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/vb2.h | 69 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 69 insertions(+) create mode 100644 include/trace/events/vb2.h (limited to 'include/trace/events/vb2.h') diff --git a/include/trace/events/vb2.h b/include/trace/events/vb2.h new file mode 100644 index 000000000..a40146dea --- /dev/null +++ b/include/trace/events/vb2.h @@ -0,0 +1,69 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#undef TRACE_SYSTEM +#define TRACE_SYSTEM vb2 + +#if !defined(_TRACE_VB2_H) || defined(TRACE_HEADER_MULTI_READ) +#define _TRACE_VB2_H + +#include +#include + +DECLARE_EVENT_CLASS(vb2_event_class, + TP_PROTO(struct vb2_queue *q, struct vb2_buffer *vb), + TP_ARGS(q, vb), + + TP_STRUCT__entry( + __field(void *, owner) + __field(u32, queued_count) + __field(int, owned_by_drv_count) + __field(u32, index) + __field(u32, type) + __field(u32, bytesused) + __field(u64, timestamp) + ), + + TP_fast_assign( + __entry->owner = q->owner; + __entry->queued_count = q->queued_count; + __entry->owned_by_drv_count = + atomic_read(&q->owned_by_drv_count); + __entry->index = vb->index; + __entry->type = vb->type; + __entry->bytesused = vb->planes[0].bytesused; + __entry->timestamp = vb->timestamp; + ), + + TP_printk("owner = %p, queued = %u, owned_by_drv = %d, index = %u, " + "type = %u, bytesused = %u, timestamp = %llu", __entry->owner, + __entry->queued_count, + __entry->owned_by_drv_count, + __entry->index, __entry->type, + __entry->bytesused, + __entry->timestamp + ) +) + +DEFINE_EVENT(vb2_event_class, vb2_buf_done, + TP_PROTO(struct vb2_queue *q, struct vb2_buffer *vb), + TP_ARGS(q, vb) +); + +DEFINE_EVENT(vb2_event_class, vb2_buf_queue, + TP_PROTO(struct vb2_queue *q, struct vb2_buffer *vb), + TP_ARGS(q, vb) +); + +DEFINE_EVENT(vb2_event_class, vb2_dqbuf, + TP_PROTO(struct vb2_queue *q, struct vb2_buffer *vb), + TP_ARGS(q, vb) +); + +DEFINE_EVENT(vb2_event_class, vb2_qbuf, + TP_PROTO(struct vb2_queue *q, struct vb2_buffer *vb), + TP_ARGS(q, vb) +); + +#endif /* if !defined(_TRACE_VB2_H) || defined(TRACE_HEADER_MULTI_READ) */ + +/* This part must be outside protection */ +#include -- cgit v1.3.1