Messages in this thread | | | Date | Wed, 28 May 2008 15:57:19 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH 1/1] Char: vt, make sysfs operations atomic |
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On Tue, 27 May 2008 16:48:58 -0400 Aristeu Rozanski <aris@ruivo.org> wrote:
> >> the reason for the code be the way it is is because vcs_{add,remove}_sysfs() > >> may sleep > > > > What's the point? To have races in the code but not sleep inside the semaphore? > what about fixing the code to remove the race _and_ not sleep inside the > semaphore? :) >
The patch does fix a race, by extending console_sem coverage to provide exclusion between the sysfs creation and teardown operations.
I assume - no race was identified in the changelog. Can we actually simultaneously run con_open() and con_close() against the same device? I guess it might be possible if userspace tried hard enough.
I renamed the patch to the much more accurate "vt: hold console_sem across sysfs operations" - "atomic" in the kernel context means "cannot context switch" and nothing "atomic" is happening in this patch.
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