From: "Michal Piotrowski" <michal.k.k.piotrowski@gmail.com>
To: torvalds@osdl.org
Cc: linux-kernel@vger.kernel.org
Subject: Re: [2.6.18-rc2-gabb5a5cc BUG] Lukewarm IQ detected in hotplug locking
Date: Wed, 26 Jul 2006 17:01:26 +0200 [thread overview]
Message-ID: <6bffcb0e0607260801s73cdee9avd207984712011c80@mail.gmail.com> (raw)
In-Reply-To: <6bffcb0e0607260151i6065457g6acf9f4d9b2a6d50@mail.gmail.com>
On 26/07/06, Michal Piotrowski <michal.k.k.piotrowski@gmail.com> wrote:
> Here is the bad commit
>
> aa95387774039096c11803c04011f1aa42d85758 is first bad commit
> commit aa95387774039096c11803c04011f1aa42d85758
> Author: Linus Torvalds <torvalds@macmini.osdl.org>
> Date: Sun Jul 23 12:12:16 2006 -0700
>
> cpu hotplug: simplify and hopefully fix locking
>
> The CPU hotplug locking was quite messy, with a recursive lock to
> handle the fact that both the actual up/down sequence wanted to
> protect itself from being re-entered, but the callbacks that it
> called also tended to want to protect themselves from CPU events.
>
> This splits the lock into two (one to serialize the whole hotplug
> sequence, the other to protect against the CPU present bitmaps
> changing). The latter still allows recursive usage because some
> subsystems (ondemand policy for cpufreq at least) had already gotten
> too used to the lax locking, but the locking mistakes are hopefully
> now less fundamental, and we now warn about recursive lock usage
> when we see it, in the hope that it can be fixed.
>
> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
>
> :040000 040000 9189d56fe28f6823287e9d1e79976e68074da5db
> 266b4ea87d2ac441bc02ad2c
> 4ba2c4f332c7c0ce M include
> :040000 040000 3dfe69afef86aef8e6472d6d543ba965833e201b
> bfb64b2824c1e23f0629e976
> 2526fd11b789d51e M kernel
Sorry for the noise.
The bug is fixed in latest git tree.
Regards,
Michal
--
Michal K. K. Piotrowski
LTG - Linux Testers Group
(http://www.stardust.webpages.pl/ltg/wiki/)
next prev parent reply other threads:[~2006-07-26 15:01 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-07-25 23:57 Michal Piotrowski
2006-07-26 1:14 ` Paul Jackson
2006-07-26 8:51 ` Michal Piotrowski
2006-07-26 15:01 ` Michal Piotrowski [this message]
2006-07-26 19:02 ` Arjan van de Ven
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