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/pstore/internal.h | 54 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 54 insertions(+) create mode 100644 fs/pstore/internal.h (limited to 'fs/pstore/internal.h') diff --git a/fs/pstore/internal.h b/fs/pstore/internal.h new file mode 100644 index 000000000..079284120 --- /dev/null +++ b/fs/pstore/internal.h @@ -0,0 +1,54 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __PSTORE_INTERNAL_H__ +#define __PSTORE_INTERNAL_H__ + +#include +#include +#include + +extern unsigned int kmsg_bytes; + +#ifdef CONFIG_PSTORE_FTRACE +extern unsigned long decode_ip(unsigned long ip); +extern void pstore_register_ftrace(void); +extern void pstore_unregister_ftrace(void); +ssize_t pstore_ftrace_combine_log(char **dest_log, size_t *dest_log_size, + const char *src_log, size_t src_log_size); +#else +static inline void pstore_register_ftrace(void) {} +static inline void pstore_unregister_ftrace(void) {} +static inline unsigned long decode_ip(unsigned long ip) { return ip; } +static inline ssize_t +pstore_ftrace_combine_log(char **dest_log, size_t *dest_log_size, + const char *src_log, size_t src_log_size) +{ + *dest_log_size = 0; + return 0; +} +#endif + +#ifdef CONFIG_PSTORE_PMSG +extern void pstore_register_pmsg(void); +extern void pstore_unregister_pmsg(void); +#else +static inline void pstore_register_pmsg(void) {} +static inline void pstore_unregister_pmsg(void) {} +#endif + +extern struct pstore_info *psinfo; + +extern void pstore_set_kmsg_bytes(unsigned int bytes); +extern void pstore_get_records(int); +extern void pstore_get_backend_records(struct pstore_info *psi, + struct dentry *root, int quiet); +extern int pstore_put_backend_records(struct pstore_info *psi); +extern int pstore_mkfile(struct dentry *root, + struct pstore_record *record); +extern void pstore_record_init(struct pstore_record *record, + struct pstore_info *psi); + +/* Called during pstore init/exit. */ +int __init pstore_init_fs(void); +void __exit pstore_exit_fs(void); + +#endif -- cgit v1.3.1