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

Daniel Borkmann says:

====================
pull-request: bpf-next 2022-10-03

We've added 143 non-merge commits during the last 27 day(s) which contain
a total of 151 files changed, 8321 insertions(+), 1402 deletions(-).

The main changes are:

1) Add kfuncs for PKCS#7 signature verification from BPF programs, from Roberto Sassu.

2) Add support for struct-based arguments for trampoline based BPF programs,
   from Yonghong Song.

3) Fix entry IP for kprobe-multi and trampoline probes under IBT enabled, from Jiri Olsa.

4) Batch of improvements to veristat selftest tool in particular to add CSV output,
   a comparison mode for CSV outputs and filtering, from Andrii Nakryiko.

5) Add preparatory changes needed for the BPF core for upcoming BPF HID support,
   from Benjamin Tissoires.

6) Support for direct writes to nf_conn's mark field from tc and XDP BPF program
   types, from Daniel Xu.

7) Initial batch of documentation improvements for BPF insn set spec, from Dave Thaler.

8) Add a new BPF_MAP_TYPE_USER_RINGBUF map which provides single-user-space-producer /
   single-kernel-consumer semantics for BPF ring buffer, from David Vernet.

9) Follow-up fixes to BPF allocator under RT to always use raw spinlock for the BPF
   hashtab's bucket lock, from Hou Tao.

10) Allow creating an iterator that loops through only the resources of one
    task/thread instead of all, from Kui-Feng Lee.

11) Add support for kptrs in the per-CPU arraymap, from Kumar Kartikeya Dwivedi.

12) Add a new kfunc helper for nf to set src/dst NAT IP/port in a newly allocated CT
    entry which is not yet inserted, from Lorenzo Bianconi.

13) Remove invalid recursion check for struct_ops for TCP congestion control BPF
    programs, from Martin KaFai Lau.

14) Fix W^X issue with BPF trampoline and BPF dispatcher, from Song Liu.

15) Fix percpu_counter leakage in BPF hashtab allocation error path, from Tetsuo Handa.

16) Various cleanups in BPF selftests to use preferred ASSERT_* macros, from Wang Yufen.

17) Add invocation for cgroup/connect{4,6} BPF programs for ICMP pings, from YiFei Zhu.

18) Lift blinding decision under bpf_jit_harden = 1 to bpf_capable(), from Yauheni Kaliuta.

19) Various libbpf fixes and cleanups including a libbpf NULL pointer deref, from Xin Liu.

* https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (143 commits)
  net: netfilter: move bpf_ct_set_nat_info kfunc in nf_nat_bpf.c
  Documentation: bpf: Add implementation notes documentations to table of contents
  bpf, docs: Delete misformatted table.
  selftests/xsk: Fix double free
  bpftool: Fix error message of strerror
  libbpf: Fix overrun in netlink attribute iteration
  selftests/bpf: Fix spelling mistake "unpriviledged" -> "unprivileged"
  samples/bpf: Fix typo in xdp_router_ipv4 sample
  bpftool: Remove unused struct event_ring_info
  bpftool: Remove unused struct btf_attach_point
  bpf, docs: Add TOC and fix formatting.
  bpf, docs: Add Clang note about BPF_ALU
  bpf, docs: Move Clang notes to a separate file
  bpf, docs: Linux byteswap note
  bpf, docs: Move legacy packet instructions to a separate file
  selftests/bpf: Check -EBUSY for the recurred bpf_setsockopt(TCP_CONGESTION)
  bpf: tcp: Stop bpf_setsockopt(TCP_CONGESTION) in init ops to recur itself
  bpf: Refactor bpf_setsockopt(TCP_CONGESTION) handling into another function
  bpf: Move the "cdg" tcp-cc check to the common sol_tcp_sockopt()
  bpf: Add __bpf_prog_{enter,exit}_struct_ops for struct_ops trampoline
  ...
====================

Link: https://lore.kernel.org/r/20221003194915.11847-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 16 insertions, 52 deletions

