Re: [Tarantool-patches] [PATCH 1/1] iproto: don't destroy a session during disconnect

[Vladislav Shpilevoy <v.shpilevoy@tarantool.org>]

On 16/11/2019 12:54, Konstantin Osipov wrote:
> * Vladislav Shpilevoy <v.shpilevoy@tarantool.org> [19/11/16 12:48]:
>> Binary session disconnect trigger yield could lead to use after
>> free of the session object. That happened because iproto thread
>> sent two requests to TX thread at disconnect:
>>
>>     - Close the session and run its on disconnect triggers;
>>
>>     - If all requests are handled, destroy the session.
>>
>> When a connection is idle, all requests are handled, so both these
>> requests are sent. If the first one yielded in TX thread, the
>> second one arrived and destroyed the session right under the feet
>> of the first one.
>>
>> This can be solved in two ways - in TX thread, and in iproto
>> thread.
>>
>> TX thread solution (which is chosen in the patch): add a flag
>> which says whether disconnect is processed by TX. When destroy
>> request arrives, it checks the flag. If disconnect is not done,
>> the destroy request waits on a condition variable until it is.
>>
>> The solution is simple, but adds new members to iproto_connection
>> struct, and requires lots of commenting.
>>
>> Iproto thread solution (alternative): just don't send destroy
>> request until disconnect returns back to iproto thread.
> 
> I like this one more to be honest. 
> 

Me too. Then look at v2 thread.