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/ntfs/sysctl.c | 54 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 54 insertions(+) create mode 100644 fs/ntfs/sysctl.c (limited to 'fs/ntfs/sysctl.c') diff --git a/fs/ntfs/sysctl.c b/fs/ntfs/sysctl.c new file mode 100644 index 000000000..8c5c1b7cd --- /dev/null +++ b/fs/ntfs/sysctl.c @@ -0,0 +1,54 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Code for sysctl handling in NTFS Linux kernel driver. + * + * Copyright (C) 1997 Martin von Löwis, Régis Duchesne + * Copyright (c) 2002-2005 Anton Altaparmakov + */ + +#ifdef DEBUG + +#include + +#ifdef CONFIG_SYSCTL + +#include +#include + +#include "sysctl.h" +#include "debug.h" + +/* Definition of the ntfs sysctl. */ +static const struct ctl_table ntfs_sysctls[] = { + { + .procname = "ntfs-debug", + .data = &debug_msgs, /* Data pointer and size. */ + .maxlen = sizeof(debug_msgs), + .mode = 0644, /* Mode, proc handler. */ + .proc_handler = proc_dointvec + }, +}; + +/* Storage for the sysctls header. */ +static struct ctl_table_header *sysctls_root_table; + +/* + * ntfs_sysctl - add or remove the debug sysctl + * @add: add (1) or remove (0) the sysctl + * + * Add or remove the debug sysctl. Return 0 on success or -errno on error. + */ +int ntfs_sysctl(int add) +{ + if (add) { + sysctls_root_table = register_sysctl("fs/ntfs", ntfs_sysctls); + if (!sysctls_root_table) + return -ENOMEM; + } else { + unregister_sysctl_table(sysctls_root_table); + sysctls_root_table = NULL; + } + return 0; +} +#endif /* CONFIG_SYSCTL */ +#endif /* DEBUG */ -- cgit v1.3.1