;
 	}
 	return ret;
@@ -626,21 +710,17 @@ static int posix_cpu_timer_set(struct k_itimer *timer, int timer_flags,
 	clockid_t clkid = CPUCLOCK_WHICH(timer->it_clock);
 	struct cpu_timer *ctmr = &timer->it.cpu;
 	u64 old_expires, new_expires, now;
-	struct sighand_struct *sighand;
 	struct task_struct *p;
 	unsigned long flags;
 	int ret = 0;
 
-	rcu_read_lock();
-	p = cpu_timer_task_rcu(timer);
-	if (!p) {
-		/*
-		 * If p has just been reaped, we can no
-		 * longer get any information about it at all.
-		 */
-		rcu_read_unlock();
+	p = timer_lock_sighand(timer, &flags);
+	/*
+	 * If p has just been reaped, we can no longer get any information about
+	 * it at all.
+	 */
+	if (!p)
 		return -ESRCH;
-	}
 
 	/*
 	 * Use the to_ktime conversion because that clamps the maximum
@@ -648,20 +728,6 @@ static int posix_cpu_timer_set(struct k_itimer *timer, int timer_flags,
 	 */
 	new_expires = ktime_to_ns(timespec64_to_ktime(new->it_value));
 
-	/*
-	 * Protect against sighand release/switch in exit/exec and p->cpu_timers
-	 * and p->signal->cpu_timers read/write in arm_timer()
-	 */
-	sighand = lock_task_sighand(p, &flags);
-	/*
-	 * If p has just been reaped, we can no
-	 * longer get any information about it at all.
-	 */
-	if (unlikely(sighand == NULL)) {
-		rcu_read_unlock();
-		return -ESRCH;
-	}
-
 	/* Retrieve the current expiry time before disarming the timer */
 	old_expires = cpu_timer_getexpires(ctmr);
 
@@ -698,7 +764,7 @@ static int posix_cpu_timer_set(struct k_itimer *timer, int timer_flags,
 	/* Retry if the timer expiry is running concurrently */
 	if (unlikely(ret)) {
 		unlock_task_sighand(p, &flags);
-		goto out;
+		return ret;
 	}
 
 	/* Convert relative expiry time to absolute */
@@ -733,8 +799,6 @@ static int posix_cpu_timer_set(struct k_itimer *timer, int timer_flags,
 	 */
 	if (!sigev_none && new_expires && now >= new_expires)
 		cpu_timer_fire(timer);
-out:
-	rcu_read_unlock();
 	return ret;
 }
 
@@ -1018,19 +1082,12 @@ static void check_process_timers(struct task_struct *tsk,
 static bool posix_cpu_timer_rearm(struct k_itimer *timer)
 {
 	clockid_t clkid = CPUCLOCK_WHICH(timer->it_clock);
-	struct sighand_struct *sighand;
 	struct task_struct *p;
 	unsigned long flags;
 	u64 now;
 
-	guard(rcu)();
-	p = cpu_timer_task_rcu(timer);
-	if (!p)
-		return true;
-
-	/* Protect timer list r/w in arm_timer() */
-	sighand = lock_task_sighand(p, &flags);
-	if (unlikely(sighand == NULL))
+	p = timer_lock_sighand(timer, &flags);
+	if (unlikely(!p))
 		return true;
 
 	/*
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 56a328e94395..804ccae694d2 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -270,7 +270,8 @@ unsigned ring_buffer_event_length(struct ring_buffer_event *event)
 	if (event->type_len > RINGBUF_TYPE_DATA_TYPE_LEN_MAX)
 		return length;
 	length -= RB_EVNT_HDR_SIZE;
-	if (length > RB_MAX_SMALL_DATA + sizeof(event->array[0]))
+	if (length > RB_MAX_SMALL_DATA + sizeof(event->array[0]) ||
+	    RB_FORCE_8BYTE_ALIGNMENT)
                 length -= sizeof(event->array[0]);
 	return length;
 }
@@ -2329,10 +2330,7 @@ static struct ring_buffer_desc *ring_buffer_desc(struct trace_buffer_desc *trace
 	size_t len;
 	int i;
 
