Thread (32 messages) 32 messages, 5 authors, 2016-04-01

Re: [PATCH net 4/4] tcp: various missing rcu_read_lock around __sk_dst_get

From: Hannes Frederic Sowa <hidden>
Date: 2016-04-01 04:12:54

On 01.04.2016 06:04, Alexei Starovoitov wrote:
On Thu, Mar 31, 2016 at 08:03:38PM -0700, Eric Dumazet wrote:
quoted
On Thu, 2016-03-31 at 18:45 -0700, Alexei Starovoitov wrote:
quoted
Eric, what's your take on Hannes's patch 2 ?
Is it more accurate to ask lockdep to check for actual lock
or lockdep can rely on owned flag?
Potentially there could be races between setting the flag and
actual lock... but that code is contained, so unlikely.
Will we find the real issues with this 'stronger' check or
just spend a ton of time adapting to new model like your other
patch for release_sock and whatever may need to come next...
More precise lockdep checks are certainly good, I only objected to 4/4
trying to work around another bug.

But why do we rush for 'net' tree ?

This looks net-next material to me.

Locking changes are often subtle, lets take the time to do them
properly.
completely agree. I think only first patch belongs in net.
Everything else is net-next material.
Problem with first patch is that it uses lock_sock_fast, thus the 
current sock_owned_by_user check doesn't get rid the lockdep warning. :/

Thus we would need to go with the two first patches. Do you think it is 
acceptable? I actually didn't see a problem and testing showed no 
problems so far.

Bye,
Hannes
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