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/filemap.h | 202 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 202 insertions(+) create mode 100644 include/trace/events/filemap.h (limited to 'include/trace/events/filemap.h') diff --git a/include/trace/events/filemap.h b/include/trace/events/filemap.h new file mode 100644 index 000000000..4dcf8e9e2 --- /dev/null +++ b/include/trace/events/filemap.h @@ -0,0 +1,202 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#undef TRACE_SYSTEM +#define TRACE_SYSTEM filemap + +#if !defined(_TRACE_FILEMAP_H) || defined(TRACE_HEADER_MULTI_READ) +#define _TRACE_FILEMAP_H + +#include +#include +#include +#include +#include +#include +#include + +DECLARE_EVENT_CLASS(mm_filemap_op_page_cache, + + TP_PROTO(struct folio *folio), + + TP_ARGS(folio), + + TP_STRUCT__entry( + __field(u64, i_ino) + __field(unsigned long, pfn) + __field(unsigned long, index) + __field(dev_t, s_dev) + __field(unsigned char, order) + ), + + TP_fast_assign( + __entry->pfn = folio_pfn(folio); + __entry->i_ino = folio->mapping->host->i_ino; + __entry->index = folio->index; + if (folio->mapping->host->i_sb) + __entry->s_dev = folio->mapping->host->i_sb->s_dev; + else + __entry->s_dev = folio->mapping->host->i_rdev; + __entry->order = folio_order(folio); + ), + + TP_printk("dev %d:%d ino %llx pfn=0x%lx ofs=%lu order=%u", + MAJOR(__entry->s_dev), MINOR(__entry->s_dev), + __entry->i_ino, + __entry->pfn, + __entry->index << PAGE_SHIFT, + __entry->order) +); + +DEFINE_EVENT(mm_filemap_op_page_cache, mm_filemap_delete_from_page_cache, + TP_PROTO(struct folio *folio), + TP_ARGS(folio) + ); + +DEFINE_EVENT(mm_filemap_op_page_cache, mm_filemap_add_to_page_cache, + TP_PROTO(struct folio *folio), + TP_ARGS(folio) + ); + +DECLARE_EVENT_CLASS(mm_filemap_op_page_cache_range, + + TP_PROTO( + struct address_space *mapping, + pgoff_t index, + pgoff_t last_index + ), + + TP_ARGS(mapping, index, last_index), + + TP_STRUCT__entry( + __field(u64, i_ino) + __field(dev_t, s_dev) + __field(unsigned long, index) + __field(unsigned long, last_index) + ), + + TP_fast_assign( + __entry->i_ino = mapping->host->i_ino; + if (mapping->host->i_sb) + __entry->s_dev = + mapping->host->i_sb->s_dev; + else + __entry->s_dev = mapping->host->i_rdev; + __entry->index = index; + __entry->last_index = last_index; + ), + + TP_printk( + "dev=%d:%d ino=%llx ofs=%lld-%lld", + MAJOR(__entry->s_dev), + MINOR(__entry->s_dev), __entry->i_ino, + ((loff_t)__entry->index) << PAGE_SHIFT, + ((((loff_t)__entry->last_index + 1) << PAGE_SHIFT) - 1) + ) +); + +DEFINE_EVENT(mm_filemap_op_page_cache_range, mm_filemap_get_pages, + TP_PROTO( + struct address_space *mapping, + pgoff_t index, + pgoff_t last_index + ), + TP_ARGS(mapping, index, last_index) +); + +DEFINE_EVENT(mm_filemap_op_page_cache_range, mm_filemap_map_pages, + TP_PROTO( + struct address_space *mapping, + pgoff_t index, + pgoff_t last_index + ), + TP_ARGS(mapping, index, last_index) +); + +TRACE_EVENT(mm_filemap_fault, + TP_PROTO(struct address_space *mapping, pgoff_t index), + + TP_ARGS(mapping, index), + + TP_STRUCT__entry( + __field(u64, i_ino) + __field(dev_t, s_dev) + __field(unsigned long, index) + ), + + TP_fast_assign( + __entry->i_ino = mapping->host->i_ino; + if (mapping->host->i_sb) + __entry->s_dev = + mapping->host->i_sb->s_dev; + else + __entry->s_dev = mapping->host->i_rdev; + __entry->index = index; + ), + + TP_printk( + "dev=%d:%d ino=%llx ofs=%lld", + MAJOR(__entry->s_dev), + MINOR(__entry->s_dev), __entry->i_ino, + ((loff_t)__entry->index) << PAGE_SHIFT + ) +); + +TRACE_EVENT(filemap_set_wb_err, + TP_PROTO(struct address_space *mapping, errseq_t eseq), + + TP_ARGS(mapping, eseq), + + TP_STRUCT__entry( + __field(u64, i_ino) + __field(dev_t, s_dev) + __field(errseq_t, errseq) + ), + + TP_fast_assign( + __entry->i_ino = mapping->host->i_ino; + __entry->errseq = eseq; + if (mapping->host->i_sb) + __entry->s_dev = mapping->host->i_sb->s_dev; + else + __entry->s_dev = mapping->host->i_rdev; + ), + + TP_printk("dev=%d:%d ino=0x%llx errseq=0x%x", + MAJOR(__entry->s_dev), MINOR(__entry->s_dev), + __entry->i_ino, __entry->errseq) +); + +TRACE_EVENT(file_check_and_advance_wb_err, + TP_PROTO(struct file *file, errseq_t old), + + TP_ARGS(file, old), + + TP_STRUCT__entry( + __field(u64, i_ino) + __field(struct file *, file) + __field(dev_t, s_dev) + __field(errseq_t, old) + __field(errseq_t, new) + ), + + TP_fast_assign( + __entry->file = file; + __entry->i_ino = file->f_mapping->host->i_ino; + if (file->f_mapping->host->i_sb) + __entry->s_dev = + file->f_mapping->host->i_sb->s_dev; + else + __entry->s_dev = + file->f_mapping->host->i_rdev; + __entry->old = old; + __entry->new = file->f_wb_err; + ), + + TP_printk("file=%p dev=%d:%d ino=0x%llx old=0x%x new=0x%x", + __entry->file, MAJOR(__entry->s_dev), + MINOR(__entry->s_dev), __entry->i_ino, __entry->old, + __entry->new) +); +#endif /* _TRACE_FILEMAP_H */ + +/* This part must be outside protection */ +#include -- cgit v1.3.1