Merge https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

Daniel Borkmann says:

====================
bpf-next 2022-07-22

We've added 73 non-merge commits during the last 12 day(s) which contain
a total of 88 files changed, 3458 insertions(+), 860 deletions(-).

The main changes are:

1) Implement BPF trampoline for arm64 JIT, from Xu Kuohai.

2) Add ksyscall/kretsyscall section support to libbpf to simplify tracing kernel
   syscalls through kprobe mechanism, from Andrii Nakryiko.

3) Allow for livepatch (KLP) and BPF trampolines to attach to the same kernel
   function, from Song Liu & Jiri Olsa.

4) Add new kfunc infrastructure for netfilter's CT e.g. to insert and change
   entries, from Kumar Kartikeya Dwivedi & Lorenzo Bianconi.

5) Add a ksym BPF iterator to allow for more flexible and efficient interactions
   with kernel symbols, from Alan Maguire.

6) Bug fixes in libbpf e.g. for uprobe binary path resolution, from Dan Carpenter.

7) Fix BPF subprog function names in stack traces, from Alexei Starovoitov.

8) libbpf support for writing custom perf event readers, from Jon Doron.

9) Switch to use SPDX tag for BPF helper man page, from Alejandro Colomar.

10) Fix xsk send-only sockets when in busy poll mode, from Maciej Fijalkowski.

11) Reparent BPF maps and their charging on memcg offlining, from Roman Gushchin.

12) Multiple follow-up fixes around BPF lsm cgroup infra, from Stanislav Fomichev.

13) Use bootstrap version of bpftool where possible to speed up builds, from Pu Lehui.

14) Cleanup BPF verifier's check_func_arg() handling, from Joanne Koong.

15) Make non-prealloced BPF map allocations low priority to play better with
    memcg limits, from Yafang Shao.

16) Fix BPF test runner to reject zero-length data for skbs, from Zhengchao Shao.

17) Various smaller cleanups and improvements all over the place.

* https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (73 commits)
  bpf: Simplify bpf_prog_pack_[size|mask]
  bpf: Support bpf_trampoline on functions with IPMODIFY (e.g. livepatch)
  bpf, x64: Allow to use caller address from stack
  ftrace: Allow IPMODIFY and DIRECT ops on the same function
  ftrace: Add modify_ftrace_direct_multi_nolock
  bpf/selftests: Fix couldn't retrieve pinned program in xdp veth test
  bpf: Fix build error in case of !CONFIG_DEBUG_INFO_BTF
  selftests/bpf: Fix test_verifier failed test in unprivileged mode
  selftests/bpf: Add negative tests for new nf_conntrack kfuncs
  selftests/bpf: Add tests for new nf_conntrack kfuncs
  selftests/bpf: Add verifier tests for trusted kfunc args
  net: netfilter: Add kfuncs to set and change CT status
  net: netfilter: Add kfuncs to set and change CT timeout
  net: netfilter: Add kfuncs to allocate and insert CT
  net: netfilter: Deduplicate code in bpf_{xdp,skb}_ct_lookup
  bpf: Add documentation for kfuncs
  bpf: Add support for forcing kfunc args to be trusted
  bpf: Switch to new kfunc flags infrastructure
  tools/resolve_btfids: Add support for 8-byte BTF sets
  bpf: Introduce 8-byte BTF set
  ...
====================

Link: https://lore.kernel.org/r/20220722221218.29943-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 278 insertions, 50 deletions

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 601ccf1b2f09..bc921a3f7ea8 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -1861,6 +1861,8 @@ static void ftrace_hash_rec_enable_modify(struct ftrace_ops *ops,
 	ftrace_hash_rec_update_modify(ops, filter_hash, 1);
 }
 
