linux-kernel - Re: [PATCH v8] tpm: Map the ACPI provided event log

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Message-ID: <87frlzzx14.wl-tiwai@suse.de>
Date: Fri, 03 Jan 2025 17:23:35 +0100
From: Takashi Iwai <tiwai@...e.de>
To: Jarkko Sakkinen <jarkko@...nel.org>
Cc: linux-integrity@...r.kernel.org,
	Peter Huewe <peterhuewe@....de>,
	Jason Gunthorpe <jgg@...pe.ca>,
	Colin Ian King <colin.i.king@...il.com>,
	Stefan Berger <stefanb@...ibm.com>,
	Andrew Morton <akpm@...l.org>,
	Seiji Munetoh <munetoh@...ibm.com>,
	Kylene Jo Hall <kjhall@...ibm.com>,
	Reiner Sailer <sailer@...ibm.com>,
	Ard Biesheuvel <ardb@...nel.org>,
	stable@...r.kernel.org,
	Andy Liang <andy.liang@....com>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v8] tpm: Map the ACPI provided event log

On Fri, 27 Dec 2024 16:39:09 +0100,
Jarkko Sakkinen 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().

It looks like that the subject doesn't match with the patch
description?

(snip)
> --- 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)
>  {
> @@ -136,10 +141,16 @@ 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;
>  
> +	ret = devm_add_action_or_reset(&chip->dev, tpm_bios_log_free, log->bios_event_log);
> +	if (ret) {
> +		log->bios_event_log = NULL;
> +		return ret;
> +	}
> +
>  	log->bios_event_log_end = log->bios_event_log + len;
>  
>  	virt = acpi_os_map_iomem(start, len);

I'm afraid that you forgot to correct the remaining devm_kfree() in
the error path of this function.

(I know it because I initially posted a similar fix in
   https://lore.kernel.org/all/20241107112054.28448-1-tiwai@suse.de/
 Your devm_add_action_or_reset() is a better choice, indeed, though
 :-)


thanks,

Takashi