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/smb/client/smb1debug.c | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) create mode 100644 fs/smb/client/smb1debug.c (limited to 'fs/smb/client/smb1debug.c') diff --git a/fs/smb/client/smb1debug.c b/fs/smb/client/smb1debug.c new file mode 100644 index 000000000..e2d013e75 --- /dev/null +++ b/fs/smb/client/smb1debug.c @@ -0,0 +1,25 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * + * Copyright (C) International Business Machines Corp., 2000,2005 + * + * Modified by Steve French (sfrench@us.ibm.com) + */ +#include "cifsproto.h" +#include "smb1proto.h" +#include "cifs_debug.h" + +void cifs_dump_detail(void *buf, size_t buf_len, struct TCP_Server_Info *server) +{ +#ifdef CONFIG_CIFS_DEBUG2 + struct smb_hdr *smb = buf; + + cifs_dbg(VFS, "Cmd: %d Err: 0x%x Flags: 0x%x Flgs2: 0x%x Mid: %d Pid: %d Wct: %d\n", + smb->Command, smb->Status.CifsError, smb->Flags, + smb->Flags2, smb->Mid, smb->Pid, smb->WordCount); + if (!server->ops->check_message(buf, buf_len, server->total_read, server)) { + cifs_dbg(VFS, "smb buf %p len %u\n", smb, + server->ops->calc_smb_size(smb)); + } +#endif /* CONFIG_CIFS_DEBUG2 */ +} -- cgit v1.3.1