selftests/bpf: Reject graph kptr use after RCU unlockgrafted

Add a sleepable verifier test that loads a graph-node local kptr in an
explicit RCU read-side critical section, then passes its node to
bpf_rbtree_remove() after the section ends.

Before the verifier fix, the stale NON_OWN_REF flag makes the node look like
a live borrowed reference and the program is accepted. After the fix, the
pointer is demoted without NON_OWN_REF and the graph kfunc argument is
rejected.

Also exercise a graph kptr loaded while a spin lock provides implicit RCU
protection. The pointer must be invalidated when the lock is released, which
guards the required ordering between non-owning-reference invalidation and
RCU demotion.

Update the existing fault-protected load test state description. The
post-unlock pointer no longer carries NON_OWN_REF, but remains readable
because the load is rewritten to use BPF_PROBE_MEM.

Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20260904084325.52250-7-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

4 files changed, 120 insertions, 0 deletions

diff --git a/Documentation/features/locking/cmpxchg-local/arch-support.txt b/Documentation/features/locking/cmpxchg-local/arch-support.txt
new file mode 100644
index 000000000..2c3a4b91f
--- /dev/null
+++ b/Documentation/features/locking/cmpxchg-local/arch-support.txt
@@ -0,0 +1,30 @@
+#
+# Feature name:          cmpxchg-local
+#         Kconfig:       HAVE_CMPXCHG_LOCAL
+#         description:   arch supports the this_cpu_cmpxchg() API
+#
+    -----------------------
+    |         arch |status|
+    -----------------------
+    |       alpha: | TODO |
+    |         arc: | TODO |
+    |         arm: | TODO |
+    |       arm64: |  ok  |
+    |        csky: | TODO |
+    |     hexagon: | TODO |
+    |   loongarch: | TODO |
+    |        m68k: | TODO |
+    |  microblaze: | TODO |
+    |        mips: | TODO |
+    |       nios2: | TODO |
+    |    openrisc: | TODO |
+    |      parisc: | TODO |
+    |     powerpc: | TODO |
+    |       riscv: | TODO |
+    |        s390: |  ok  |
+    |          sh: | TODO |
+    |       sparc: | TODO |
+    |          um: | TODO |
+    |         x86: |  ok  |
+    |      xtensa: | TODO |
+    -----------------------
diff --git a/Documentation/features/locking/lockdep/arch-support.txt b/Documentation/features/locking/lockdep/arch-support.txt
new file mode 100644
index 000000000..87a534c89
--- /dev/null
+++ b/Documentation/features/locking/lockdep/arch-support.txt
@@ -0,0 +1,30 @@
+#
+# Feature name:          lockdep
+#         Kconfig:       LOCKDEP_SUPPORT
+#         description:   arch supports the runtime locking correctness debug facility
+#
+    -----------------------
+    |         arch |status|
+    -----------------------
+    |       alpha: |  ok  |
+    |         arc: |  ok  |
+    |         arm: |  ok  |
+    |       arm64: |  ok  |
+    |        csky: |  ok  |
+    |     hexagon: |  ok  |
+    |   loongarch: |  ok  |
+    |        m68k: | TODO |
+    |  microblaze: |  ok  |
+    |        mips: |  ok  |
+    |       nios2: | TODO |
+    |    openrisc: |  ok  |
+    |      parisc: |  ok  |
+    |     powerpc: |  ok  |
+    |       riscv: |  ok  |
+    |        s390: |  ok  |
+    |          sh: |  ok  |
+    |       sparc: |  ok  |
+    |          um: |  ok  |
+    |         x86: |  ok  |
+    |      xtensa: |  ok  |
+    -----------------------
diff --git a/Documentation/features/locking/queued-rwlocks/arch-support.txt b/Documentation/features/locking/queued-rwlocks/arch-support.txt
new file mode 100644
index 000000000..b286a5fff
--- /dev/null
+++ b/Documentation/features/locking/queued-rwlocks/arch-support.txt
@@ -0,0 +1,30 @@
+#
+# Feature name:          queued-rwlocks
+#         Kconfig:       ARCH_USE_QUEUED_RWLOCKS
+#         description:   arch supports queued rwlocks
+#
+    -----------------------
+    |         arch |status|
+    -----------------------
+    |       alpha: | TODO |
+    |         arc: | TODO |
+    |         arm: | TODO |
+    |       arm64: |  ok  |
+    |        csky: |  ok  |
+    |     hexagon: | TODO |
+    |   loongarch: |  ok  |
+    |        m68k: | TODO |
+    |  microblaze: | TODO |
+    |        mips: |  ok  |
+    |       nios2: | TODO |
+    |    openrisc: |  ok  |
+    |      parisc: | TODO |
+    |     powerpc: |  ok  |
+    |       riscv: |  ok  |
+    |        s390: | TODO |
+    |          sh: | TODO |
+    |       sparc: |  ok  |
+    |          um: | TODO |
+    |         x86: |  ok  |
+    |      xtensa: |  ok  |
+    -----------------------
diff --git a/Documentation/features/locking/queued-spinlocks/arch-support.txt b/Documentation/features/locking/queued-spinlocks/arch-support.txt
new file mode 100644
index 000000000..cf2604248
--- /dev/null
+++ b/Documentation/features/locking/queued-spinlocks/arch-support.txt
@@ -0,0 +1,30 @@
+#
+# Feature name:          queued-spinlocks
+#         Kconfig:       ARCH_USE_QUEUED_SPINLOCKS
+#         description:   arch supports queued spinlocks
+#
+    -----------------------
+    |         arch |status|
+    -----------------------
+    |       alpha: | TODO |
+    |         arc: | TODO |
+    |         arm: | TODO |
+    |       arm64: |  ok  |
+    |        csky: |  ok  |
+    |     hexagon: | TODO |
+    |   loongarch: |  ok  |
+    |        m68k: | TODO |
+    |  microblaze: | TODO |
+    |        mips: |  ok  |
+    |       nios2: | TODO |
+    |    openrisc: |  ok  |
+    |      parisc: | TODO |
+    |     powerpc: |  ok  |
+    |       riscv: |  ok  |
+    |        s390: | TODO |
+    |          sh: | TODO |
+    |       sparc: |  ok  |
+    |          um: | TODO |
+    |         x86: |  ok  |
+    |      xtensa: |  ok  |
+    -----------------------