linux-kernel - Re: [PATCH] media: add GFP flag to media_*() that could get called in atomic context

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: <20160314071358.27c87dab@recife.lan>
Date:	Mon, 14 Mar 2016 07:13:58 -0300
From:	Mauro Carvalho Chehab <mchehab@....samsung.com>
To:	Sakari Ailus <sakari.ailus@....fi>
Cc:	Shuah Khan <shuahkh@....samsung.com>, kyungmin.park@...sung.com,
	a.hajda@...sung.com, s.nawrocki@...sung.com, kgene@...nel.org,
	k.kozlowski@...sung.com, laurent.pinchart@...asonboard.com,
	hyun.kwon@...inx.com, soren.brinkmann@...inx.com,
	gregkh@...uxfoundation.org, perex@...ex.cz, tiwai@...e.com,
	hans.verkuil@...co.com, lixiubo@...s.chinamobile.com,
	javier@....samsung.com, g.liakhovetski@....de,
	chehabrafael@...il.com, crope@....fi, tommi.franttila@...el.com,
	dan.carpenter@...cle.com, prabhakar.csengg@...il.com,
	hamohammed.sa@...il.com, der.herr@...r.at, navyasri.tech@...il.com,
	Julia.Lawall@...6.fr, amitoj1606@...il.com,
	linux-media@...r.kernel.org, linux-kernel@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org,
	linux-samsung-soc@...r.kernel.org,
	linux-renesas-soc@...r.kernel.org, devel@...verdev.osuosl.org,
	alsa-devel@...a-project.org
Subject: Re: [PATCH] media: add GFP flag to media_*() that could get called
 in atomic context

Em Mon, 14 Mar 2016 09:22:37 +0200
Sakari Ailus <sakari.ailus@....fi> escreveu:

> Hi Shuah,
> 
> On Sat, Mar 12, 2016 at 06:48:09PM -0700, Shuah Khan wrote:
> > Add GFP flags to media_create_pad_link(), media_create_intf_link(),
> > media_devnode_create(), and media_add_link() that could get called
> > in atomic context to allow callers to pass in the right flags for
> > memory allocation.
> > 
> > tree-wide driver changes for media_*() GFP flags change:
> > Change drivers to add gfpflags to interffaces, media_create_pad_link(),
> > media_create_intf_link() and media_devnode_create().
> > 
> > Signed-off-by: Shuah Khan <shuahkh@....samsung.com>
> > Suggested-by: Mauro Carvalho Chehab <mchehab@....samsung.com>  
> 
> What's the use case for calling the above functions in an atomic context?
> 

ALSA code seems to do a lot of stuff at atomic context. That's what
happens on my test machine when au0828 gets probed before
snd-usb-audio:
	http://pastebin.com/LEX5LD5K

It seems that ALSA USB probe routine (usb_audio_probe) happens in
atomic context.

Regards,
Mauro