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/ufs/file.c | 48 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 48 insertions(+) create mode 100644 fs/ufs/file.c (limited to 'fs/ufs/file.c') diff --git a/fs/ufs/file.c b/fs/ufs/file.c new file mode 100644 index 000000000..85c509ced --- /dev/null +++ b/fs/ufs/file.c @@ -0,0 +1,48 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * linux/fs/ufs/file.c + * + * Copyright (C) 1998 + * Daniel Pirkl + * Charles University, Faculty of Mathematics and Physics + * + * from + * + * linux/fs/ext2/file.c + * + * Copyright (C) 1992, 1993, 1994, 1995 + * Remy Card (card@masi.ibp.fr) + * Laboratoire MASI - Institut Blaise Pascal + * Universite Pierre et Marie Curie (Paris VI) + * + * from + * + * linux/fs/minix/file.c + * + * Copyright (C) 1991, 1992 Linus Torvalds + * + * ext2 fs regular file handling primitives + */ + +#include +#include + +#include "ufs_fs.h" +#include "ufs.h" + +/* + * We have mostly NULL's here: the current defaults are ok for + * the ufs filesystem. + */ + +const struct file_operations ufs_file_operations = { + .llseek = generic_file_llseek, + .read_iter = generic_file_read_iter, + .write_iter = generic_file_write_iter, + .mmap_prepare = generic_file_mmap_prepare, + .open = generic_file_open, + .fsync = simple_fsync, + .splice_read = filemap_splice_read, + .splice_write = iter_file_splice_write, + .setlease = generic_setlease, +}; -- cgit v1.3.1