From 506ada89629ec7059b96ecfb0dc7d33ece0103ca Mon Sep 17 00:00:00 2001
From: Eduard Zingerman <eddyz87@gmail.com>
Date: Fri, 4 Sep 2026 17:05:56 -0700
Subject: bpf: mark a NULL kfunc argument precise

check_kfunc_arg() allows bpf_register_is_null() for nullable arguments
w/o marking the underlying scalar register precise. Hence a checkpoint
created on such a path would prune against arbitrary scalar value.

Fixes: 3bda08b63670 ("bpf: Allow NULL buffers in bpf_dynptr_slice(_rw)")
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20260904-register-is-null-precise-fixes-v1-5-0f5a360ff15d@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
---
 .../locking/cmpxchg-local/arch-support.txt         | 30 ++++++++++++++++++++++
 .../features/locking/lockdep/arch-support.txt      | 30 ++++++++++++++++++++++
 .../locking/queued-rwlocks/arch-support.txt        | 30 ++++++++++++++++++++++
 .../locking/queued-spinlocks/arch-support.txt      | 30 ++++++++++++++++++++++
 4 files changed, 120 insertions(+)
 create mode 100644 Documentation/features/locking/cmpxchg-local/arch-support.txt
 create mode 100644 Documentation/features/locking/lockdep/arch-support.txt
 create mode 100644 Documentation/features/locking/queued-rwlocks/arch-support.txt
 create mode 100644 Documentation/features/locking/queued-spinlocks/arch-support.txt

(limited to 'Documentation/features/locking')

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  |
+    -----------------------
-- 
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