linux-kernel - [PATCH] ACPI: OSL: Panic when encountering a fatal ACPI error

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Message-Id: <20260124021859.8337-1-W_Armin@gmx.de>
Date: Sat, 24 Jan 2026 03:18:59 +0100
From: Armin Wolf <W_Armin@....de>
To: rafael@...nel.org,
	lenb@...nel.org
Cc: linux-acpi@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH] ACPI: OSL: Panic when encountering a fatal ACPI error

The ACPI spec states that the operating system should respond
to a fatal ACPI error by "performing a controlled OS shutdown in
a timely fashion". Windows complies with this requirement by entering
a BSOD upon executing the "Fatal()" ASL opcode, a implementation
detail that is used by some firmware implementations for signaling
fatal hardware errors.

Comply with the ACPI specification by triggering a kernel panic
when ACPICA signals a fatal ACPI error. Users can still disable
this behavior by using the acpi.panic_on_fatal kernel option to
work around firmware bugs.

Link: https://uefi.org/specs/ACPI/6.6/19_ASL_Reference.html#fatal-fatal-error-check
Signed-off-by: Armin Wolf <W_Armin@....de>
---
 .../admin-guide/kernel-parameters.txt          |  9 +++++++++
 drivers/acpi/Kconfig                           | 11 +++++++++++
 drivers/acpi/osl.c                             | 18 +++++++++++++++++-
 3 files changed, 37 insertions(+), 1 deletion(-)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 1058f2a6d6a8..140bb239857f 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -187,6 +187,15 @@ Kernel parameters
 			unusable.  The "log_buf_len" parameter may be useful
 			if you need to capture more output.
 
+	acpi.panic_on_fatal=	[ACPI]
+			{0 | 1}
+			Causes the kernel to panic when the ACPI bytecode signals
+			a fatal error. The default value of this setting can
+			be configured using CONFIG_ACPI_PANIC_ON_FATAL.
+			Overriding this value should only be done for diagnosing
+			ACPI firmware problems, as some firmware implementations
+			use this mechanism to signal fatal hardware errors.
+
 	acpi_enforce_resources=	[ACPI]
 			{ strict | lax | no }
 			Check for resource conflicts between native drivers
diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
index df0ff0764d0d..7139e7d8ac25 100644
--- a/drivers/acpi/Kconfig
+++ b/drivers/acpi/Kconfig
@@ -65,6 +65,17 @@ config ACPI_THERMAL_LIB
        depends on THERMAL
        bool
 
+config ACPI_PANIC_ON_FATAL
+	bool "Panic on fatal ACPI error"
+	default y
+	help
+	  The ACPI bytecode can signal that a fatal error has occurred using the Fatal()
+	  ASL operator, normaly causing a kernel panic. Disabling this option causes such
+	  a condition to be treated like a ordinary ACPI error.
+
+	  This setting can also be overridden during boot using the acpi.panic_on_fatal
+	  kernel parameter.
+
 config ACPI_DEBUGGER
 	bool "AML debugger interface"
 	select ACPI_DEBUG
diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c
index 05393a7315fe..b62ea126ea59 100644
--- a/drivers/acpi/osl.c
+++ b/drivers/acpi/osl.c
@@ -12,6 +12,7 @@
 #define pr_fmt(fmt) "ACPI: OSL: " fmt
 
 #include <linux/module.h>
+#include <linux/panic.h>
 #include <linux/kernel.h>
 #include <linux/slab.h>
 #include <linux/mm.h>
@@ -70,6 +71,10 @@ static bool acpi_os_initialized;
 unsigned int acpi_sci_irq = INVALID_ACPI_IRQ;
 bool acpi_permanent_mmap = false;
 
+static bool panic_on_fatal = CONFIG_ACPI_PANIC_ON_FATAL;
+module_param(panic_on_fatal, bool, 0);
+MODULE_PARM_DESC(panic_on_fatal, "Trigger a kernel panic when encountering a fatal ACPI error");
+
 /*
  * This list of permanent mappings is for memory that may be accessed from
  * interrupt context, where we can't do the ioremap().
@@ -1381,9 +1386,20 @@ acpi_status acpi_os_notify_command_complete(void)
 
 acpi_status acpi_os_signal(u32 function, void *info)
 {
+	struct acpi_signal_fatal_info *fatal_info;
+
 	switch (function) {
 	case ACPI_SIGNAL_FATAL:
-		pr_err("Fatal opcode executed\n");
+		fatal_info = info;
+		if (panic_on_fatal) {
+			panic("Fatal ACPI BIOS error (type 0x%X code 0x%X argument 0x%X)",
+			      fatal_info->type, fatal_info->code, fatal_info->argument);
+		} else {
+			pr_emerg("Fatal ACPI BIOS error (type 0x%X code 0x%X argument 0x%X)\n",
+				 fatal_info->type, fatal_info->code, fatal_info->argument);
+			add_taint(TAINT_FIRMWARE_WORKAROUND, LOCKDEP_STILL_OK);
+		}
+
 		break;
 	case ACPI_SIGNAL_BREAKPOINT:
 		/*
-- 
2.39.5