From 6668ed271eaefaa63e686bdfbedaeb7b8e492722 Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi 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 Link: https://lore.kernel.org/r/20260904084325.52250-7-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- Documentation/admin-guide/sysctl/sunrpc.rst | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) create mode 100644 Documentation/admin-guide/sysctl/sunrpc.rst (limited to 'Documentation/admin-guide/sysctl/sunrpc.rst') diff --git a/Documentation/admin-guide/sysctl/sunrpc.rst b/Documentation/admin-guide/sysctl/sunrpc.rst new file mode 100644 index 000000000..09780a682 --- /dev/null +++ b/Documentation/admin-guide/sysctl/sunrpc.rst @@ -0,0 +1,25 @@ +=================================== +Documentation for /proc/sys/sunrpc/ +=================================== + +kernel version 2.2.10 + +Copyright (c) 1998, 1999, Rik van Riel + +For general info and legal blurb, please look in index.rst. + +------------------------------------------------------------------------------ + +This file contains the documentation for the sysctl files in +/proc/sys/sunrpc and is valid for Linux kernel version 2.2. + +The files in this directory can be used to (re)set the debug +flags of the SUN Remote Procedure Call (RPC) subsystem in +the Linux kernel. This stuff is used for NFS, KNFSD and +maybe a few other things as well. + +The files in there are used to control the debugging flags: +rpc_debug, nfs_debug, nfsd_debug and nlm_debug. + +These flags are for kernel hackers only. You should read the +source code in net/sunrpc/ for more information. -- cgit v1.3.1