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    SubjectRe: [PATCH] tpm/tpm_tis: Free IRQ if probing fails
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    Hi,

    On 4/13/20 8:07 PM, Jarkko Sakkinen wrote:
    > On Mon, Apr 13, 2020 at 12:04:25PM +0200, Hans de Goede wrote:
    >> Hi Jarkko,
    >>
    >> On 4/12/20 7:04 PM, Jarkko Sakkinen wrote:
    >>> Call devm_free_irq() if we have to revert to polling in order not to
    >>> unnecessarily reserve the IRQ for the life-cycle of the driver.
    >>>
    >>> Cc: stable@vger.kernel.org # 4.5.x
    >>> Reported-by: Hans de Goede <hdegoede@redhat.com>
    >>> Fixes: e3837e74a06d ("tpm_tis: Refactor the interrupt setup")
    >>> Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
    >>> ---
    >>> drivers/char/tpm/tpm_tis_core.c | 5 ++++-
    >>> 1 file changed, 4 insertions(+), 1 deletion(-)
    >>>
    >>> diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
    >>> index 27c6ca031e23..ae6868e7b696 100644
    >>> --- a/drivers/char/tpm/tpm_tis_core.c
    >>> +++ b/drivers/char/tpm/tpm_tis_core.c
    >>> @@ -1062,9 +1062,12 @@ int tpm_tis_core_init(struct device *dev, struct tpm_tis_data *priv, int irq,
    >>> if (irq) {
    >>> tpm_tis_probe_irq_single(chip, intmask, IRQF_SHARED,
    >>> irq);
    >>> - if (!(chip->flags & TPM_CHIP_FLAG_IRQ))
    >>> + if (!(chip->flags & TPM_CHIP_FLAG_IRQ)) {
    >>> dev_err(&chip->dev, FW_BUG
    >>> "TPM interrupt not working, polling instead\n");
    >>> + devm_free_irq(chip->dev.parent, priv->irq,
    >>> + chip);
    >>> + }
    >>
    >> My initial plan was actually to do something similar, but if the probe code
    >> is actually ever fixed to work as intended again then this will lead to a
    >> double free as then the IRQ-test path of tpm_tis_send() will have called
    >> disable_interrupts() which already calls devm_free_irq().
    >>
    >> You could check for chip->irq != 0 here to avoid that.
    >>
    >> But it all is rather messy, which is why I went with the "#if 0" approach
    >> in my patch.
    >
    > I think it is right way to fix it. It is a bug independent of the issue
    > we are experiencing.
    >
    > However, what you are suggesting should be done in addition. Do you have
    > a patch in place or do you want me to refine mine?

    I do not have a patch ready for this, if you can refine yours that would
    be great.

    Regards,

    Hans

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