[PATCH v9 13/17] mm/debug: print vm_refcnt state when dumping the vma

Suren Baghdasaryan
2025-01-11T04:26:36Z

vm_refcnt encodes a number of useful states:
- whether vma is attached or detached
- the number of current vma readers
- presence of a vma writer
Let's include it in the vma dump.

Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
---
mm/debug.c | 12 ++++++++++++
1 file changed, 12 insertions(+)

diff --git a/mm/debug.c b/mm/debug.c
index 8d2acf432385..325d7bf22038 100644
--- a/mm/debug.c
+++ b/mm/debug.c
@@ -178,6 +178,17 @@ EXPORT_SYMBOL(dump_page);

void dump_vma(const struct vm_area_struct *vma)
{
+#ifdef CONFIG_PER_VMA_LOCK
+ pr_emerg("vma %px start %px end %px mm %px\n"
+ "prot %lx anon_vma %px vm_ops %px\n"
+ "pgoff %lx file %px private_data %px\n"
+ "flags: %#lx(%pGv) refcnt %x\n",
+ vma, (void *)vma->vm_start, (void *)vma->vm_end, vma->vm_mm,
+ (unsigned long)pgprot_val(vma->vm_page_prot),
+ vma->anon_vma, vma->vm_ops, vma->vm_pgoff,
+ vma->vm_file, vma->vm_private_data,
+ vma->vm_flags, &vma->vm_flags, refcount_read(&vma->vm_refcnt));
+#else
pr_emerg("vma %px start %px end %px mm %px\n"
"prot %lx anon_vma %px vm_ops %px\n"
"pgoff %lx file %px private_data %px\n"
@@ -187,6 +198,7 @@ void dump_vma(const struct vm_area_struct *vma)
vma->anon_vma, vma->vm_ops, vma->vm_pgoff,
vma->vm_file, vma->vm_private_data,
vma->vm_flags, &vma->vm_flags);
+#endif
}
EXPORT_SYMBOL(dump_vma);

--
2.47.1.613.gc27f4b7a9f-goog