quoted

quoted

@@ -2497,6 +2533,9 @@ void *__vmalloc_node_range(unsigned long size, unsigned long align,
 	if (!addr)
 		return NULL;
 
+	if (kasan_populate_vmalloc(real_size, area))
+		return NULL;
+

KASAN itself uses __vmalloc_node_range() to allocate and map shadow in memory online callback.
So we should either skip non-vmalloc and non-module addresses here or teach kasan's memory online/offline
callbacks to not use __vmalloc_node_range() (do something similar to kasan_populate_vmalloc() perhaps?). 

Ah, right you are. I haven't been testing that.

I am a bit nervous about further restricting kasan_populate_vmalloc: I
seem to remember having problems with code using the vmalloc family of
functions to map memory that doesn't lie within vmalloc space but which
still has instrumented accesses.

I was wrong or remembering early implementation bugs.

If the memory we're allocating in __vmalloc_node_range falls outside of
vmalloc and module space, it shouldn't be getting shadow mapped for it
by kasan_populate_vmalloc. For v9, I've guarded the call with
is_vmalloc_or_module. It seems to work fine when tested with hotplugged
memory.

Thanks again.

Regards,
Daniel

On the other hand, I'm not keen on rewriting any of the memory
on/offline code if I can avoid it!

I'll have a look and get back you as soon as I can.

Thanks for catching this.

Kind regards,
Daniel

quoted

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