linux-kernel - Re: [PATCH] tpm,tpm_tis: Avoid warning splat at shutdown

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Date: Fri, 02 Feb 2024 01:18:59 +0200
From: "Jarkko Sakkinen" <jarkko@...nel.org>
To: "Elliott, Robert (Servers)" <elliott@....com>, "Lino Sanfilippo"
 <l.sanfilippo@...bus.com>, "peterhuewe@....de" <peterhuewe@....de>
Cc: "LinoSanfilippo@....de" <LinoSanfilippo@....de>,
 "p.rosenberger@...bus.com" <p.rosenberger@...bus.com>, "lukas@...ner.de"
 <lukas@...ner.de>, "jgg@...pe.ca" <jgg@...pe.ca>,
 "linux-integrity@...r.kernel.org" <linux-integrity@...r.kernel.org>,
 "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
 "stable@...r.kernel.org" <stable@...r.kernel.org>
Subject: Re: [PATCH] tpm,tpm_tis: Avoid warning splat at shutdown

On Thu Feb 1, 2024 at 6:40 PM EET, Elliott, Robert (Servers) wrote:
> > From: Lino Sanfilippo <l.sanfilippo@...bus.com>
> > Sent: Thursday, February 1, 2024 5:37 AM
> > Subject: [PATCH] tpm,tpm_tis: Avoid warning splat at shutdown
> > 
> > If interrupts are not activated the work struct 'free_irq_work' is not
> > initialized. This results in a warning splat at module shutdown.
> > 
> > Fix this by always initializing the work regardless of whether interrupts
> > are activated or not.
>
> That's using flush_work(), which just waits for one to complete. Is there
> any case where multiple work entries could be queued, and cancel_work_sync() 
> would be necessary?

Questions are cool but please explain how this aligns with the patch
review because I already accepted the patch.

Should I drop it based on this question, and if so, why?

> tpm_tis_probe_irq() has a loop calling tpm_tis_probe_irq_single()
> for 3 to 15. Could each of those could trigger an interrupt storm and
> call tpm_tis_revert_interrupts(), which calls schedule_work()?

AFAIK no based on that TPM_CHIP_FLAG_IRQ should take care of this.

BR, Jarkko