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/timestamp.h | 124 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 124 insertions(+) create mode 100644 include/trace/events/timestamp.h (limited to 'include/trace/events/timestamp.h') diff --git a/include/trace/events/timestamp.h b/include/trace/events/timestamp.h new file mode 100644 index 000000000..d6503612d --- /dev/null +++ b/include/trace/events/timestamp.h @@ -0,0 +1,124 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#undef TRACE_SYSTEM +#define TRACE_SYSTEM timestamp + +#if !defined(_TRACE_TIMESTAMP_H) || defined(TRACE_HEADER_MULTI_READ) +#define _TRACE_TIMESTAMP_H + +#include +#include + +#define CTIME_QUERIED_FLAGS \ + { I_CTIME_QUERIED, "Q" } + +DECLARE_EVENT_CLASS(ctime, + TP_PROTO(struct inode *inode, + struct timespec64 *ctime), + + TP_ARGS(inode, ctime), + + TP_STRUCT__entry( + __field(u64, ino) + __field(time64_t, ctime_s) + __field(dev_t, dev) + __field(u32, ctime_ns) + __field(u32, gen) + ), + + TP_fast_assign( + __entry->dev = inode->i_sb->s_dev; + __entry->ino = inode->i_ino; + __entry->gen = inode->i_generation; + __entry->ctime_s = ctime->tv_sec; + __entry->ctime_ns = ctime->tv_nsec; + ), + + TP_printk("ino=%d:%d:%llu:%u ctime=%lld.%u", + MAJOR(__entry->dev), MINOR(__entry->dev), __entry->ino, __entry->gen, + __entry->ctime_s, __entry->ctime_ns + ) +); + +DEFINE_EVENT(ctime, inode_set_ctime_to_ts, + TP_PROTO(struct inode *inode, + struct timespec64 *ctime), + TP_ARGS(inode, ctime)); + +DEFINE_EVENT(ctime, ctime_xchg_skip, + TP_PROTO(struct inode *inode, + struct timespec64 *ctime), + TP_ARGS(inode, ctime)); + +TRACE_EVENT(ctime_ns_xchg, + TP_PROTO(struct inode *inode, + u32 old, + u32 new, + u32 cur), + + TP_ARGS(inode, old, new, cur), + + TP_STRUCT__entry( + __field(u64, ino) + __field(dev_t, dev) + __field(u32, gen) + __field(u32, old) + __field(u32, new) + __field(u32, cur) + ), + + TP_fast_assign( + __entry->dev = inode->i_sb->s_dev; + __entry->ino = inode->i_ino; + __entry->gen = inode->i_generation; + __entry->old = old; + __entry->new = new; + __entry->cur = cur; + ), + + TP_printk("ino=%d:%d:%llu:%u old=%u:%s new=%u cur=%u:%s", + MAJOR(__entry->dev), MINOR(__entry->dev), __entry->ino, __entry->gen, + __entry->old & ~I_CTIME_QUERIED, + __print_flags(__entry->old & I_CTIME_QUERIED, "|", CTIME_QUERIED_FLAGS), + __entry->new, + __entry->cur & ~I_CTIME_QUERIED, + __print_flags(__entry->cur & I_CTIME_QUERIED, "|", CTIME_QUERIED_FLAGS) + ) +); + +TRACE_EVENT(fill_mg_cmtime, + TP_PROTO(struct inode *inode, + struct timespec64 *ctime, + struct timespec64 *mtime), + + TP_ARGS(inode, ctime, mtime), + + TP_STRUCT__entry( + __field(u64, ino) + __field(time64_t, ctime_s) + __field(time64_t, mtime_s) + __field(dev_t, dev) + __field(u32, ctime_ns) + __field(u32, mtime_ns) + __field(u32, gen) + ), + + TP_fast_assign( + __entry->dev = inode->i_sb->s_dev; + __entry->ino = inode->i_ino; + __entry->gen = inode->i_generation; + __entry->ctime_s = ctime->tv_sec; + __entry->mtime_s = mtime->tv_sec; + __entry->ctime_ns = ctime->tv_nsec; + __entry->mtime_ns = mtime->tv_nsec; + ), + + TP_printk("ino=%d:%d:%llu:%u ctime=%lld.%u mtime=%lld.%u", + MAJOR(__entry->dev), MINOR(__entry->dev), __entry->ino, __entry->gen, + __entry->ctime_s, __entry->ctime_ns, + __entry->mtime_s, __entry->mtime_ns + ) +); +#endif /* _TRACE_TIMESTAMP_H */ + +/* This part must be outside protection */ +#include -- cgit v1.3.1