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From: Roland Dreier on 16 Mar 2010 20:00
> ib_conn->login_buf = kmalloc(ISER_RX_LOGIN_SIZE, GFP_KERNEL);
> if (!ib_conn->login_buf) {
> - goto alloc_err;
> ret = -ENOMEM;
> + goto alloc_err;
> }

This looks like a valid fix but it's the same part of the code that Dan
found more extensive bugs in. Or, can I assume you'll sort this out and
make sure a final patch is sorted out?

Thanks,
Roland
--
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From: Roland Dreier on 31 Mar 2010 17:10
So looking at merging this finally, I think I see one problem with the
proposed patch. We have:

> @@ -183,7 +180,7 @@ static int iser_create_ib_conn_res(struct iser_conn *ib_conn)
> ib_conn->fmr_pool = ib_create_fmr_pool(device->pd, &params);
> if (IS_ERR(ib_conn->fmr_pool)) {
> ret = PTR_ERR(ib_conn->fmr_pool);
> - goto fmr_pool_err;
> + goto out_err;
> }

and

> @@ -209,12 +206,7 @@ static int iser_create_ib_conn_res(struct iser_conn *ib_conn)
> ib_conn->fmr_pool, ib_conn->cma_id->qp);
> return ret;
>
> -qp_err:
> - (void)ib_destroy_fmr_pool(ib_conn->fmr_pool);
> -fmr_pool_err:
> - kfree(ib_conn->page_vec);
> - kfree(ib_conn->login_buf);
> -alloc_err:
> +out_err:
> iser_err("unable to alloc mem or create resource, err %d\n", ret);
> return ret;
> }

so if ib_create_fmr_pool() fails, we're left with ib_conn->fmr_pool
holding an error pointer, right? But we're relying on
iser_free_ib_conn_res() to clean up after us, and that has:

if (ib_conn->fmr_pool != NULL)
ib_destroy_fmr_pool(ib_conn->fmr_pool);

so we're going to end up trying to free an error pointer, which will
probably crash.

I think.

Dan or Or, am I wrong here or do we need another iteration of this
patch? (the login_buf and page_vec changes do look correct to me, since
a failed kmalloc() will leave us with a NULL pointer that it is safe to
kfree() later)

- R.
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http://www.cisco.com/web/about/doing_business/legal/cri/index.html
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