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/squashfs/xattr.h | 41 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 41 insertions(+) create mode 100644 fs/squashfs/xattr.h (limited to 'fs/squashfs/xattr.h') diff --git a/fs/squashfs/xattr.h b/fs/squashfs/xattr.h new file mode 100644 index 000000000..f1a463d8b --- /dev/null +++ b/fs/squashfs/xattr.h @@ -0,0 +1,41 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * Squashfs - a compressed read only filesystem for Linux + * + * Copyright (c) 2010 + * Phillip Lougher + * + * xattr.h + */ + +#ifdef CONFIG_SQUASHFS_XATTR +extern __le64 *squashfs_read_xattr_id_table(struct super_block *, u64, + u64 *, unsigned int *); +extern int squashfs_xattr_lookup(struct super_block *, unsigned int, int *, + unsigned int *, unsigned long long *); +#else +static inline __le64 *squashfs_read_xattr_id_table(struct super_block *sb, + u64 start, u64 *xattr_table_start, unsigned int *xattr_ids) +{ + struct squashfs_xattr_id_table *id_table; + + id_table = squashfs_read_table(sb, start, sizeof(*id_table)); + if (IS_ERR(id_table)) + return (__le64 *) id_table; + + *xattr_table_start = le64_to_cpu(id_table->xattr_table_start); + kfree(id_table); + + ERROR("Xattrs in filesystem, these will be ignored\n"); + return ERR_PTR(-ENOTSUPP); +} + +static inline int squashfs_xattr_lookup(struct super_block *sb, + unsigned int index, int *count, unsigned int *size, + unsigned long long *xattr) +{ + return 0; +} +#define squashfs_listxattr NULL +#define squashfs_xattr_handlers NULL +#endif -- cgit v1.3.1