Re: [patch] fs: aio fix rcu lookup

[Jeff Moyer]

Jeff Moyer <jmoyer@xxxxxxxxxx> writes:

> Jan Kara <jack@xxxxxxx> writes:
>
>>  But there's the second race I describe making it possible
>> for new IO to be created after io_destroy() has waited for all IO to
>> finish...
>
> Can't that be solved by introducing memory barriers around the accesses
> to ->dead?

Upon further consideration, I don't think so.

Given the options, I think adding the synchronize rcu to the io_destroy
path is the best way forward.  You're already waiting for a bunch of
queued I/O to finish, so there is no guarantee that you're going to
finish that call quickly.

Cheers,
Jeff
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