bpf: mark a NULL kfunc argument precisegrafted

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>

1 files changed, 58 insertions, 0 deletions

diff --git a/net/hsr/Kconfig b/net/hsr/Kconfig
new file mode 100644
index 000000000..fcacdf4f0
--- /dev/null
+++ b/net/hsr/Kconfig
@@ -0,0 +1,58 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# IEC 62439-3 High-availability Seamless Redundancy
+#
+
+config HSR
+	tristate "High-availability Seamless Redundancy (HSR & PRP)"
+	help
+	  This enables IEC 62439 defined High-availability Seamless
+	  Redundancy (HSR) and Parallel Redundancy Protocol (PRP).
+
+	  If you say Y here, then your Linux box will be able to act as a
+	  DANH ("Doubly attached node implementing HSR") or DANP ("Doubly
+	  attached node implementing PRP"). For this to work, your Linux box
+	  needs (at least) two physical Ethernet interfaces.
+
+	  For DANH, it must be connected as a node in a ring network together
+	  with other HSR capable nodes. All Ethernet frames sent over the HSR
+	  device will be sent in both directions on the ring (over both slave
+	  ports), giving a redundant, instant fail-over network. Each HSR node
+	  in the ring acts like a bridge for HSR frames, but filters frames
+	  that have been forwarded earlier.
+
+	  For DANP, it must be connected as a node connecting to two
+	  separate networks over the two slave interfaces. Like HSR, Ethernet
+	  frames sent over the PRP device will be sent to both networks giving
+	  a redundant, instant fail-over network. Unlike HSR, PRP networks
+	  can have Singly Attached Nodes (SAN) such as PC, printer, bridges
+	  etc and will be able to communicate with DANP nodes.
+
+	  This code is a "best effort" to comply with the HSR standard as
+	  described in IEC 62439-3:2010 (HSRv0) and IEC 62439-3:2012 (HSRv1),
+	  and PRP standard described in IEC 62439-4:2012 (PRP), but no
+	  compliancy tests have been made. Use iproute2 to select the protocol
+	  you would like to use.
+
+	  You need to perform any and all necessary tests yourself before
+	  relying on this code in a safety critical system!
+
+	  If unsure, say N.
+
+if HSR
+
+config PRP_DUP_DISCARD_KUNIT_TEST
+	tristate "PRP duplicate discard KUnit tests" if !KUNIT_ALL_TESTS
+	depends on KUNIT
+	default KUNIT_ALL_TESTS
+	help
+	  Covers the PRP duplicate discard algorithm.
+	  Only useful for kernel devs running KUnit test harness and are not
+	  for inclusion into a production build.
+
+	  For more information on KUnit and unit tests in general please refer
+	  to the KUnit documentation in Documentation/dev-tools/kunit/.
+
+	  If unsure, say N.
+
+endif