From: Abramo Bagnara <abramo.bagnara@libero.it>
To: Jaroslav Kysela <perex@suse.cz>
Cc: Jeremy Hall <jhall@maoz.com>,
"paul@linuxaudiosystems.com" <paul@linuxaudiosystems.com>,
"alsa-devel@lists.sourceforge.net"
<alsa-devel@lists.sourceforge.net>
Subject: Re: rme9652: possible deadlock
Date: Mon, 28 Apr 2003 14:47:00 +0200 [thread overview]
Message-ID: <3EAD22C4.70309@libero.it> (raw)
In-Reply-To: <Pine.LNX.4.44.0304281418140.1603-100000@pnote.perex-int.cz>
Jaroslav Kysela ha scritto:
>>CPU1:
>>
>>read_lock(link_manager); read_lock(link_manager);
>>spin_lock(s1); spin_lock(s2);
>>if (stream_in_group) if (stream_in_group)
>> spin_lock(group); spin_lock(group); /* Waiting */
>>spin_lock(s2); /* BOOM! */
>>
>>I guess that 3rd version will be the one I propose ;-)
>
>
> Yep, it is in CVS now ;-) Except I don't use trylock...
>
> read_lock(link_manager);
> spin_lock(stream);
> ....
> if (stream_in_group) {
> spin_lock(group);
> spin_unlock(stream);
> }
> ....
> link_for_each(s) { /* note that streams are locked in defined order now */
> if (stream_in_group)
> spin_lock(s);
> }
> ....
> list_for_each(s) {
> if (stream_in_group)
> spin_unlock(s);
> }
> ....
> if (stream_in_group) {
> spin_lock(stream);
> spin_unlock(group);
> }
> ....
> spin_unlock(stream);
> read_unlock(link_manager);
CPU1: CPU2:
read_lock(link_manager); read_lock(link_manager);
spin_lock(s1); spin_lock(s2);
spin_lock(group); spin_lock(group); // waiting
spin_unlock(s1);
//inside list_for_each
spin_lock(s1);
spin_lock(s2); // BOOM!
I fear you cannot avoid trylock ;-)
--
Abramo Bagnara mailto:abramo.bagnara@libero.it
Opera Unica Phone: +39.546.656023
Via Emilia Interna, 140
48014 Castel Bolognese (RA) - Italy
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next prev parent reply other threads:[~2003-04-28 12:47 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-04-14 18:47 rme9652: possible deadlock Jeremy Hall
2003-04-22 14:16 ` Jaroslav Kysela
2003-04-22 19:22 ` Jeremy Hall
2003-04-22 19:42 ` Jaroslav Kysela
2003-04-22 22:04 ` Jeremy Hall
2003-04-23 9:51 ` Jaroslav Kysela
2003-04-23 15:06 ` Jeremy Hall
2003-04-23 19:19 ` Jaroslav Kysela
2003-04-24 10:03 ` Abramo Bagnara
2003-04-28 8:23 ` Jeremy Hall
2003-04-28 8:58 ` Abramo Bagnara
2003-04-28 9:58 ` Jaroslav Kysela
2003-04-28 10:11 ` Abramo Bagnara
2003-04-28 12:27 ` Jaroslav Kysela
2003-04-28 12:47 ` Abramo Bagnara [this message]
2003-04-28 18:16 ` Jaroslav Kysela
2003-04-28 19:15 ` Abramo Bagnara
2003-04-28 8:25 ` Jeremy Hall
2003-04-28 8:44 ` Jeremy Hall
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