[BUGS] 答复: [BUGS] BUG #14615: ReplicationOriginShmemInit Memory access cross-border

Hi Michael,

Thanks for your quickly response!

I think maybe you have a little misunderstanding with my solution.

My solution is that

      if (!found)

       {

              int                 i;

              MemSet(replication_states_ctl, 0, ReplicationOriginShmemSize());

              replication_states_ctl->tranche_id = LWLockNewTrancheId();

              replication_states_ctl->tranche.name = "ReplicationOrigins";

              replication_states_ctl->tranche.array_base =

                     &replication_states[0].lock;

              replication_states_ctl->tranche.array_stride =

                     sizeof(ReplicationState);

              //MemSet(replication_states, 0, ReplicationOriginShmemSize());

              for (i = 0; i < max_replication_slots; i++)

                     LWLockInitialize(&replication_states[i].lock,

                                                 replication_states_ctl->tranche_id);

       }

So I think it’s easier for understanding code.

What do you think?

Thanks.

Bret

发送自 Windows 10 版邮件应用

On Mon, Apr 10, 2017 at 3:26 PM,  <bret.shao@outlook.com> wrote:
> MemSet(replication_states, 0, ReplicationOriginShmemSize()); in function
> ReplicationOriginShmemInit cause cross-border,because that start address of
> the share memory allocated is replication_states_ctl, but call MemSet to
> initialize this memory start from replication_states which is variable
> states's address in struct ReplicationStateCtl.so call MemSet to set 0 with
> the total size of this share memory will cross border of this share memory.
>
> Although, this cross-border will not caused the system failure due to share
> memory allocation strategy after my analysis. but i still believe we
> shouldn't do like this.
>
> Fix suggestion:
> change to
>  MemSet(replication_states_ctl, 0, ReplicationOriginShmemSize()); then move
> to the beginning of if statement.

Yes, there is a mistake here, but I don't agree with your solution. It
seems to me that using mul_size(max_replication_slots,
sizeof(ReplicationState)) is the way to go as you would reinitialize
what has been set in tranche_id. Per se the attached.
--
Michael