netdev - Re: [PATCH net v3 3/3] tcp: Protect accesses to .ts_recent_stamp with {READ,WRITE}

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Date:   Thu, 5 Dec 2019 19:50:39 -0800
From:   Eric Dumazet <eric.dumazet@...il.com>
To:     Guillaume Nault <gnault@...hat.com>,
        David Miller <davem@...emloft.net>,
        Jakub Kicinski <jakub.kicinski@...ronome.com>
Cc:     netdev@...r.kernel.org, Eric Dumazet <edumazet@...gle.com>
Subject: Re: [PATCH net v3 3/3] tcp: Protect accesses to .ts_recent_stamp with
 {READ,WRITE}_ONCE()



On 12/5/19 5:50 PM, Guillaume Nault wrote:
> Syncookies borrow the ->rx_opt.ts_recent_stamp field to store the
> timestamp of the last synflood. Protect them with READ_ONCE() and
> WRITE_ONCE() since reads and writes aren't serialised.
> 
> Fixes: 264ea103a747 ("tcp: syncookies: extend validity range")
> Signed-off-by: Guillaume Nault <gnault@...hat.com>

Signed-off-by: Eric Dumazet <edumazet@...gle.com>

To be fair, bug was there before the patch mentioned in the Fixes: tag,
but we probably do not care enough to backport this to very old kernels.