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/bfs/Kconfig | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) create mode 100644 fs/bfs/Kconfig (limited to 'fs/bfs/Kconfig') diff --git a/fs/bfs/Kconfig b/fs/bfs/Kconfig new file mode 100644 index 000000000..8e7ef866b --- /dev/null +++ b/fs/bfs/Kconfig @@ -0,0 +1,21 @@ +# SPDX-License-Identifier: GPL-2.0-only +config BFS_FS + tristate "BFS file system support" + depends on BLOCK + select BUFFER_HEAD + help + Boot File System (BFS) is a file system used under SCO UnixWare to + allow the bootloader access to the kernel image and other important + files during the boot process. It is usually mounted under /stand + and corresponds to the slice marked as "STAND" in the UnixWare + partition. You should say Y if you want to read or write the files + on your /stand slice from within Linux. You then also need to say Y + to "UnixWare slices support", below. More information about the BFS + file system is contained in the file + . + + If you don't know what this is about, say N. + + To compile this as a module, choose M here: the module will be called + bfs. Note that the file system of your root partition (the one + containing the directory /) cannot be compiled as a module. -- cgit v1.3.1