Messages in this thread | | | Date | Sun, 22 Jun 2008 10:58:32 -0700 | From | Arjan van de Ven <> | Subject | Re: [PATCH] Fix open/close race in saa7134 |
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On Sun, 22 Jun 2008 19:33:37 +0200 Marcin Slusarz <marcin.slusarz@gmail.com> wrote:
> On Sun, Jun 22, 2008 at 10:05:07AM -0700, Arjan van de Ven wrote: > > > > From: Arjan van de Ven <arjan@linux.intel.com> > > Date: Sun, 22 Jun 2008 10:03:02 -0700 > > Subject: [PATCH] Fix open/close race in saa7134 > > > > The saa7134 driver uses a (non-atomic) variable in an attempt to > > only allow one opener of the device (how it deals with sending > > the fd over unix sockets I don't know). > > > > Unfortunately, the release function first decrements this variable, > > and THEN goes on to disable more of the device. This allows for > > a race where another opener of the device comes in after the > > decrement of the variable, configures the hardware just to then see > > the hardware be disabled by the rest of the release function. > > Simplier fix: > http://lkml.org/lkml/2008/6/9/308 > But I don't remember whether it was applied or not...
the patch might be simpler, but it's not fully correct... the decrement is non-atomic and not protected by any lock whatsoever.
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