linux-kernel - Re: [RFC PATCH] usb: host: xhci: allow __GFP

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20190523163549.GA8692@infradead.org>
Date:   Thu, 23 May 2019 09:35:49 -0700
From:   Christoph Hellwig <hch@...radead.org>
To:     Oliver Neukum <oneukum@...e.com>
Cc:     Christoph Hellwig <hch@...radead.org>,
        Jaewon Kim <jaewon31.kim@...il.com>, linux-mm@...ck.org,
        gregkh@...uxfoundation.org, Jaewon Kim <jaewon31.kim@...sung.com>,
        m.szyprowski@...sung.com, ytk.lee@...sung.com,
        linux-kernel@...r.kernel.org, linux-usb@...r.kernel.org
Subject: Re: [RFC PATCH] usb: host: xhci: allow __GFP_FS in dma allocation

On Thu, May 23, 2019 at 02:32:09PM +0200, Oliver Neukum wrote:
> > Please switch to use memalloc_noio_save() instead.
> 
> Thinking about this again, we have a problem. We introduced
> memalloc_noio_save() in 3.10 . Hence the code should have been
> correct in v4.14. Which means that either
> 6518202970c1 "(mm/cma: remove unsupported gfp_mask
> parameter from cma_alloc()"
> is buggy, or the original issue with a delay of 2 seconds
> still exist.
> 
> Do we need to do something?

cma_alloc calls into alloc_contig_range to do the actual allocation,
which then calls current_gfp_context() to pick up the adjustments
from memalloc_noio_save and friends.  So at least in current mainline
we should be fine.