Mathieu Desnoyers wrote:
----- Original Message -----
From: "Keir Fraser"<[email protected]>
To: [email protected]
Cc: "Mathieu Desnoyers"<[email protected]>, "Paul E.
McKenney"<[email protected]>
Sent: Friday, April 18, 2014 4:12:49 PM
Subject: [PATCH liburcu] Fix lifetime of rcu_barrier()'s completion structure
[Another attachment, I must sort out to integrate with git send-mail]
rcu_barrier() can return as soon as completion.barrier_count==0, which
frees the completion struct along with the rest of its stack frame. But
its call_rcu callbacks may yet try to read and write completion.futex
via the wake_up function.
Fix this by calloc()ing the completion struct and implementing a
reference count to determine when it is eventually free()d.
This also fixes bug #787, since calloc() initialises all fields of the
structure to zero.
I slightly edited your patch to use urcu_ref() and uatomic_sub_return()
(simple style fix). Please let me know if you are OK with the attached
patch.
Yes that's better, in particular I don't know how I missed the existence
of uatomic_sub_return(). Very happy with that, thanks.
-- Keir
Thanks!
Mathieu
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