From 6668ed271eaefaa63e686bdfbedaeb7b8e492722 Mon Sep 17 00:00:00 2001
From: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Date: Fri, 4 Sep 2026 10:43:19 +0200
Subject: selftests/bpf: Reject graph kptr use after RCU unlock

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>
---
 Documentation/driver-api/basics.rst | 148 ++++++++++++++++++++++++++++++++++++
 1 file changed, 148 insertions(+)
 create mode 100644 Documentation/driver-api/basics.rst

(limited to 'Documentation/driver-api/basics.rst')

diff --git a/Documentation/driver-api/basics.rst b/Documentation/driver-api/basics.rst
new file mode 100644
index 000000000..8b6a5888c
--- /dev/null
+++ b/Documentation/driver-api/basics.rst
@@ -0,0 +1,148 @@
+Driver Basics
+=============
+
+Driver Entry and Exit points
+----------------------------
+
+.. kernel-doc:: include/linux/module.h
+   :internal:
+
+Driver device table
+-------------------
+
+.. kernel-doc:: include/linux/mod_devicetable.h
+   :internal:
+   :no-identifiers: pci_device_id
+
+
+Delaying and scheduling routines
+--------------------------------
+
+.. kernel-doc:: include/linux/sched.h
+   :internal:
+
+.. kernel-doc:: kernel/sched/core.c
+   :export:
+
+.. kernel-doc:: kernel/sched/cpupri.c
+   :internal:
+
+.. kernel-doc:: kernel/sched/fair.c
+   :internal:
+
+.. kernel-doc:: include/linux/completion.h
+   :internal:
+
+Time and timer routines
+-----------------------
+
+.. kernel-doc:: include/linux/jiffies.h
+   :internal:
+
+.. kernel-doc:: kernel/time/time.c
+   :export:
+
+.. kernel-doc:: kernel/time/timer.c
+   :export:
+
+High-resolution timers
+----------------------
+
+.. kernel-doc:: include/linux/ktime.h
+   :internal:
+
+.. kernel-doc:: include/linux/hrtimer.h
+   :internal:
+
+.. kernel-doc:: kernel/time/hrtimer.c
+   :export:
+
+Wait queues and Wake events
+---------------------------
+
+.. kernel-doc:: include/linux/wait.h
+   :internal:
+
+.. kernel-doc:: kernel/sched/wait.c
+   :export:
+
+Internal Functions
+------------------
+
+.. kernel-doc:: kernel/exit.c
+   :internal:
+
+.. kernel-doc:: kernel/signal.c
+   :internal:
+
+.. kernel-doc:: include/linux/kthread.h
+   :internal:
+
+.. kernel-doc:: kernel/kthread.c
+   :export:
+
+Reference counting
+------------------
+
+.. kernel-doc:: include/linux/refcount.h
+   :internal:
+
+.. kernel-doc:: lib/refcount.c
+   :export:
+
+Atomics
+-------
+
+.. kernel-doc:: include/linux/atomic/atomic-instrumented.h
+   :internal:
+
+.. kernel-doc:: include/linux/atomic/atomic-arch-fallback.h
+   :internal:
+
+.. kernel-doc:: include/linux/atomic/atomic-long.h
+   :internal:
+
+Kernel objects manipulation
+---------------------------
+
+.. kernel-doc:: lib/kobject.c
+   :export:
+
+.. kernel-doc:: lib/kobject_uevent.c
+   :export:
+
+Kernel utility functions
+------------------------
+
+.. kernel-doc:: include/linux/array_size.h
+   :internal:
+
+.. kernel-doc:: include/linux/container_of.h
+   :internal:
+
+.. kernel-doc:: include/linux/kstrtox.h
+   :internal:
+   :no-identifiers: kstrtol kstrtoul
+
+.. kernel-doc:: include/linux/stddef.h
+   :internal:
+
+.. kernel-doc:: include/linux/util_macros.h
+   :internal:
+
+.. kernel-doc:: include/linux/wordpart.h
+   :internal:
+
+.. kernel-doc:: kernel/printk/printk.c
+   :export:
+   :no-identifiers: printk
+
+.. kernel-doc:: kernel/panic.c
+   :export:
+
+Device Resource Management
+--------------------------
+
+.. kernel-doc:: drivers/base/devres.c
+   :export:
+
-- 
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