Re: [RFC PATCH 1/4] security: ima: move ima_init into late_initcall_sync

[Yeoreum Yun <yeoreum.yun@arm.com>]

On Mon, Apr 20, 2026 at 11:32:56AM +0100, Jonathan McDowell wrote:
> On Fri, Apr 17, 2026 at 06:57:56PM +0100, Yeoreum Yun wrote:
> > To generate the boot_aggregate log in the IMA subsystem with TPM PCR values,
> > the TPM driver must be built as built-in and
> > must be probed before the IMA subsystem is initialized.
> >
> > However, when the TPM device operates over the FF-A protocol using
> > the CRB interface, probing fails and returns -EPROBE_DEFER if
> > the tpm_crb_ffa device — an FF-A device that provides the communication
> > interface to the tpm_crb driver — has not yet been probed.
> >
> > To ensure the TPM device operating over the FF-A protocol with
> > the CRB interface is probed before IMA initialization,
> > the following conditions must be met:
> >
> >   1. The corresponding ffa_device must be registered,
> >      which is done via ffa_init().
> >
> >   2. The tpm_crb_driver must successfully probe this device via
> >      tpm_crb_ffa_init().
> >
> >   3. The tpm_crb driver using CRB over FF-A can then
> >      be probed successfully. (See crb_acpi_add() and
> >      tpm_crb_ffa_init() for reference.)
> >
> > Unfortunately, ffa_init(), tpm_crb_ffa_init(), and crb_acpi_driver_init() are
> > all registered with device_initcall, which means crb_acpi_driver_init() may
> > be invoked before ffa_init() and tpm_crb_ffa_init() are completed.
> >
> > When this occurs, probing the TPM device is deferred.
> > However, the deferred probe can happen after the IMA subsystem
> > has already been initialized, since IMA initialization is performed
> > during late_initcall, and deferred_probe_initcall() is performed
> > at the same level.
> >
> > To resolve this, move ima_init() into late_inicall_sync level
> > so that let IMA not miss TPM PCR value when generating boot_aggregate
> > log though TPM device presents in the system.
> >
> > Signed-off-by: Yeoreum Yun <yeoreum.yun@arm.com>
>
> Awesome. This fixes the problems I saw with an SPI TPM on an NVIDIA GB200
> system and reported in
>
> https://lore.kernel.org/linux-integrity/aYXEepLhUouN5f99@earth.li/
>
> Reviewed-by: Jonathan McDowell <noodles@meta.com>
> Tested-by: Jonathan McDowell <noodles@meta.com>

Thanks!

>
> > ---
> > include/linux/lsm_hooks.h         |  2 ++
> > security/integrity/ima/ima_main.c |  2 +-
> > security/lsm_init.c               | 13 +++++++++++--
> > 3 files changed, 14 insertions(+), 3 deletions(-)
> >
> > diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
> > index d48bf0ad26f4..88fe105b7f00 100644
> > --- a/include/linux/lsm_hooks.h
> > +++ b/include/linux/lsm_hooks.h
> > @@ -166,6 +166,7 @@ enum lsm_order {
> >  * @initcall_fs: LSM callback for fs_initcall setup, optional
> >  * @initcall_device: LSM callback for device_initcall() setup, optional
> >  * @initcall_late: LSM callback for late_initcall() setup, optional
> > + * @initcall_late_sync: LSM callback for late_initcall_sync() setup, optional
> >  */
> > struct lsm_info {
> > 	const struct lsm_id *id;
> > @@ -181,6 +182,7 @@ struct lsm_info {
> > 	int (*initcall_fs)(void);
> > 	int (*initcall_device)(void);
> > 	int (*initcall_late)(void);
> > +	int (*initcall_late_sync)(void);
> > };
> >
> > #define DEFINE_LSM(lsm)							\
> > diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
> > index 1d6229b156fb..ace280fa3212 100644
> > --- a/security/integrity/ima/ima_main.c
> > +++ b/security/integrity/ima/ima_main.c
> > @@ -1320,5 +1320,5 @@ DEFINE_LSM(ima) = {
> > 	.order = LSM_ORDER_LAST,
> > 	.blobs = &ima_blob_sizes,
> > 	/* Start IMA after the TPM is available */
> > -	.initcall_late = init_ima,
> > +	.initcall_late_sync = init_ima,
> > };
> > diff --git a/security/lsm_init.c b/security/lsm_init.c
> > index 573e2a7250c4..4e5c59beb82a 100644
> > --- a/security/lsm_init.c
> > +++ b/security/lsm_init.c
> > @@ -547,13 +547,22 @@ device_initcall(security_initcall_device);
> >  * security_initcall_late - Run the LSM late initcalls
> >  */
> > static int __init security_initcall_late(void)
> > +{
> > +	return lsm_initcall(late);
> > +}
> > +late_initcall(security_initcall_late);
> > +
> > +/**
> > + * security_initcall_late_sync - Run the LSM late initcalls sync
> > + */
> > +static int __init security_initcall_late_sync(void)
> > {
> > 	int rc;
> >
> > -	rc = lsm_initcall(late);
> > +	rc = lsm_initcall(late_sync);
> > 	lsm_pr_dbg("all enabled LSMs fully activated\n");
> > 	call_blocking_lsm_notifier(LSM_STARTED_ALL, NULL);
> >
> > 	return rc;
> > }
> > -late_initcall(security_initcall_late);
> > +late_initcall_sync(security_initcall_late_sync);
> > --
> > LEVI:{C3F47F37-75D8-414A-A8BA-3980EC8A46D7}
> >
> >
>
> J.
>
> --
> ] https://www.earth.li/~noodles/ []  "Do I scare you?" "No." "Do you   [
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--
Sincerely,
Yeoreum Yun