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From: "Rafael J. Wysocki" <rafael@kernel.org>
To: Chenyuan Mi <cymi20@fudan.edu.cn>
Cc: rafael.j.wysocki@intel.com, robert.moore@intel.com,
	linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org,
	acpica-devel@lists.linuxfoundation.org, lenb@kernel.org
Subject: Re: [Acpica-devel] [PATCH] ACPICA: Fix missing check for return value of acpi_ns_get_attached_object()
Date: Wed, 14 Jun 2023 18:40:39 +0200	[thread overview]
Message-ID: <CAJZ5v0iZMHmgGE7ZTmOghHtWPXECx5HFt2a1NBNwABBX0CQBeg@mail.gmail.com> (raw)
In-Reply-To: <20230614162112.122816-1-cymi20@fudan.edu.cn>

On Wed, Jun 14, 2023 at 6:21 PM Chenyuan Mi <cymi20@fudan.edu.cn> wrote:
>
> The acpi_ns_get_attached_object() function may return
> NULL, which may cause null pointer deference, and most
> other callsites of acpi_ns_get_attached_object() do
> Null check. Add Null check for return value of
> acpi_ns_get_attached_object().

But may acpi_ex_prep_field_value() be called in a code path where
acpi_ns_get_attached_object(i) can return NULL?

I mean, if the given attached object is guaranteed to exist when this
function is called, NULL will not be returned, so the new check will
be redundant then.

> Found by our static analysis tool.
>
> Signed-off-by: Chenyuan Mi <cymi20@fudan.edu.cn>
> ---
>  drivers/acpi/acpica/exprep.c | 7 +++++++
>  1 file changed, 7 insertions(+)
>
> diff --git a/drivers/acpi/acpica/exprep.c b/drivers/acpi/acpica/exprep.c
> index 08196fa17080..d9c006ec1ac8 100644
> --- a/drivers/acpi/acpica/exprep.c
> +++ b/drivers/acpi/acpica/exprep.c
> @@ -431,6 +431,13 @@ acpi_status acpi_ex_prep_field_value(struct acpi_create_field_info *info)
>                 obj_desc->field.region_obj =
>                     acpi_ns_get_attached_object(info->region_node);
>
> +               if (!obj_desc->field.region_obj) {
> +                       ACPI_ERROR((AE_INFO,
> +                                   "Null Region Object during field prep"));
> +                       acpi_ut_delete_object_desc(obj_desc);
> +                       return_ACPI_STATUS(AE_AML_INTERNAL);
> +               }
> +
>                 /* Fields specific to generic_serial_bus fields */
>
>                 obj_desc->field.access_length = info->access_length;
> --
> 2.17.1
>

  reply	other threads:[~2023-06-14 16:40 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-06-14 16:21 [Acpica-devel] [PATCH] ACPICA: Fix missing check for return value of acpi_ns_get_attached_object() Chenyuan Mi
2023-06-14 16:40 ` Rafael J. Wysocki [this message]
2023-06-15  7:41   ` 20210240143

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