Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

1 files changed, 206 insertions, 0 deletions

diff --git a/include/net/tcx.h b/include/net/tcx.h
new file mode 100644
index 000000000..23a61af13
--- /dev/null
+++ b/include/net/tcx.h
@@ -0,0 +1,206 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright (c) 2023 Isovalent */
+#ifndef __NET_TCX_H
+#define __NET_TCX_H
+
+#include <linux/bpf.h>
+#include <linux/bpf_mprog.h>
+
+#include <net/sch_generic.h>
+
+struct mini_Qdisc;
+
+struct tcx_entry {
+	struct mini_Qdisc __rcu *miniq;
+	struct bpf_mprog_bundle bundle;
+	u32 miniq_active;
+	struct rcu_head rcu;
+};
+
+struct tcx_link {
+	struct bpf_link link;
+	struct net_device *dev;
+};
+
+static inline void tcx_set_ingress(struct sk_buff *skb, bool ingress)
+{
+#ifdef CONFIG_NET_XGRESS
+	skb->tc_at_ingress = ingress;
+#endif
+}
+
+#ifdef CONFIG_NET_XGRESS
+static inline struct tcx_entry *tcx_entry(struct bpf_mprog_entry *entry)
+{
+	struct bpf_mprog_bundle *bundle = entry->parent;
+
+	return container_of(bundle, struct tcx_entry, bundle);
+}
+
+static inline struct tcx_link *tcx_link(const struct bpf_link *link)
+{
+	return container_of(link, struct tcx_link, link);
+}
+
+void tcx_inc(void);
+void tcx_dec(void);
+
+static inline void tcx_entry_sync(void)
+{
+	/* bpf_mprog_entry got a/b swapped, therefore ensure that
+	 * there are no inflight users on the old one anymore.
+	 */
+	synchronize_rcu();
+}
+
+static inline void
+tcx_entry_update(struct net_device *dev, struct bpf_mprog_entry *entry,
+		 bool ingress)
+{
+	ASSERT_RTNL();
+	if (ingress)
+		rcu_assign_pointer(dev->tcx_ingress, entry);
+	else
+		rcu_assign_pointer(dev->tcx_egress, entry);
+}
+
+static inline struct bpf_mprog_entry *
+tcx_entry_fetch(struct net_device *dev, bool ingress)
+{
+	ASSERT_RTNL();
+	if (ingress)
+		return rcu_dereference_rtnl(dev->tcx_ingress);
+	else
+		return rcu_dereference_rtnl(dev->tcx_egress);
+}
+
+static inline struct bpf_mprog_entry *tcx_entry_create_noprof(void)
+{
+	struct tcx_entry *tcx = kzalloc_noprof(sizeof(*tcx), GFP_KERNEL);
+
+	if (tcx) {
+		bpf_mprog_bundle_init(&tcx->bundle);
+		return &tcx->bundle.a;
+	}
+	return NULL;
+}
+#define tcx_entry_create(...)	alloc_hooks(tcx_entry_create_noprof(__VA_ARGS__))
+
+static inline void tcx_entry_free(struct bpf_mprog_entry *entry)
+{
+	kfree_rcu(tcx_entry(entry), rcu);
+}
+
+static inline struct bpf_mprog_entry *
+tcx_entry_fetch_or_create(struct net_device *dev, bool ingress, bool *created)
+{
+	struct bpf_mprog_entry *entry = tcx_entry_fetch(dev, ingress);
+
+	*created = false;
+	if (!entry) {
+		entry = tcx_entry_create();
+		if (!entry)
+			return NULL;
+		*created = true;
+	}
+	return entry;
+}
+
+static inline void tcx_skeys_inc(bool ingress)
+{
+	tcx_inc();
+	if (ingress)
+		net_inc_ingress_queue();
+	else
+		net_inc_egress_queue();
+}
+
+static inline void tcx_skeys_dec(bool ingress)
+{
+	if (ingress)
+		net_dec_ingress_queue();
+	else
+		net_dec_egress_queue();
+	tcx_dec();
+}
+
+static inline void tcx_miniq_inc(struct bpf_mprog_entry *entry)
+{
+	ASSERT_RTNL();
+	tcx_entry(entry)->miniq_active++;
+}
+
+static inline void tcx_miniq_dec(struct bpf_mprog_entry *entry)
+{
+	ASSERT_RTNL();
+	tcx_entry(entry)->miniq_active--;
+}
+
+static inline bool tcx_entry_is_active(struct bpf_mprog_entry *entry)
+{
+	ASSERT_RTNL();
+	return bpf_mprog_total(entry) || tcx_entry(entry)->miniq_active;
+}
+
+static inline enum tcx_action_base tcx_action_code(struct sk_buff *skb,
+						   int code)
+{
+	switch (code) {
+	case TCX_PASS:
+		skb->tc_index = qdisc_skb_cb(skb)->tc_classid;
+		fallthrough;
+	case TCX_DROP:
+	case TCX_REDIRECT:
+		return code;
+	case TCX_NEXT:
+	default:
+		return TCX_NEXT;
+	}
+}
+#endif /* CONFIG_NET_XGRESS */
+
+#if defined(CONFIG_NET_XGRESS) && defined(CONFIG_BPF_SYSCALL)
+int tcx_prog_attach(const union bpf_attr *attr, struct bpf_prog *prog);
+int tcx_link_attach(const union bpf_attr *attr, struct bpf_prog *prog);
+int tcx_prog_detach(const union bpf_attr *attr, struct bpf_prog *prog);
+void tcx_uninstall(struct net_device *dev, bool ingress);
+
+int tcx_prog_query(const union bpf_attr *attr,
+		   union bpf_attr __user *uattr);
+
+static inline void dev_tcx_uninstall(struct net_device *dev)
+{
+	ASSERT_RTNL();
+	tcx_uninstall(dev, true);
+	tcx_uninstall(dev, false);
+}
+#else
+static inline int tcx_prog_attach(const union bpf_attr *attr,
+				  struct bpf_prog *prog)
+{
+	return -EINVAL;
+}
+
+static inline int tcx_link_attach(const union bpf_attr *attr,
+				  struct bpf_prog *prog)
+{
+	return -EINVAL;
+}
+
+static inline int tcx_prog_detach(const union bpf_attr *attr,
+				  struct bpf_prog *prog)
+{
+	return -EINVAL;
+}
+
+static inline int tcx_prog_query(const union bpf_attr *attr,
+				 union bpf_attr __user *uattr)
+{
+	return -EINVAL;
+}
+
+static inline void dev_tcx_uninstall(struct net_device *dev)
+{
+}
+#endif /* CONFIG_NET_XGRESS && CONFIG_BPF_SYSCALL */
+#endif /* __NET_TCX_H */