+static bool ops_references_ip(struct ftrace_ops *ops, unsigned long ip);
+
 /*
  * Try to update IPMODIFY flag on each ftrace_rec. Return 0 if it is OK
  * or no-needed to update, -EBUSY if it detects a conflict of the flag
@@ -1869,6 +1871,13 @@ static void ftrace_hash_rec_enable_modify(struct ftrace_ops *ops,
  *  - If the hash is NULL, it hits all recs (if IPMODIFY is set, this is rejected)
  *  - If the hash is EMPTY_HASH, it hits nothing
  *  - Anything else hits the recs which match the hash entries.
+ *
+ * DIRECT ops does not have IPMODIFY flag, but we still need to check it
+ * against functions with FTRACE_FL_IPMODIFY. If there is any overlap, call
+ * ops_func(SHARE_IPMODIFY_SELF) to make sure current ops can share with
+ * IPMODIFY. If ops_func(SHARE_IPMODIFY_SELF) returns non-zero, propagate
+ * the return value to the caller and eventually to the owner of the DIRECT
+ * ops.
  */
 static int __ftrace_hash_update_ipmodify(struct ftrace_ops *ops,
 					 struct ftrace_hash *old_hash,
@@ -1877,17 +1886,26 @@ static int __ftrace_hash_update_ipmodify(struct ftrace_ops *ops,
 	struct ftrace_page *pg;
 	struct dyn_ftrace *rec, *end = NULL;
 	int in_old, in_new;
+	bool is_ipmodify, is_direct;
 
 	/* Only update if the ops has been registered */
 	if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
 		return 0;
 
-	if (!(ops->flags & FTRACE_OPS_FL_IPMODIFY))
+	is_ipmodify = ops->flags & FTRACE_OPS_FL_IPMODIFY;
+	is_direct = ops->flags & FTRACE_OPS_FL_DIRECT;
+
+	/* neither IPMODIFY nor DIRECT, skip */
+	if (!is_ipmodify && !is_direct)
+		return 0;
+
+	if (WARN_ON_ONCE(is_ipmodify && is_direct))
 		return 0;
 
 	/*
-	 * Since the IPMODIFY is a very address sensitive action, we do not
-	 * allow ftrace_ops to set all functions to new hash.
+	 * Since the IPMODIFY and DIRECT are very address sensitive
+	 * actions, we do not allow ftrace_ops to set all functions to new
+	 * hash.
 	 */
 	if (!new_hash || !old_hash)
 		return -EINVAL;
@@ -1905,12 +1923,32 @@ static int __ftrace_hash_update_ipmodify(struct ftrace_ops *ops,
 			continue;
 
 		if (in_new) {
-			/* New entries must ensure no others are using it */
-			if (rec->flags & FTRACE_FL_IPMODIFY)
-				goto rollback;
-			rec->flags |= FTRACE_FL_IPMODIFY;
-		} else /* Removed entry */
+			if (rec->flags & FTRACE_FL_IPMODIFY) {
+				int ret;
+
+				/* Cannot have two ipmodify on same rec */
+				if (is_ipmodify)
+					goto rollback;
+
+				FTRACE_WARN_ON(rec->flags & FTRACE_FL_DIRECT);
+
+				/*
+				 * Another ops with IPMODIFY is already
+				 * attached. We are now attaching a direct
+				 * ops. Run SHARE_IPMODIFY_SELF, to check
+				 * whether sharing is supported.
+				 */
+				if (!ops->ops_func)
+					return -EBUSY;
+				ret = ops->ops_func(ops, FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_SELF);
+				if (ret)
+					return ret;
+			} else if (is_ipmodify) {
+				rec->flags |= FTRACE_FL_IPMODIFY;
+			}
+		} else if (is_ipmodify) {
 			rec->flags &= ~FTRACE_FL_IPMODIFY;
+		}
 	} while_for_each_ftrace_rec();
 
 	return 0;
@@ -2454,8 +2492,7 @@ static void call_direct_funcs(unsigned long ip, unsigned long pip,
 
 struct ftrace_ops direct_ops = {
 	.func		= call_direct_funcs,
-	.flags		= FTRACE_OPS_FL_IPMODIFY
-			  | FTRACE_OPS_FL_DIRECT | FTRACE_OPS_FL_SAVE_REGS
+	.flags		= FTRACE_OPS_FL_DIRECT | FTRACE_OPS_FL_SAVE_REGS
 			  | FTRACE_OPS_FL_PERMANENT,
 	/*
 	 * By declaring the main trampoline as this trampoline
@@ -3072,14 +3109,14 @@ static inline int ops_traces_mod(struct ftrace_ops *ops)
 }
 
