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 --- fs/resctrl/Kconfig | 39 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 39 insertions(+) create mode 100644 fs/resctrl/Kconfig (limited to 'fs/resctrl/Kconfig') diff --git a/fs/resctrl/Kconfig b/fs/resctrl/Kconfig new file mode 100644 index 000000000..21671301b --- /dev/null +++ b/fs/resctrl/Kconfig @@ -0,0 +1,39 @@ +config RESCTRL_FS + bool "CPU Resource Control Filesystem (resctrl)" + depends on ARCH_HAS_CPU_RESCTRL + select KERNFS + select PROC_CPU_RESCTRL if PROC_FS + help + Some architectures provide hardware facilities to group tasks and + monitor and control their usage of memory system resources such as + caches and memory bandwidth. Examples of such facilities include + Intel's Resource Director Technology (Intel(R) RDT) and AMD's + Platform Quality of Service (AMD QoS). + + If your system has the necessary support and you want to be able to + assign tasks to groups and manipulate the associated resource + monitors and controls from userspace, say Y here to get a mountable + 'resctrl' filesystem that lets you do just that. + + If nothing mounts or prods the 'resctrl' filesystem, resource + controls and monitors are left in a quiescent, permissive state. + + On architectures where this can be disabled independently, it is + safe to say N. + + See for more information. + +config RESCTRL_FS_PSEUDO_LOCK + bool + depends on RESCTRL_FS + help + Software mechanism to pin data in a cache portion using + micro-architecture specific knowledge. + +config RESCTRL_RMID_DEPENDS_ON_CLOSID + bool + depends on RESCTRL_FS + help + Enabled by the architecture when the RMID values depend on the CLOSID. + This causes the CLOSID allocator to search for CLOSID with clean + RMID. -- cgit v1.3.1