[PATCH v2 3/3] mm/vmalloc: skip vmalloc_dump_obj for non-vmalloc addresses

[Ye Liu]

From: Ye Liu <liuye at kylinos.cn>

vmalloc_dump_obj() unconditionally searches all vmap nodes even when
called with a non-vmalloc address (e.g. a slab or stack pointer from
mem_dump_obj()).  Add an is_vmalloc_or_module_addr() check at the
entry to avoid the unnecessary per-node trylock and rb-tree traversal.

Use is_vmalloc_or_module_addr() rather than is_vmalloc_addr() because
module, BPF, and execmem allocations reside in MODULES_VADDR..MODULES_END
on x86_64, arm64, and riscv -- outside VMALLOC_START..VMALLOC_END -- but
are still tracked in the same vmap_nodes rb-tree.

Signed-off-by: Ye Liu <liuye at kylinos.cn>
---
 mm/vmalloc.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 30c610f678dc..d8095b558365 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -5277,6 +5277,9 @@ bool vmalloc_dump_obj(void *object)
 	unsigned long addr;
 	unsigned long nr_pages;
 
+	if (!is_vmalloc_or_module_addr(object))
+		return false;
+
 	addr = PAGE_ALIGN_DOWN((unsigned long) object);
 
 	/*

-- 
2.25.1