RE: [PATCH] tpm: don't destroy chip device prematurely
From: Winkler, Tomas
Date: Mon Oct 03 2016 - 03:39:01 EST
> > On Sun, Oct 02, 2016 at 01:24:55PM +0300, Jarkko Sakkinen wrote:
> > > On Sun, Oct 02, 2016 at 01:17:55PM +0300, Jarkko Sakkinen wrote:
> > > > On Sun, Oct 02, 2016 at 10:39:31AM +0300, Tomas Winkler wrote:
> > > > > In tpm_del_char_device device_del is called prior to
> > > > > tpm2_shutdown where it is still used.
> > > > >
> > > > > Fortunately, so far chip->dev was used only for printouts int
> > > > > tpm2_shutdown flow, hence system didn't crash. But with the
> > > > > introduction of runtime power management it will result in
> > > > > shutting down the parent device while it still in use.
> > > > >
> > > > > Fixes: 20e0152393b41 ("tpm: fix crash in tpm_tis
> > > > > deinitialization")
> > > > > Signed-off-by: Tomas Winkler <tomas.winkler@xxxxxxxxx>
> > > >
> > > > Tested-by: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx>
> > > > Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx>
> > >
> > > Applied.
> > This patch is wrong, I though the comments were clear. All entry
> > points to find the device must be deleted before we commit to shutting
> down the device.
> > You need to figure out some other way to solve your problem.
> Please be more specific regarding flows you think will be wrong with this
> patch, you must agree that the current code is broken even w/o runtime pm.
I've looked to the registration code and it indeed has few more issues
Maybe TPM_CHIP_FLAG_REGISTERED can be used for sealing the access to the device during deregistration, current usage is void.
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