-	if (!trace_desc)
-		return NULL;
-
-	if (cpu >= trace_desc->nr_cpus)
+	if (!trace_desc || !trace_desc->nr_cpus)
 		return NULL;
 
 	end = (struct ring_buffer_desc *)((void *)trace_desc + trace_desc->struct_len);
@@ -7174,7 +7172,7 @@ int ring_buffer_read_page(struct trace_buffer *buffer,
 			rpos = reader->read;
 			pos += event_size;
 
-			if (rpos >= event_size)
+			if (rpos >= size)
 				break;
 
 			event = rb_reader_event(cpu_buffer);
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 1146b83b711a..18710c190c92 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -87,7 +87,7 @@ void __init disable_tracing_selftest(const char *reason)
 
 /* Pipe tracepoints to printk */
 static struct trace_iterator *tracepoint_print_iter;
-int tracepoint_printk;
+static int tracepoint_printk;
 static bool tracepoint_printk_stop_on_boot __initdata;
 static bool traceoff_after_boot __initdata;
 static DEFINE_STATIC_KEY_FALSE(tracepoint_printk_key);
@@ -5015,7 +5015,6 @@ int tracing_set_tracer(struct trace_array *tr, const char *buf)
 						RING_BUFFER_ALL_CPUS);
 		if (ret < 0)
 			return ret;
-		ret = 0;
 	}
 
 	list_for_each_entry(t, &tr->tracers, list) {
diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c
index 609325f57942..6385cd662d8d 100644
--- a/kernel/trace/trace_events_filter.c
+++ b/kernel/trace/trace_events_filter.c
@@ -1056,11 +1056,9 @@ static int regex_match_end(char *str, struct regex *r, int len)
 	return 0;
 }
 
-static int regex_match_glob(char *str, struct regex *r, int len __maybe_unused)
+static int regex_match_glob(char *str, struct regex *r, int len)
 {
-	if (glob_match(r->pattern, str))
-		return 1;
-	return 0;
+	return glob_match_len(r->pattern, str, len) ? 1 : 0;
 }
 
 /**
diff --git a/kernel/trace/trace_events_synth.c b/kernel/trace/trace_events_synth.c
index e6871230bde9..dc15658a887c 100644
--- a/kernel/trace/trace_events_synth.c
+++ b/kernel/trace/trace_events_synth.c
@@ -839,8 +839,10 @@ static struct synth_field *parse_synth_field(int argc, char **argv,
 			seq_buf_puts(&s, "__data_loc ");
 			seq_buf_puts(&s, field->type);
 
-			if (WARN_ON_ONCE(!seq_buf_buffer_left(&s)))
+			if (WARN_ON_ONCE(!seq_buf_buffer_left(&s))) {
+				kfree(type);
 				goto free;
+			}
 			s.buffer[s.len] = '\0';
 
 			kfree(field->type);
@@ -1446,13 +1448,13 @@ static int __create_synth_event(const char *name, const char *raw_fields)
 			if (cmd_version > 1 && n_fields_this_loop >= 1) {
 				synth_err(SYNTH_ERR_INVALID_CMD, errpos(field_str));
 				ret = -EINVAL;
-				goto err_free_arg;
+				goto err_free_field;
 			}
 
 			if (n_fields == SYNTH_FIELDS_MAX) {
 				synth_err(SYNTH_ERR_TOO_MANY_FIELDS, 0);
 				ret = -EINVAL;
-				goto err_free_arg;
+				goto err_free_field;
 			}
 			fields[n_fields++] = field;
 
@@ -1491,6 +1493,8 @@ static int __create_synth_event(const char *name, const char *raw_fields)
 	kfree(saved_fields);
 
 	return ret;
+ err_free_field:
+	free_synth_field(field);
  err_free_arg:
 	argv_free(argv);
  err:
diff --git a/kernel/trace/trace_events_user.c b/kernel/trace/trace_events_user.c
index c4ba484f7b38..8c82ecb735f4 100644
--- a/kernel/trace/trace_events_user.c
+++ b/kernel/trace/trace_events_user.c
@@ -109,6 +109,9 @@ struct user_event_enabler {
 
