Re: [PATCH] radix_tree_tag_get() is not as safe as the docs make out
From: David Howells
Date: Tue Apr 06 2010 - 17:19:26 EST
Nick Piggin <npiggin@xxxxxxx> wrote:
> Nack, just drop the BUG_ON.
I can do that.
> I don't know what you mean by "untrustworthy answer".
I was thinking that the answer you get from radix_tree_tag_get() may be invalid
if the tag chain is being modified as you read it. So if you do:
x = radix_tree_tag_get(r, i, t);
y = radix_tree_tag_get(r, i, t);
Then you can't guarantee that x == y, even though you were holding the RCU read
As you suggested, I'll try and come up with a comment modification to this
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