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/jffs2/xattr_user.c | 41 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 41 insertions(+) create mode 100644 fs/jffs2/xattr_user.c (limited to 'fs/jffs2/xattr_user.c') diff --git a/fs/jffs2/xattr_user.c b/fs/jffs2/xattr_user.c new file mode 100644 index 000000000..f64edce49 --- /dev/null +++ b/fs/jffs2/xattr_user.c @@ -0,0 +1,41 @@ +/* + * JFFS2 -- Journalling Flash File System, Version 2. + * + * Copyright © 2006 NEC Corporation + * + * Created by KaiGai Kohei + * + * For licensing information, see the file 'LICENCE' in this directory. + * + */ + +#include +#include +#include +#include +#include +#include "nodelist.h" + +static int jffs2_user_getxattr(const struct xattr_handler *handler, + struct dentry *unused, struct inode *inode, + const char *name, void *buffer, size_t size) +{ + return do_jffs2_getxattr(inode, JFFS2_XPREFIX_USER, + name, buffer, size); +} + +static int jffs2_user_setxattr(const struct xattr_handler *handler, + struct mnt_idmap *idmap, + struct dentry *unused, struct inode *inode, + const char *name, const void *buffer, + size_t size, int flags) +{ + return do_jffs2_setxattr(inode, JFFS2_XPREFIX_USER, + name, buffer, size, flags); +} + +const struct xattr_handler jffs2_user_xattr_handler = { + .prefix = XATTR_USER_PREFIX, + .set = jffs2_user_setxattr, + .get = jffs2_user_getxattr +}; -- cgit v1.3.1