Re: [PATCH net] nfc: avoid potential race condition
From: Jakub Kicinski <kuba@kernel.org>
Date: 2021-09-24 20:14:44
Also in:
kernel-janitors
On Fri, 24 Sep 2021 10:21:33 +0200 Krzysztof Kozlowski wrote:
On 23/09/2021 14:22, Dan Carpenter wrote:quoted
On Thu, Sep 23, 2021 at 09:26:51AM +0200, Krzysztof Kozlowski wrote:quoted
On 23/09/2021 08:50, Dan Carpenter wrote:[...]quoted
quoted
I think the difference between this llcp_sock code and above transport, is lack of writer to llcp_sock->local with whom you could race. Commits c0cfa2d8a788fcf4 and 6a2c0962105ae8ce causing the multi-transport race show nicely assigns to vsk->transport when module is unloaded. Here however there is no writer to llcp_sock->local, except bind and connect and their error paths. The readers which you modify here, have to happen after bind/connect. You cannot have getsockopt() or release() before bind/connect, can you? Unless you mean here the bind error path, where someone calls getsockopt() in the middle of bind()? Is it even possible?I don't know if this is a real issue either. Racing with bind would be harmless. The local pointer would be NULL and it would return harmlessly. You would have to race with release and have a third trying to release local devices. (Again that might be wild imagination. It may not be possible).Indeed. The code looks reasonable, though, so even if race is not really reproducible: Reviewed-by: Krzysztof Kozlowski <redacted>
Would you mind making a call if this is net (which will mean stable) or net-next material (without the Fixes tags) and reposting? Thanks! :)