 /*
- * Check if the current ops references the record.
+ * Check if the current ops references the given ip.
  *
  * If the ops traces all functions, then it was already accounted for.
  * If the ops does not trace the current record function, skip it.
  * If the ops ignores the function via notrace filter, skip it.
  */
-static inline bool
-ops_references_rec(struct ftrace_ops *ops, struct dyn_ftrace *rec)
+static bool
+ops_references_ip(struct ftrace_ops *ops, unsigned long ip)
 {
 	/* If ops isn't enabled, ignore it */
 	if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
@@ -3091,16 +3128,29 @@ ops_references_rec(struct ftrace_ops *ops, struct dyn_ftrace *rec)
 
 	/* The function must be in the filter */
 	if (!ftrace_hash_empty(ops->func_hash->filter_hash) &&
-	    !__ftrace_lookup_ip(ops->func_hash->filter_hash, rec->ip))
+	    !__ftrace_lookup_ip(ops->func_hash->filter_hash, ip))
 		return false;
 
 	/* If in notrace hash, we ignore it too */
-	if (ftrace_lookup_ip(ops->func_hash->notrace_hash, rec->ip))
+	if (ftrace_lookup_ip(ops->func_hash->notrace_hash, ip))
 		return false;
 
 	return true;
 }
 
+/*
+ * Check if the current ops references the record.
+ *
+ * If the ops traces all functions, then it was already accounted for.
+ * If the ops does not trace the current record function, skip it.
+ * If the ops ignores the function via notrace filter, skip it.
+ */
+static bool
+ops_references_rec(struct ftrace_ops *ops, struct dyn_ftrace *rec)
+{
+	return ops_references_ip(ops, rec->ip);
+}
+
 static int ftrace_update_code(struct module *mod, struct ftrace_page *new_pgs)
 {
 	bool init_nop = ftrace_need_init_nop();
@@ -5215,6 +5265,8 @@ static struct ftrace_direct_func *ftrace_alloc_direct_func(unsigned long addr)
 	return direct;
 }
 
+static int register_ftrace_function_nolock(struct ftrace_ops *ops);
+
 /**
  * register_ftrace_direct - Call a custom trampoline directly
  * @ip: The address of the nop at the beginning of a function
@@ -5286,7 +5338,7 @@ int register_ftrace_direct(unsigned long ip, unsigned long addr)
 	ret = ftrace_set_filter_ip(&direct_ops, ip, 0, 0);
 
 	if (!ret && !(direct_ops.flags & FTRACE_OPS_FL_ENABLED)) {
-		ret = register_ftrace_function(&direct_ops);
+		ret = register_ftrace_function_nolock(&direct_ops);
 		if (ret)
 			ftrace_set_filter_ip(&direct_ops, ip, 1, 0);
 	}
@@ -5545,8 +5597,7 @@ int modify_ftrace_direct(unsigned long ip,
 }
 EXPORT_SYMBOL_GPL(modify_ftrace_direct);
 
-#define MULTI_FLAGS (FTRACE_OPS_FL_IPMODIFY | FTRACE_OPS_FL_DIRECT | \
-		     FTRACE_OPS_FL_SAVE_REGS)
+#define MULTI_FLAGS (FTRACE_OPS_FL_DIRECT | FTRACE_OPS_FL_SAVE_REGS)
 
 static int check_direct_multi(struct ftrace_ops *ops)
 {
@@ -5639,7 +5690,7 @@ int register_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr)
 	ops->flags = MULTI_FLAGS;
 	ops->trampoline = FTRACE_REGS_ADDR;
 
-	err = register_ftrace_function(ops);
+	err = register_ftrace_function_nolock(ops);
 
  out_remove:
 	if (err)
@@ -5691,22 +5742,8 @@ int unregister_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr)
 }
 EXPORT_SYMBOL_GPL(unregister_ftrace_direct_multi);
 
-/**
- * modify_ftrace_direct_multi - Modify an existing direct 'multi' call
- * to call something else
- * @ops: The address of the struct ftrace_ops object
- * @addr: The address of the new trampoline to call at @ops functions
- *
- * This is used to unregister currently registered direct caller and
- * register new one @addr on functions registered in @ops object.
- *
- * Note there's window between ftrace_shutdown and ftrace_startup calls
- * where there will be no callbacks called.
- *
- * Returns: zero on success. Non zero on error, which includes:
- *  -EINVAL - The @ops object was not properly registered.
- */
-int modify_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr)
+static int
+__modify_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr)
 {
 	struct ftrace_hash *hash;
 	struct ftrace_func_entry *entry, *iter;
@@ -5717,20 +5754,15 @@ int modify_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr)
 	int i, size;
 	int err;
 
