ACK: [PATCH v2 7/8] ACPICA: AML Parser: ignore dispatcher error status during table load

[Tyler Hicks]

On 2019-03-29 15:37:31, Aaron Ma wrote:
> From: "Schmauss, Erik" <erik.schmauss at intel.com>
> 
> BugLink: https://bugs.launchpad.net/bugs/1820153
> 
> The dispatcher and the executer process the parse nodes During table
> load. Error status from the evaluation confuses the AML parser. This
> results in the parser failing to complete parsing of the current
> scope op which becomes problematic. For the incorrect AML below, _ADR
> never gets created.
> 
> definition_block(...)
> {
>    Scope (\_SB)
>    {
>      Device (PCI0){...}
>      Name (OBJ1, 0x0)
>      OBJ1 = PCI0 + 5 // Results in an operand error.
>    } // \_SB not closed
> 
>    // parser looks for \_SB._SB.PCI0, results in AE_NOT_FOUND error
>    // Entire scope block gets skipped.
>    Scope (\_SB.PCI0)
>    {
>        Name (_ADR, 0x0)
>    }
> }
> 
> Fix the above error by properly completing the initial \_SB scope
> after an error by clearing errors that occur during table load. In
> the above case, this means that OBJ1 = PIC0 + 5 is skipped.
> 
> Fixes: 5088814a6e93 (ACPICA: AML parser: attempt to continue loading table after error)
> Link: https://bugzilla.kernel.org/show_bug.cgi?id=200363
> Tested-by: Bastien Nocera <hadess at hadess.net>
> Signed-off-by: Erik Schmauss <erik.schmauss at intel.com>
> Cc: 4.17+ <stable at vger.kernel.org> # 4.17+
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki at intel.com>
> (cherry picked from commit 73c2a01c52b657f4a0ead6c95f64c5279efbd000)
> Signed-off-by: Aaron Ma <aaron.ma at canonical.com>

Acked-by: Tyler Hicks <tyhicks at canonical.com>

Tyler

> ---
>  drivers/acpi/acpica/psloop.c | 26 ++++++++++++++++++++++++++
>  1 file changed, 26 insertions(+)
> 
> diff --git a/drivers/acpi/acpica/psloop.c b/drivers/acpi/acpica/psloop.c
> index f437c3d54086..a5f35ff54510 100644
> --- a/drivers/acpi/acpica/psloop.c
> +++ b/drivers/acpi/acpica/psloop.c
> @@ -513,6 +513,18 @@ acpi_status acpi_ps_parse_loop(struct acpi_walk_state *walk_state)
>  			status =
>  			    acpi_ps_create_op(walk_state, aml_op_start, &op);
>  			if (ACPI_FAILURE(status)) {
> +				/*
> +				 * ACPI_PARSE_MODULE_LEVEL means that we are loading a table by
> +				 * executing it as a control method. However, if we encounter
> +				 * an error while loading the table, we need to keep trying to
> +				 * load the table rather than aborting the table load. Set the
> +				 * status to AE_OK to proceed with the table load.
> +				 */
> +				if ((walk_state->
> +				     parse_flags & ACPI_PARSE_MODULE_LEVEL)
> +				    && status == AE_ALREADY_EXISTS) {
> +					status = AE_OK;
> +				}
>  				if (status == AE_CTRL_PARSE_CONTINUE) {
>  					continue;
>  				}
> @@ -710,6 +722,20 @@ acpi_status acpi_ps_parse_loop(struct acpi_walk_state *walk_state)
>  			    acpi_ps_next_parse_state(walk_state, op, status);
>  			if (status == AE_CTRL_PENDING) {
>  				status = AE_OK;
> +			} else
> +			    if ((walk_state->
> +				 parse_flags & ACPI_PARSE_MODULE_LEVEL)
> +				&& ACPI_FAILURE(status)) {
> +				/*
> +				 * ACPI_PARSE_MODULE_LEVEL means that we are loading a table by
> +				 * executing it as a control method. However, if we encounter
> +				 * an error while loading the table, we need to keep trying to
> +				 * load the table rather than aborting the table load. Set the
> +				 * status to AE_OK to proceed with the table load. If we get a
> +				 * failure at this point, it means that the dispatcher got an
> +				 * error while processing Op (most likely an AML operand error.
> +				 */
> +				status = AE_OK;
>  			}
>  		}
>  
> -- 
> 2.17.1
> 
> 
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