linux-kernel - [PATCH] kernel: add boot param to disable stack dump on panic

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Message-ID: <20240206213902.GA1490631@lichtman.org>
Date: Tue, 6 Feb 2024 21:39:02 +0000
From: Nir Lichtman <nir@...htman.org>
To: linux-kernel@...r.kernel.org
Subject: [PATCH] kernel: add boot param to disable stack dump on panic

From: Nir Lichtman <nir@...htman.org>
Date: Sat, 3 Feb 2024 10:19:30 +0200
Subject: [PATCH] kernel: add boot param to disable stack dump on panic

---
 Documentation/admin-guide/kernel-parameters.txt |  5 +++++
 kernel/panic.c                                  | 12 +++++++++++-
 2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 31b3a2568..433e3e5d1 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -1127,6 +1127,11 @@
 			MTRR settings.  This parameter disables that behavior,
 			possibly causing your machine to run very slowly.
 
+	disable_stack_dump_on_panic
+			This parameter disables call stack dumping when there
+			is a panic, which can help obscure less earlier messages
+			that lead to the panic.
+
 	disable_timer_pin_1 [X86]
 			Disable PIN 1 of APIC timer
 			Can be useful to work around chipset bugs.
diff --git a/kernel/panic.c b/kernel/panic.c
index 2807639aa..a1e1d064e 100644
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -266,6 +266,16 @@ static void panic_other_cpus_shutdown(bool crash_kexec)
 		crash_smp_send_stop();
 }
 
+static int disable_stack_dump_on_panic __initdata;
+
+static int __init disable_stack_dump_on_panic_setup(char *str)
+{
+	disable_stack_dump_on_panic = 1;
+	return 0;
+}
+
+early_param("disable_stack_dump_on_panic", disable_stack_dump_on_panic_setup);
+
 /**
  *	panic - halt the system
  *	@fmt: The text string to print
@@ -340,7 +350,7 @@ void panic(const char *fmt, ...)
 	/*
 	 * Avoid nested stack-dumping if a panic occurs during oops processing
 	 */
-	if (!test_taint(TAINT_DIE) && oops_in_progress <= 1)
+	if (!test_taint(TAINT_DIE) && oops_in_progress <= 1 && !disable_stack_dump_on_panic)
 		dump_stack();
 #endif
 
-- 
2.39.2