From: Gilad Ben-Yossef <gilad@benyossef.com>
To: Tero Kristo <t-kristo@ti.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>,
Ard Biesheuvel <ard.biesheuvel@linaro.org>,
Eric Biggers <ebiggers@google.com>,
Linux Crypto Mailing List <linux-crypto@vger.kernel.org>,
linux-omap@vger.kernel.org, David Miller <davem@davemloft.net>,
Linux ARM <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH 09/10] crypto: add timeout to crypto_wait_req
Date: Wed, 6 Nov 2019 09:33:20 +0200 [thread overview]
Message-ID: <CAOtvUMc7pbtPAPUbEmz_MTHmB9LboQVdgG-t9tHCr=biEbFuUQ@mail.gmail.com> (raw)
In-Reply-To: <076f0bc6-ad04-9543-db02-d7c7060db036@ti.com>
On Wed, Nov 6, 2019 at 9:25 AM Tero Kristo <t-kristo@ti.com> wrote:
>
> On 06/11/2019 08:39, Gilad Ben-Yossef wrote:
> > Hi,
> >
> >
> > On Thu, Oct 17, 2019 at 3:26 PM Tero Kristo <t-kristo@ti.com> wrote:
> >>
> >> Currently crypto_wait_req waits indefinitely for an async crypto request
> >> to complete. This is bad as it can cause for example the crypto test
> >> manager to hang without any notification as to why it has happened.
> >> Instead of waiting indefinitely, add a 1 second timeout to the call,
> >> and provide a warning print if a timeout happens.
> >
> > While the incentive is clear and positive, this suggested solution
> > creates problems of its own.
> > In many (most?) cases where we are waiting here, we are waiting for a
> > DMA operation to finish from hardware.
> > Exiting while this pending DMA operation is not finished, even with a
> > proper error return value, is dangerous because
> > unless the calling code takes great care to not release the memory the
> > DMA is being done from/to, this can have disastrous effects.
> >
> > As Eric has already mentioned, one second might seem like a long time,
> > but we don't really know if it is enough.
> >
> > How about adding a second API (ig. crypto_wait_req_timeout) which
> > supports a calee specified timeout where
> > the calle knows how to correctly deal with timeout and port the
> > relevant call sites to use this?
>
> Yeah, that would work for me. I guess we could just swap the testmgr to
> use this timeout API, as it is quite clear it should timeout rather than
> wait indefinitely, and afaics, the data buffers it uses are limited
> size. It doesn't really matter for it whether the timeout is 1 second or
> 10 seconds, as long as it eventually times out.
As long as you avoid releasing the memory used on timeout, that should
work well, I think.
Gilad
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2019-11-06 7:33 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-17 12:25 [PATCH 00/10] crypto: omap fixes towards 5.5 Tero Kristo
2019-10-17 12:25 ` [PATCH 01/10] crypto: omap-sham: split up data to multiple sg elements with huge data Tero Kristo
2019-10-17 12:25 ` [PATCH 02/10] crypto: omap-sham: remove the sysfs group during driver removal Tero Kristo
2019-10-17 12:25 ` [PATCH 03/10] crypto: omap-aes: " Tero Kristo
2019-10-17 12:25 ` [PATCH 04/10] crypto: omap-des: add IV output handling Tero Kristo
2019-10-17 12:25 ` [PATCH 05/10] crypto: omap-aes: " Tero Kristo
2019-10-17 12:25 ` [PATCH 06/10] crypto: omap-sham: fix buffer handling for split test cases Tero Kristo
2019-10-17 12:25 ` [PATCH 07/10] crypto: omap-aes-gcm: fix corner case with only auth data Tero Kristo
2019-10-26 15:04 ` Ard Biesheuvel
2019-10-17 12:25 ` [PATCH 08/10] crypto: omap-sham: fix split update cases with cryptomgr tests Tero Kristo
2019-10-17 12:25 ` [PATCH 09/10] crypto: add timeout to crypto_wait_req Tero Kristo
2019-11-05 17:42 ` Eric Biggers
2019-11-06 6:39 ` Gilad Ben-Yossef
2019-11-06 7:25 ` Tero Kristo
2019-11-06 7:33 ` Gilad Ben-Yossef [this message]
2019-11-08 2:27 ` Eric Biggers
2019-11-08 7:40 ` Tero Kristo
2019-11-08 9:16 ` Herbert Xu
2019-11-08 9:22 ` Tero Kristo
2019-11-09 2:27 ` Eric Biggers
2019-11-09 5:01 ` Herbert Xu
2019-10-17 12:25 ` [PATCH 10/10] crypto: omap-aes: fixup aligned data cleanup Tero Kristo
2019-10-25 11:33 ` [PATCH 00/10] crypto: omap fixes towards 5.5 Ard Biesheuvel
2019-10-25 11:55 ` Tero Kristo
2019-10-25 11:56 ` Tero Kristo
2019-10-25 12:05 ` Ard Biesheuvel
2019-10-25 12:18 ` Tero Kristo
2019-10-26 15:06 ` Ard Biesheuvel
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to='CAOtvUMc7pbtPAPUbEmz_MTHmB9LboQVdgG-t9tHCr=biEbFuUQ@mail.gmail.com' \
--to=gilad@benyossef.com \
--cc=ard.biesheuvel@linaro.org \
--cc=davem@davemloft.net \
--cc=ebiggers@google.com \
--cc=herbert@gondor.apana.org.au \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-crypto@vger.kernel.org \
--cc=linux-omap@vger.kernel.org \
--cc=t-kristo@ti.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).