-	if (check_direct_multi(ops))
-		return -EINVAL;
-	if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
-		return -EINVAL;
-
-	mutex_lock(&direct_mutex);
+	lockdep_assert_held_once(&direct_mutex);
 
 	/* Enable the tmp_ops to have the same functions as the direct ops */
 	ftrace_ops_init(&tmp_ops);
 	tmp_ops.func_hash = ops->func_hash;
 
-	err = register_ftrace_function(&tmp_ops);
+	err = register_ftrace_function_nolock(&tmp_ops);
 	if (err)
-		goto out_direct;
+		return err;
 
 	/*
 	 * Now the ftrace_ops_list_func() is called to do the direct callers.
@@ -5754,7 +5786,64 @@ int modify_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr)
 	/* Removing the tmp_ops will add the updated direct callers to the functions */
 	unregister_ftrace_function(&tmp_ops);
 
- out_direct:
+	return err;
+}
+
+/**
+ * modify_ftrace_direct_multi_nolock - Modify an existing direct 'multi' call
+ * to call something else
+ * @ops: The address of the struct ftrace_ops object
+ * @addr: The address of the new trampoline to call at @ops functions
+ *
+ * This is used to unregister currently registered direct caller and
+ * register new one @addr on functions registered in @ops object.
+ *
+ * Note there's window between ftrace_shutdown and ftrace_startup calls
+ * where there will be no callbacks called.
+ *
+ * Caller should already have direct_mutex locked, so we don't lock
+ * direct_mutex here.
+ *
+ * Returns: zero on success. Non zero on error, which includes:
+ *  -EINVAL - The @ops object was not properly registered.
+ */
+int modify_ftrace_direct_multi_nolock(struct ftrace_ops *ops, unsigned long addr)
+{
+	if (check_direct_multi(ops))
+		return -EINVAL;
+	if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
+		return -EINVAL;
+
+	return __modify_ftrace_direct_multi(ops, addr);
+}
+EXPORT_SYMBOL_GPL(modify_ftrace_direct_multi_nolock);
+
+/**
+ * modify_ftrace_direct_multi - Modify an existing direct 'multi' call
+ * to call something else
+ * @ops: The address of the struct ftrace_ops object
+ * @addr: The address of the new trampoline to call at @ops functions
+ *
+ * This is used to unregister currently registered direct caller and
+ * register new one @addr on functions registered in @ops object.
+ *
+ * Note there's window between ftrace_shutdown and ftrace_startup calls
+ * where there will be no callbacks called.
+ *
+ * Returns: zero on success. Non zero on error, which includes:
+ *  -EINVAL - The @ops object was not properly registered.
+ */
+int modify_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr)
+{
+	int err;
+
+	if (check_direct_multi(ops))
+		return -EINVAL;
+	if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
+		return -EINVAL;
+
+	mutex_lock(&direct_mutex);
+	err = __modify_ftrace_direct_multi(ops, addr);
 	mutex_unlock(&direct_mutex);
 	return err;
 }
@@ -7965,6 +8054,143 @@ int ftrace_is_dead(void)
 	return ftrace_disabled;
 }
 
