linux-kernel - pcmcia resume 60 second hang. Re: [patch 00/69] -stable review

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Message-ID: <20070524200435.GA9604@elf.ucw.cz>
Date:	Thu, 24 May 2007 22:04:35 +0200
From:	Pavel Machek <pavel@....cz>
To:	Linus Torvalds <torvalds@...ux-foundation.org>
Cc:	Romano Giannetti <romanol@...omillas.es>,
	Chris Wright <chrisw@...s-sol.org>,
	Chuck Ebbert <cebbert@...hat.com>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	stable@...nel.org, Justin Forbes <jmforbes@...uxtx.org>,
	Zwane Mwaikambo <zwane@....linux.org.uk>,
	Theodore Ts'o <tytso@....edu>,
	Randy Dunlap <rdunlap@...otime.net>,
	Dave Jones <davej@...hat.com>,
	Chuck Wolber <chuckw@...ntumlinux.com>,
	Chris Wedgwood <reviews@...cw.f00f.org>,
	Michael Krufky <mkrufky@...uxtv.org>,
	akpm@...ux-foundation.org, alan@...rguk.ukuu.org.uk,
	"Rafael J. Wysocki" <rjw@...k.pl>
Subject: pcmcia resume 60 second hang. Re: [patch 00/69] -stable review

Hi!

> Yeah, but the interesting one is this pair:
> 
>   events/0      R running     0     4      1 (L-TLB)
> 
>   sleep.sh      D 0000014F     0  5798   5789 (NOTLB)
>   Call Trace:
>    [<c01d3c01>] kobject_uevent_env+0x3a1/0x4a0
>    [<c02d8509>] wait_for_completion+0x79/0xb0
>    [<c0116640>] default_wake_function+0x0/0x10
>    [<c0238a08>] _request_firmware+0x1c8/0x310
>    [<c0238bef>] request_firmware+0xf/0x20
>    [<e0a35d5d>] pcmcia_bus_match+0x28d/0x3c0 [pcmcia]
>    [<c02864a7>] netlink_broadcast+0x1f7/0x310
>    [<c0233d74>] driver_probe_device+0x34/0xc0
>    [<c02d79ee>] klist_next+0x4e/0xa0
>    [<c0233014>] bus_for_each_drv+0x44/0x70
>    [<c0233eba>] device_attach+0x7a/0x80
>    [<c0233e00>] __device_attach+0x0/0x10
>    [<c0232f56>] bus_attach_device+0x26/0x60
>    [<c0231d06>] device_add+0x5e6/0x6e0
>    [<c01d350f>] kobject_init+0x2f/0x50
>    [<e0a360f5>] pcmcia_device_add+0x185/0x220 [pcmcia]
>    [<e0a36261>] pcmcia_card_add+0xa1/0xc0 [pcmcia]
>    [<e0913900>] ti12xx_power_hook+0x180/0x1d0 [yenta_socket]
>    [<e0a36300>] ds_event+0x80/0xb0 [pcmcia]
>    [<e0967359>] send_event+0x39/0x70 [pcmcia_core]
>    [<e09677b6>] socket_insert+0x86/0xe0 [pcmcia_core]
>    [<e0967c2b>] pcmcia_socket_dev_resume+0x7b/0x90 [pcmcia_core]
>    [<c01e135f>] pci_device_resume+0x1f/0x60
>    [<c023815f>] resume_device+0x5f/0xf0
> 
> ie we have a deadlock because resume wants to do that firmware request,
> but the event daemon is apparently spinning like mad. 
> 
> And yes, request_firmware() has a "loading_timeout" in seconds.  And
> it's 60. So that explains your pause right there!

If someone does request_firmware from resume function... that's
bad. Resume function should be fixed. Pcmcia? ti12xx driver?

> It might be some unfortunate interaction with process freezing (my
> favorite whipping boy), but it could also be something else.  I
> suspect

Well. we'd like to present hardware in working state as soon as we
resume (if eth0 was there before resume, it should be there after
resume. not 3 seconds after resume); so if someone needs to load the
firmware, they should just store it in the kernel memory, and load it
during boot or during (very early) suspend.

									Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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