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, 23 insertions, 0 deletions

diff --git a/net/dcb/Kconfig b/net/dcb/Kconfig
new file mode 100644
index 000000000..efee8b9fe
--- /dev/null
+++ b/net/dcb/Kconfig
@@ -0,0 +1,23 @@
+# SPDX-License-Identifier: GPL-2.0-only
+config DCB
+	bool "Data Center Bridging support"
+	default n
+	help
+	  This enables support for configuring Data Center Bridging (DCB)
+	  features on DCB capable Ethernet adapters via rtnetlink.  Say 'Y'
+	  if you have a DCB capable Ethernet adapter which supports this
+	  interface and you are connected to a DCB capable switch.
+
+	  DCB is a collection of Ethernet enhancements which allow DCB capable
+	  NICs and switches to support network traffic with differing
+	  requirements (highly reliable, no drops vs. best effort vs. low
+	  latency) to co-exist on Ethernet.
+
+	  DCB features include:
+	    Enhanced Transmission Selection (aka Priority Grouping) - provides a
+	      framework for assigning bandwidth guarantees to traffic classes.
+	    Priority-based Flow Control (PFC) - a MAC control pause frame which
+	      works at the granularity of the 802.1p priority instead of the
+	      link (802.3x).
+
+	  If unsure, say N.