 	/* Track enable bit, flags, etc. Aligned for bitops. */
 	unsigned long		values;
+
+	/* Defer the event put and enabler free past an RCU grace period. */
+	struct rcu_work		put_rwork;
 };
 
 /* Bits 0-5 are for the bit to update upon enable/disable (0-63 allowed) */
@@ -396,17 +399,39 @@ error:
 	return NULL;
 };
 
-static void user_event_enabler_destroy(struct user_event_enabler *enabler,
-				       bool locked)
+static void delayed_user_event_enabler_put(struct work_struct *work)
 {
-	list_del_rcu(&enabler->mm_enablers_link);
+	struct user_event_enabler *enabler = container_of(to_rcu_work(work),
+			struct user_event_enabler, put_rwork);
 
 	/* No longer tracking the event via the enabler */
-	user_event_put(enabler->event, locked);
+	user_event_put(enabler->event, false);
 
+	/* Run from queue_rcu_work(), the RCU grace period has elapsed */
 	kfree(enabler);
 }
 
+static void user_event_enabler_destroy(struct user_event_enabler *enabler)
+{
+	list_del_rcu(&enabler->mm_enablers_link);
+
+	/*
+	 * The enabler is removed from an RCU-traversed list
+	 * (user_event_mm_dup() walks mm->enablers under rcu_read_lock() only),
+	 * and readers there dereference enabler->event and take a new ref on
+	 * it. Both the put of that event reference and the free of the enabler
+	 * therefore have to wait for a grace period so no reader can be looking
+	 * at the enabler or racing the last put of its event.
+	 *
+	 * The put itself must not run in RCU context: when it drops the last
+	 * reference user_event_put() takes event_mutex, which cannot be taken
+	 * from a softirq/RCU callback. Defer both to a work item scheduled
+	 * after a grace period via queue_rcu_work().
+	 */
+	INIT_RCU_WORK(&enabler->put_rwork, delayed_user_event_enabler_put);
+	queue_rcu_work(system_percpu_wq, &enabler->put_rwork);
+}
+
 static int user_event_mm_fault_in(struct user_event_mm *mm, unsigned long uaddr,
 				  int attempt)
 {
@@ -464,7 +489,7 @@ static void user_event_enabler_fault_fixup(struct work_struct *work)
 
 	/* User asked for enabler to be removed during fault */
 	if (test_bit(ENABLE_VAL_FREEING_BIT, ENABLE_BITOPS(enabler))) {
-		user_event_enabler_destroy(enabler, true);
+		user_event_enabler_destroy(enabler);
 		goto out;
 	}
 
@@ -764,7 +789,7 @@ static void user_event_mm_destroy(struct user_event_mm *mm)
 	struct user_event_enabler *enabler, *next;
 
 	list_for_each_entry_safe(enabler, next, &mm->enablers, mm_enablers_link)
-		user_event_enabler_destroy(enabler, false);
+		user_event_enabler_destroy(enabler);
 
 	mmdrop(mm->mm);
 	kfree(mm);
@@ -2645,7 +2670,7 @@ static long user_events_ioctl_unreg(unsigned long uarg)
 			flags |= enabler->values & ENABLE_VAL_COMPAT_MASK;
 
 			if (!test_bit(ENABLE_VAL_FAULTING_BIT, ENABLE_BITOPS(enabler)))
-				user_event_enabler_destroy(enabler, true);
+				user_event_enabler_destroy(enabler);
 
 			/* Removed at least one */
 			ret = 0;
diff --git a/kernel/trace/trace_functions.c b/kernel/trace/trace_functions.c
index f283391a4dc8..cd37f2013758 100644
--- a/kernel/trace/trace_functions.c
+++ b/kernel/trace/trace_functions.c
@@ -458,12 +458,12 @@ func_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
 	ftrace_func_t func;
 	u32 new_flags;
 
-	/* Do nothing if already set. */
-	if (!!set == !!(tr->current_trace_flags->val & bit))
+	/* We can change this flag only when current tracer is function. */
+	if (tr->current_trace != &function_trace)
 		return 0;
 