+#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
+/*
+ * When registering ftrace_ops with IPMODIFY, it is necessary to make sure
+ * it doesn't conflict with any direct ftrace_ops. If there is existing
+ * direct ftrace_ops on a kernel function being patched, call
+ * FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_PEER on it to enable sharing.
+ *
+ * @ops:     ftrace_ops being registered.
+ *
+ * Returns:
+ *         0 on success;
+ *         Negative on failure.
+ */
+static int prepare_direct_functions_for_ipmodify(struct ftrace_ops *ops)
+{
+	struct ftrace_func_entry *entry;
+	struct ftrace_hash *hash;
+	struct ftrace_ops *op;
+	int size, i, ret;
+
+	lockdep_assert_held_once(&direct_mutex);
+
+	if (!(ops->flags & FTRACE_OPS_FL_IPMODIFY))
+		return 0;
+
+	hash = ops->func_hash->filter_hash;
+	size = 1 << hash->size_bits;
+	for (i = 0; i < size; i++) {
+		hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
+			unsigned long ip = entry->ip;
+			bool found_op = false;
+
+			mutex_lock(&ftrace_lock);
+			do_for_each_ftrace_op(op, ftrace_ops_list) {
+				if (!(op->flags & FTRACE_OPS_FL_DIRECT))
+					continue;
+				if (ops_references_ip(op, ip)) {
+					found_op = true;
+					break;
+				}
+			} while_for_each_ftrace_op(op);
+			mutex_unlock(&ftrace_lock);
+
+			if (found_op) {
+				if (!op->ops_func)
+					return -EBUSY;
+
+				ret = op->ops_func(op, FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_PEER);
+				if (ret)
+					return ret;
+			}
+		}
+	}
+
+	return 0;
+}
+
+/*
+ * Similar to prepare_direct_functions_for_ipmodify, clean up after ops
+ * with IPMODIFY is unregistered. The cleanup is optional for most DIRECT
+ * ops.
+ */
+static void cleanup_direct_functions_after_ipmodify(struct ftrace_ops *ops)
+{
+	struct ftrace_func_entry *entry;
+	struct ftrace_hash *hash;
+	struct ftrace_ops *op;
+	int size, i;
+
+	if (!(ops->flags & FTRACE_OPS_FL_IPMODIFY))
+		return;
+
+	mutex_lock(&direct_mutex);
+
+	hash = ops->func_hash->filter_hash;
+	size = 1 << hash->size_bits;
+	for (i = 0; i < size; i++) {
+		hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
+			unsigned long ip = entry->ip;
+			bool found_op = false;
+
+			mutex_lock(&ftrace_lock);
+			do_for_each_ftrace_op(op, ftrace_ops_list) {
+				if (!(op->flags & FTRACE_OPS_FL_DIRECT))
+					continue;
+				if (ops_references_ip(op, ip)) {
+					found_op = true;
+					break;
+				}
+			} while_for_each_ftrace_op(op);
+			mutex_unlock(&ftrace_lock);
+
+			/* The cleanup is optional, ignore any errors */
+			if (found_op && op->ops_func)
+				op->ops_func(op, FTRACE_OPS_CMD_DISABLE_SHARE_IPMODIFY_PEER);
+		}
+	}
+	mutex_unlock(&direct_mutex);
+}
+
+#define lock_direct_mutex()	mutex_lock(&direct_mutex)
+#define unlock_direct_mutex()	mutex_unlock(&direct_mutex)
+
+#else  /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
+
+static int prepare_direct_functions_for_ipmodify(struct ftrace_ops *ops)
+{
+	return 0;
+}
+
+static void cleanup_direct_functions_after_ipmodify(struct ftrace_ops *ops)
+{
+}
+
+#define lock_direct_mutex()	do { } while (0)
+#define unlock_direct_mutex()	do { } while (0)
+
+#endif  /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
+
+/*
+ * Similar to register_ftrace_function, except we don't lock direct_mutex.
+ */
+static int register_ftrace_function_nolock(struct ftrace_ops *ops)
+{
+	int ret;
+
+	ftrace_ops_init(ops);
+
+	mutex_lock(&ftrace_lock);
+
+	ret = ftrace_startup(ops, 0);
+
+	mutex_unlock(&ftrace_lock);
+
+	return ret;
+}
+
 /**
  * register_ftrace_function - register a function for profiling
  * @ops:	ops structure that holds the function for profiling.
@@ -7980,14 +8206,15 @@ int register_ftrace_function(struct ftrace_ops *ops)
 {
 	int ret;
 
-	ftrace_ops_init(ops);
-
-	mutex_lock(&ftrace_lock);
-
-	ret = ftrace_startup(ops, 0);
+	lock_direct_mutex();
+	ret = prepare_direct_functions_for_ipmodify(ops);
+	if (ret < 0)
+		goto out_unlock;
 
-	mutex_unlock(&ftrace_lock);
+	ret = register_ftrace_function_nolock(ops);
 
+out_unlock:
+	unlock_direct_mutex();
 	return ret;
 }
 EXPORT_SYMBOL_GPL(register_ftrace_function);
@@ -8006,6 +8233,7 @@ int unregister_ftrace_function(struct ftrace_ops *ops)
 	ret = ftrace_shutdown(ops, 0);
 	mutex_unlock(&ftrace_lock);
 
+	cleanup_direct_functions_after_ipmodify(ops);
 	return ret;
 }
 EXPORT_SYMBOL_GPL(unregister_ftrace_function);