Patch "ACPICA: Namespace: Fix deadlock triggered by MLC support in dynamic table loading ACPICA: Add per-table execution of module-level code" has been added to the 4.6-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    ACPICA: Namespace: Fix deadlock triggered by MLC support in dynamic table loading
  ACPICA: Add per-table execution of module-level code

to the 4.6-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     acpica-namespace-fix-deadlock-triggered-by-mlc-support-in-dynamic-table-loading.patch
and it can be found in the queue-4.6 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 2f38b1b16d9280689e5cfa47a4c50956bf437f0d Mon Sep 17 00:00:00 2001
From: Lv Zheng <lv.zheng@intel.com>
Date: Tue, 21 Jun 2016 12:34:15 +0800
Subject: ACPICA: Namespace: Fix deadlock triggered by MLC support in dynamic table loading

From: Lv Zheng <lv.zheng@intel.com>

commit 2f38b1b16d9280689e5cfa47a4c50956bf437f0d upstream.

The new module-level code (MLC) approach invokes MLC on the 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 it wasn't.

Fixes: 2785ce8d0da1 (ACPICA: Add per-table execution of module-level code)
Reported-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
[ rjw : Subject ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/acpi/acpica/exconfig.c |    2 ++
 drivers/acpi/acpica/nsparse.c  |    9 +++++++--
 2 files changed, 9 insertions(+), 2 deletions(-)

--- 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;
--- a/drivers/acpi/acpica/nsparse.c
+++ b/drivers/acpi/acpica/nsparse.c
@@ -47,6 +47,7 @@
 #include "acparser.h"
 #include "acdispat.h"
 #include "actables.h"
+#include "acinterp.h"
 
 #define _COMPONENT          ACPI_NAMESPACE
 ACPI_MODULE_NAME("nsparse")
@@ -170,6 +171,8 @@ acpi_ns_parse_table(u32 table_index, str
 
 	ACPI_FUNCTION_TRACE(ns_parse_table);
 
+	acpi_ex_enter_interpreter();
+
 	/*
 	 * AML Parse, pass 1
 	 *
@@ -185,7 +188,7 @@ acpi_ns_parse_table(u32 table_index, str
 	status = acpi_ns_one_complete_parse(ACPI_IMODE_LOAD_PASS1,
 					    table_index, start_node);
 	if (ACPI_FAILURE(status)) {
-		return_ACPI_STATUS(status);
+		goto error_exit;
 	}
 
 	/*
@@ -201,8 +204,10 @@ acpi_ns_parse_table(u32 table_index, str
 	status = acpi_ns_one_complete_parse(ACPI_IMODE_LOAD_PASS2,
 					    table_index, start_node);
 	if (ACPI_FAILURE(status)) {
-		return_ACPI_STATUS(status);
+		goto error_exit;
 	}
 
+error_exit:
+	acpi_ex_exit_interpreter();
 	return_ACPI_STATUS(status);
 }


Patches currently in stable-queue which might be from lv.zheng@intel.com are

queue-4.6/acpica-namespace-fix-deadlock-triggered-by-mlc-support-in-dynamic-table-loading.patch