-	/* We can change this flag only when not running. */
-	if (tr->current_trace != &function_trace)
+	/* Do nothing if already set. */
+	if (!!set == !!(tr->current_trace_flags->val & bit))
 		return 0;
 
 	new_flags = (tr->current_trace_flags->val & ~bit) | (set ? bit : 0);
diff --git a/kernel/trace/trace_osnoise.c b/kernel/trace/trace_osnoise.c
index 5e83c4f6f2b4..0e1265acd1cc 100644
--- a/kernel/trace/trace_osnoise.c
+++ b/kernel/trace/trace_osnoise.c
@@ -179,7 +179,9 @@ static void osnoise_unregister_instance(struct trace_array *tr)
 	if (!found)
 		return;
 
-	kvfree_rcu_mightsleep(inst);
+	/* Do a full sync to ensure that tr remains valid, not just inst */
+	synchronize_rcu();
+	kvfree(inst);
 }
 
 /*
diff --git a/kernel/trace/trace_preemptirq.c b/kernel/trace/trace_preemptirq.c
index 0c42b15c3800..b63e3558948f 100644
--- a/kernel/trace/trace_preemptirq.c
+++ b/kernel/trace/trace_preemptirq.c
@@ -30,7 +30,7 @@
 #else
 #define trace(point, args)					\
 	do {							\
-		if (trace_##point##_enabled()) {		\
+		if (__trace_##point##_enabled()) {		\
 			bool exit_rcu = false;			\
 			if (in_nmi())				\
 				break;				\
diff --git a/kernel/trace/trace_remote.c b/kernel/trace/trace_remote.c
index 2a6cc000ec98..0f6ef5c36d84 100644
--- a/kernel/trace/trace_remote.c
+++ b/kernel/trace/trace_remote.c
@@ -979,33 +979,30 @@ EXPORT_SYMBOL_GPL(trace_remote_free_buffer);
 int trace_remote_alloc_buffer(struct trace_buffer_desc *desc, size_t desc_size, size_t buffer_size,
 			      const struct cpumask *cpumask)
 {
+	size_t min_desc_size = trace_buffer_desc_size(buffer_size, cpumask_weight(cpumask));
 	unsigned int nr_pages = max(DIV_ROUND_UP(buffer_size, PAGE_SIZE), 2UL) + 1;
-	void *desc_end = desc + desc_size;
 	struct ring_buffer_desc *rb_desc;
 	int cpu, ret = -ENOMEM;
 
-	if (desc_size < struct_size(desc, __data, 0))
+	if (desc_size < min_desc_size)
 		return -EINVAL;
 
 	desc->nr_cpus = 0;
-	desc->struct_len = struct_size(desc, __data, 0);
+	desc->struct_len = min_desc_size;
 
-	rb_desc = (struct ring_buffer_desc *)&desc->__data[0];
+	rb_desc = __first_ring_buffer_desc(desc);
 
 	for_each_cpu(cpu, cpumask) {
 		unsigned int id;
 
-		if ((void *)rb_desc + struct_size(rb_desc, page_va, nr_pages) > desc_end) {
-			ret = -EINVAL;
-			goto err;
-		}
-
 		rb_desc->cpu = cpu;
 		rb_desc->nr_page_va = 0;
 		rb_desc->meta_va = (unsigned long)__get_free_page(GFP_KERNEL);
 		if (!rb_desc->meta_va)
 			goto err;
 
+		desc->nr_cpus++;
+
 		for (id = 0; id < nr_pages; id++) {
 			rb_desc->page_va[id] = (unsigned long)__get_free_page(GFP_KERNEL);
 			if (!rb_desc->page_va[id])
@@ -1013,9 +1010,6 @@ int trace_remote_alloc_buffer(struct trace_buffer_desc *desc, size_t desc_size,
 
 			rb_desc->nr_page_va++;
 		}
-		desc->nr_cpus++;
-		desc->struct_len += offsetof(struct ring_buffer_desc, page_va);
-		desc->struct_len += struct_size(rb_desc, page_va, rb_desc->nr_page_va);
 		rb_desc = __next_ring_buffer_desc(rb_desc);
 	}