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authorKumar Kartikeya Dwivedi <memxor@gmail.com>2026-09-04 10:43:19 +0200
committerAlexei Starovoitov <ast@kernel.org>2026-09-04 07:58:36 -0700
commit6668ed271eaefaa63e686bdfbedaeb7b8e492722 (patch)
tree58e8288fead484f6755ad0815fc74c3742663761 /net/lapb/Kconfig
downloadlinux-stable-6668ed271eaefaa63e686bdfbedaeb7b8e492722.tar.gz
linux-stable-6668ed271eaefaa63e686bdfbedaeb7b8e492722.zip
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>
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+# SPDX-License-Identifier: GPL-2.0-only
+#
+# LAPB Data Link Drive
+#
+
+config LAPB
+ tristate "LAPB Data Link Driver"
+ help
+ Link Access Procedure, Balanced (LAPB) is the data link layer (i.e.
+ the lower) part of the X.25 protocol. It offers a reliable
+ connection service to exchange data frames with one other host, and
+ it is used to transport higher level protocols (mostly X.25 Packet
+ Layer, the higher part of X.25, but others are possible as well).
+ Usually, LAPB is used with specialized X.21 network cards, but Linux
+ currently supports LAPB only over Ethernet connections. If you want
+ to use LAPB connections over Ethernet, say Y here and to "LAPB over
+ Ethernet driver" below. Read
+ <file:Documentation/networking/lapb-module.rst> for technical
+ details.
+
+ To compile this driver as a module, choose M here: the
+ module will be called lapb. If unsure, say N.