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From: Jason Gunthorpe <jgg@ziepe.ca>
To: Nelson Elhage <nelhage@nelhage.com>
Cc: linux-rdma@vger.kernel.org
Subject: Re: rdma-core: ibv_dontfork_range should not round up to page boundaries
Date: Fri, 7 Jan 2022 11:06:55 -0400	[thread overview]
Message-ID: <20220107150655.GZ6467@ziepe.ca> (raw)
In-Reply-To: <CAPSG9dZ-dkWPcbXECQeZyvOHu7M+vfrX+jJDe+fxY6_iSnQyKw@mail.gmail.com>

On Mon, Jan 03, 2022 at 10:26:32AM -0800, Nelson Elhage wrote:

> The proximate bug here is arguably in the libiverbs clients that are
> making the problematic registrations, but I'd like to see libiverbs be
> more helpful here by rejecting non-page-aligned regions, at least in
> fork-safe mode. Marking memory we don't control as `MADV_DONTFORK` is
> *always* incorrect behavior, even if most of the time it may not have
> immediate consequences.

This is a huge ABI break.
 
> I expect this change could pose compatibility problems for existing
> libraries. Potentially it could be rolled out as a warning initially,
> which would help surface the problem and correct downstreams, as well
> as making it easier for administrators to debug this problem.

This is all fixed in newer kernels and rdma-core's. Talk to your
vendors, upgrade, etc..

Jason

      reply	other threads:[~2022-01-07 15:07 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-01-03 18:26 Nelson Elhage
2022-01-07 15:06 ` Jason Gunthorpe [this message]

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