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 --- include/trace/events/fsnotify.h | 51 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 51 insertions(+) create mode 100644 include/trace/events/fsnotify.h (limited to 'include/trace/events/fsnotify.h') diff --git a/include/trace/events/fsnotify.h b/include/trace/events/fsnotify.h new file mode 100644 index 000000000..341bbd57a --- /dev/null +++ b/include/trace/events/fsnotify.h @@ -0,0 +1,51 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#undef TRACE_SYSTEM +#define TRACE_SYSTEM fsnotify + +#if !defined(_TRACE_FSNOTIFY_H) || defined(TRACE_HEADER_MULTI_READ) +#define _TRACE_FSNOTIFY_H + +#include + +#include + +TRACE_EVENT(fsnotify, + TP_PROTO(__u32 mask, const void *data, int data_type, + struct inode *dir, const struct qstr *file_name, + struct inode *inode, u32 cookie), + + TP_ARGS(mask, data, data_type, dir, file_name, inode, cookie), + + TP_STRUCT__entry( + __field(__u32, mask) + __field(unsigned long, dir_ino) + __field(unsigned long, ino) + __field(dev_t, s_dev) + __field(int, data_type) + __field(u32, cookie) + __string(file_name, file_name ? (const char *)file_name->name : "") + ), + + TP_fast_assign( + __entry->mask = mask; + __entry->dir_ino = dir ? dir->i_ino : 0; + __entry->ino = inode ? inode->i_ino : 0; + __entry->s_dev = dir ? dir->i_sb->s_dev : + inode ? inode->i_sb->s_dev : 0; + __entry->data_type = data_type; + __entry->cookie = cookie; + __assign_str(file_name); + ), + + TP_printk("dev=%d:%d dir=%lu ino=%lu data_type=%d cookie=0x%x mask=0x%x %s name=%s", + MAJOR(__entry->s_dev), MINOR(__entry->s_dev), + __entry->dir_ino, __entry->ino, + __entry->data_type, __entry->cookie, + __entry->mask, show_fsnotify_mask(__entry->mask), + __get_str(file_name)) +); + +#endif /* _TRACE_FSNOTIFY_H */ + +/* This part must be outside protection */ +#include -- cgit v1.3.1