Messages in this thread | | | Date | Mon, 16 Jan 2023 13:44:19 +0200 | From | Jarkko Sakkinen <> | Subject | Re: [PATCH v2] tpm: Allow system suspend to continue when TPM suspend fails |
| |
On Fri, Jan 06, 2023 at 04:01:56AM +0100, Jason A. Donenfeld wrote: > TPM 1 is sometimes broken across system suspends, due to races or > locking issues or something else that haven't been diagnosed or fixed > yet, most likely having to do with concurrent reads from the TPM's > hardware random number generator driver. These issues prevent the system > from actually suspending, with errors like: > > tpm tpm0: A TPM error (28) occurred continue selftest > ...
<REMOVE>
> tpm tpm0: A TPM error (28) occurred attempting get random > ... > tpm tpm0: Error (28) sending savestate before suspend > tpm_tis 00:08: PM: __pnp_bus_suspend(): tpm_pm_suspend+0x0/0x80 returns 28 > tpm_tis 00:08: PM: dpm_run_callback(): pnp_bus_suspend+0x0/0x10 returns 28 > tpm_tis 00:08: PM: failed to suspend: error 28 > PM: Some devices failed to suspend, or early wake event detected
</REMOVE>
Unrelated to thix particular fix.
> This issue was partially fixed by 23393c646142 ("char: tpm: Protect > tpm_pm_suspend with locks"), in a last minute 6.1 commit that Linus took > directly because the TPM maintainers weren't available. However, it > seems like this just addresses the most common cases of the bug, rather > than addressing it entirely. So there are more things to fix still, > apparently. > > In lieu of actually fixing the underlying bug, just allow system suspend > to continue, so that laptops still go to sleep fine. Later, this can be > reverted when the real bug is fixed. > > Link: https://lore.kernel.org/lkml/7cbe96cf-e0b5-ba63-d1b4-f63d2e826efa@suse.cz/ > Cc: stable@vger.kernel.org # 6.1+ > Reported-by: Vlastimil Babka <vbabka@suse.cz> > Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> > Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> > --- > This is basically untested and I haven't worked out if there are any > awful implications of letting the system sleep when TPM suspend fails. > Maybe some PCRs get cleared and that will make everything explode on > resume? Maybe it doesn't matter? Somebody well versed in TPMology should > probably [n]ack this approach. > > drivers/char/tpm/tpm-interface.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c > index d69905233aff..6df9067ef7f9 100644 > --- a/drivers/char/tpm/tpm-interface.c > +++ b/drivers/char/tpm/tpm-interface.c > @@ -412,7 +412,10 @@ int tpm_pm_suspend(struct device *dev) > } > > suspended: > - return rc; > + if (rc) > + pr_err("Unable to suspend tpm-%d (error %d), but continuing system suspend\n", > + chip->dev_num, rc); > + return 0; > } > EXPORT_SYMBOL_GPL(tpm_pm_suspend); > > -- > 2.39.0 >
This tpm_tis local issue, nothing to do with tpm_pm_suspend(). Executing the selftest as part of wake up, is TPM 1.2 dTPM specific requirement, and the call is located in tpm_tis_resume() [*].
[*] https://lore.kernel.org/lkml/Y8U1QxA4GYvPWDky@kernel.org/
BR, Jarkko
| |