linux-kernel - Re: [PATCH v3 1/5] ACPICA: Namespace: Fix a regression that MLC support triggers dead lock in dynamic table loading

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Message-ID: <20160620105701.GI1739@lahna.fi.intel.com>
Date:	Mon, 20 Jun 2016 13:57:01 +0300
From:	Mika Westerberg <mika.westerberg@...ux.intel.com>
To:	Lv Zheng <lv.zheng@...el.com>
Cc:	"Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
	"Rafael J. Wysocki" <rjw@...ysocki.net>,
	Len Brown <len.brown@...el.com>, Lv Zheng <zetalog@...il.com>,
	linux-kernel@...r.kernel.org, linux-acpi@...r.kernel.org
Subject: Re: [PATCH v3 1/5] ACPICA: Namespace: Fix a regression that MLC
 support triggers dead lock in dynamic table loading

On Mon, Jun 20, 2016 at 05:07:22PM +0800, Lv Zheng wrote:
> The new MLC approach invokes MLC per-table basis. But the dynamic loading
> support of this is incorrect because of the lock order:
>  acpi_ns_evaluate
>    acpi_ex_enter_intperter
>      acpi_ns_load_table (triggered by Load opcode)
>        acpi_ns_exec_module_code_list
>          acpi_ex_enter_intperter
> The regression is introduced by the following commit:
>   Commit: 2785ce8d0da1cac9d8f78615e116cf929e9a9123
>   ACPICA Commit: 071eff738c59eda1792ac24b3b688b61691d7e7c
>   Subject: ACPICA: Add per-table execution of module-level code
> This patch fixes this regression by unlocking the interpreter lock before
> invoking MLC. However the unlocking is done to the acpi_ns_load_table(), in
> which, the interpreter lock should be locked by acpi_ns_parse_table() but
> wasn't. Reported by Mika Westerberg. Fixed by Lv Zheng.
> 
> Fixes: 2785ce8d0da1 ("ACPICA: Add per-table execution of module-level code")
> Reported-by: Mika Westerberg <mika.westerberg@...ux.intel.com>
> Signed-off-by: Lv Zheng <lv.zheng@...el.com>
> ---
>  drivers/acpi/acpica/exconfig.c |    2 ++
>  drivers/acpi/acpica/nsparse.c  |    8 ++++++--
>  2 files changed, 8 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/acpi/acpica/exconfig.c b/drivers/acpi/acpica/exconfig.c
> index a1d177d..21932d6 100644
> --- a/drivers/acpi/acpica/exconfig.c
> +++ b/drivers/acpi/acpica/exconfig.c
> @@ -108,7 +108,9 @@ acpi_ex_add_table(u32 table_index,
>  
>  	/* Add the table to the namespace */
>  
> +	acpi_ex_exit_interpreter();
>  	status = acpi_ns_load_table(table_index, parent_node);
> +	acpi_ex_enter_interpreter();
>  	if (ACPI_FAILURE(status)) {
>  		acpi_ut_remove_reference(obj_desc);
>  		*ddb_handle = NULL;
> diff --git a/drivers/acpi/acpica/nsparse.c b/drivers/acpi/acpica/nsparse.c
> index f631a47..0d29383 100644
> --- a/drivers/acpi/acpica/nsparse.c
> +++ b/drivers/acpi/acpica/nsparse.c
> @@ -170,6 +170,8 @@ acpi_ns_parse_table(u32 table_index, struct acpi_namespace_node *start_node)
>  
>  	ACPI_FUNCTION_TRACE(ns_parse_table);
>  
> +	acpi_ex_enter_interpreter();

I'm getting these:

drivers/acpi/acpica/nsparse.c: In function ‘acpi_ns_parse_table’:
drivers/acpi/acpica/nsparse.c:173:2: error: implicit declaration of function ‘acpi_ex_enter_interpreter’ [-Werror=implicit-function-declaration]
  acpi_ex_enter_interpreter();
  ^
drivers/acpi/acpica/nsparse.c:210:2: error: implicit declaration of function ‘acpi_ex_exit_interpreter’ [-Werror=implicit-function-declaration]
  acpi_ex_exit_interpreter();
  ^
cc1: some warnings being treated as errors

Do I need to have some other patch applied before this?