diff --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c
index 0fe3f136cbbe..ed3f8a53603b 100644
--- a/kernel/bpf/hashtab.c
+++ b/kernel/bpf/hashtab.c
@@ -68,24 +68,16 @@
  * In theory the BPF locks could be converted to regular spinlocks as well,
  * but the bucket locks and percpu_freelist locks can be taken from
  * arbitrary contexts (perf, kprobes, tracepoints) which are required to be
- * atomic contexts even on RT. These mechanisms require preallocated maps,
- * so there is no need to invoke memory allocations within the lock held
- * sections.
- *
- * BPF maps which need dynamic allocation are only used from (forced)
- * thread context on RT and can therefore use regular spinlocks which in
- * turn allows to invoke memory allocations from the lock held section.
- *
- * On a non RT kernel this distinction is neither possible nor required.
- * spinlock maps to raw_spinlock and the extra code is optimized out by the
- * compiler.
+ * atomic contexts even on RT. Before the introduction of bpf_mem_alloc,
+ * it is only safe to use raw spinlock for preallocated hash map on a RT kernel,
+ * because there is no memory allocation within the lock held sections. However
+ * after hash map was fully converted to use bpf_mem_alloc, there will be
+ * non-synchronous memory allocation for non-preallocated hash map, so it is
+ * safe to always use raw spinlock for bucket lock.
  */
 struct bucket {
 	struct hlist_nulls_head head;
-	union {
-		raw_spinlock_t raw_lock;
-		spinlock_t     lock;
-	};
+	raw_spinlock_t raw_lock;
 };
 
 #define HASHTAB_MAP_LOCK_COUNT 8
@@ -141,26 +133,15 @@ static inline bool htab_is_prealloc(const struct bpf_htab *htab)
 	return !(htab->map.map_flags & BPF_F_NO_PREALLOC);
 }
 
-static inline bool htab_use_raw_lock(const struct bpf_htab *htab)
-{
-	return (!IS_ENABLED(CONFIG_PREEMPT_RT) || htab_is_prealloc(htab));
-}
-
 static void htab_init_buckets(struct bpf_htab *htab)
 {
 	unsigned int i;
 
 	for (i = 0; i < htab->n_buckets; i++) {
 		INIT_HLIST_NULLS_HEAD(&htab->buckets[i].head, i);
-		if (htab_use_raw_lock(htab)) {
-			raw_spin_lock_init(&htab->buckets[i].raw_lock);
-			lockdep_set_class(&htab->buckets[i].raw_lock,
-					  &htab->lockdep_key);
-		} else {
-			spin_lock_init(&htab->buckets[i].lock);
-			lockdep_set_class(&htab->buckets[i].lock,
+		raw_spin_lock_init(&htab->buckets[i].raw_lock);
+		lockdep_set_class(&htab->buckets[i].raw_lock,
 					  &htab->lockdep_key);
-		}
 		cond_resched();
 	}
 }
@@ -170,28 +151,17 @@ static inline int htab_lock_bucket(const struct bpf_htab *htab,
 				   unsigned long *pflags)
 {
 	unsigned long flags;
-	bool use_raw_lock;
 
 	hash = hash & HASHTAB_MAP_LOCK_MASK;
 
-	use_raw_lock = htab_use_raw_lock(htab);
-	if (use_raw_lock)
-		preempt_disable();
-	else
-		migrate_disable();
+	preempt_disable();
 	if (unlikely(__this_cpu_inc_return(*(htab->map_locked[hash])) != 1)) {
 		__this_cpu_dec(*(htab->map_locked[hash]));
-		if (use_raw_lock)
-			preempt_enable();
-		else
-			migrate_enable();
+		preempt_enable();
 		return -EBUSY;
 	}
 
-	if (use_raw_lock)
-		raw_spin_lock_irqsave(&b->raw_lock, flags);
-	else
-		spin_lock_irqsave(&b->lock, flags);
+	raw_spin_lock_irqsave(&b->raw_lock, flags);
 	*pflags = flags;
 
 	return 0;
@@ -201,18 +171,10 @@ static inline void htab_unlock_bucket(const struct bpf_htab *htab,
 				      struct bucket *b, u32 hash,
 				      unsigned long flags)
 {
-	bool use_raw_lock = htab_use_raw_lock(htab);
-
 	hash = hash & HASHTAB_MAP_LOCK_MASK;
-	if (use_raw_lock)
-		raw_spin_unlock_irqrestore(&b->raw_lock, flags);
-	else
-		spin_unlock_irqrestore(&b->lock, flags);
+	raw_spin_unlock_irqrestore(&b->raw_lock, flags);
 	__this_cpu_dec(*(htab->map_locked[hash]));
-	if (use_raw_lock)
-		preempt_enable();
-	else
-		migrate_enable();
+	preempt_enable();
 }
 
 static bool htab_lru_map_delete_node(void *arg, struct bpf_lru_node *node);
@@ -622,6 +584,8 @@ static struct bpf_map *htab_map_alloc(union bpf_attr *attr)
 free_prealloc:
 	prealloc_destroy(htab);
 free_map_locked:
+	if (htab->use_percpu_counter)
+		percpu_counter_destroy(&htab->pcount);
 	for (i = 0; i < HASHTAB_MAP_LOCK_COUNT; i++)
 		free_percpu(htab->map_locked[i]);
 	bpf_map_area_free(htab->buckets);