On Mon, Oct 03, 2016 at 03:48:36PM +0300, Jarkko Sakkinen wrote: > On Mon, Oct 03, 2016 at 07:05:48AM +0000, Winkler, Tomas wrote: > > > > > 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.wink...@intel.com> > > > > > > > > > > Tested-by: Jarkko Sakkinen <jarkko.sakki...@linux.intel.com> > > > > > Reviewed-by: Jarkko Sakkinen <jarkko.sakki...@linux.intel.com> > > > > > > > > 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. > > Make the driver uncallable first. The worst race that can happen is that > open("/dev/tpm0", ...) returns -EPIPE. I do not consider this fatal at > all.
No responses for this reasonable proposal so I'll show what I mean: /* Make the driver uncallable. */ down_write(&chip->ops_sem); if (chip->flags & TPM_CHIP_FLAG_TPM2) tpm2_shutdown(chip, TPM2_SU_CLEAR); chip->ops = NULL; up_write(&chip->ops_sem); cdev_del(&chip->cdev); device_del(&chip->dev); /* Make the chip unavailable. */ mutex_lock(&idr_lock); idr_replace(&dev_nums_idr, NULL, chip->dev_num); mutex_unlock(&idr_lock); The worst thing that can happen is -EPIPE. /Jarkko ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, SlashDot.org! http://sdm.link/slashdot _______________________________________________ tpmdd-devel mailing list tpmdd-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/tpmdd-devel