Re: [PATCH v10] tpm: Map the ACPI provided event log

Ard Biesheuvel
2025-01-16T09:39:21Z

On Wed, 15 Jan 2025 at 23:55, Jarkko Sakkinen <jarkko@kernel.org> wrote:
>
> The following failure was reported:
>
> [ 10.693310][ T1] tpm_tis STM0925:00: 2.0 TPM (device-id 0x3, rev-id 0)
> [ 10.848132][ T1] ------------[ cut here ]------------
> [ 10.853559][ T1] WARNING: CPU: 59 PID: 1 at mm/page_alloc.c:4727 __alloc_pages_noprof+0x2ca/0x330
> [ 10.862827][ T1] Modules linked in:
> [ 10.866671][ T1] CPU: 59 UID: 0 PID: 1 Comm: swapper/0 Not tainted 6.12.0-lp155.2.g52785e2-default #1 openSUSE Tumbleweed (unreleased) 588cd98293a7c9eba9013378d807364c088c9375
> [ 10.882741][ T1] Hardware name: HPE ProLiant DL320 Gen12/ProLiant DL320 Gen12, BIOS 1.20 10/28/2024
> [ 10.892170][ T1] RIP: 0010:__alloc_pages_noprof+0x2ca/0x330
> [ 10.898103][ T1] Code: 24 08 e9 4a fe ff ff e8 34 36 fa ff e9 88 fe ff ff 83 fe 0a 0f 86 b3 fd ff ff 80 3d 01 e7 ce 01 00 75 09 c6 05 f8 e6 ce 01 01 <0f> 0b 45 31 ff e9 e5 fe ff ff f7 c2 00 00 08 00 75 42 89 d9 80 e1
> [ 10.917750][ T1] RSP: 0000:ffffb7cf40077980 EFLAGS: 00010246
> [ 10.923777][ T1] RAX: 0000000000000000 RBX: 0000000000040cc0 RCX: 0000000000000000
> [ 10.931727][ T1] RDX: 0000000000000000 RSI: 000000000000000c RDI: 0000000000040cc0
>
> Above shows that ACPI pointed a 16 MiB buffer for the log events because
> RSI maps to the 'order' parameter of __alloc_pages_noprof(). Address the
> bug with kvmalloc() and devm_add_action_or_reset().
>
> Suggested-by: Ard Biesheuvel <ardb@kernel.org>
> Cc: stable@vger.kernel.org # v2.6.16+
> Fixes: 55a82ab3181b ("[PATCH] tpm: add bios measurement log")
> Reported-by: Andy Liang <andy.liang@hpe.com>
> Closes: https://bugzilla.kernel.org/show_bug.cgi?id=219495
> Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>

Reviewed-by: Ard Biesheuvel <ardb@kernel.org>

> ---
> v10:
> * Had forgotten diff to staging (sorry).
> v9:
> * Call devm_add_action() as the last step and execute the plain action
> in the fallback path:
> https://lore.kernel.org/linux-integrity/87frlzzx14.wl-tiwai@suse.de/
> v8:
> * Reduced to only to this quick fix. Let HPE reserve 16 MiB if they want
> to. We have mapping approach backed up in lore.
> v7:
> * Use devm_add_action_or_reset().
> * Fix tags.
> v6:
> * A new patch.
> ---
> drivers/char/tpm/eventlog/acpi.c | 13 +++++++++++--
> 1 file changed, 11 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/char/tpm/eventlog/acpi.c b/drivers/char/tpm/eventlog/acpi.c
> index 69533d0bfb51..50770cafa835 100644
> --- a/drivers/char/tpm/eventlog/acpi.c
> +++ b/drivers/char/tpm/eventlog/acpi.c
> @@ -63,6 +63,11 @@ static bool tpm_is_tpm2_log(void *bios_event_log, u64 len)
> return n == 0;
> }
>
> +static void tpm_bios_log_free(void *data)
> +{
> + kvfree(data);
> +}
> +
> /* read binary bios log */
> int tpm_read_log_acpi(struct tpm_chip *chip)
> {
> @@ -136,7 +141,7 @@ int tpm_read_log_acpi(struct tpm_chip *chip)
> }
>
> /* malloc EventLog space */
> - log->bios_event_log = devm_kmalloc(&chip->dev, len, GFP_KERNEL);
> + log->bios_event_log = kvmalloc(len, GFP_KERNEL);
> if (!log->bios_event_log)
> return -ENOMEM;
>
> @@ -161,10 +166,14 @@ int tpm_read_log_acpi(struct tpm_chip *chip)
> goto err;
> }
>
> + ret = devm_add_action(&chip->dev, tpm_bios_log_free, log->bios_event_log);
> + if (ret)
> + goto err;
> +
> return format;
>
> err:
> - devm_kfree(&chip->dev, log->bios_event_log);
> + tpm_bios_log_free(log->bios_event_log);
> log->bios_event_log = NULL;
> return ret;
> }
> --
> 2.48.0
>