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/tools/rtla/rtla.rst | 52 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 52 insertions(+) create mode 100644 Documentation/tools/rtla/rtla.rst (limited to 'Documentation/tools/rtla/rtla.rst') diff --git a/Documentation/tools/rtla/rtla.rst b/Documentation/tools/rtla/rtla.rst new file mode 100644 index 000000000..6df1296b8 --- /dev/null +++ b/Documentation/tools/rtla/rtla.rst @@ -0,0 +1,52 @@ +========= +rtla +========= +-------------------------------- +Real-time Linux Analysis tool +-------------------------------- + +:Manual section: 1 + +SYNOPSIS +======== +**rtla** *COMMAND* [*OPTIONS*] + +DESCRIPTION +=========== +The **rtla** is a meta-tool that includes a set of commands that aims to +analyze the real-time properties of Linux. But instead of testing Linux +as a black box, **rtla** leverages kernel tracing capabilities to provide +precise information about the properties and root causes of unexpected +results. + +COMMANDS +======== +**hwnoise** + + Detect and quantify hardware-related noise. + +**osnoise** + + Gives information about the operating system noise (osnoise). + +**timerlat** + + Measures the IRQ and thread timer latency. + +OPTIONS +======= +**-h**, **--help** + + Display the help text. + +For other options, see the man page for the corresponding command. + +SEE ALSO +======== +**rtla-hwnoise**\(1), **rtla-osnoise**\(1), **rtla-timerlat**\(1) + +AUTHOR +====== +Daniel Bristot de Oliveira + +.. include:: common_appendix.txt -- cgit v1.3.1