linux-kernel - [PATCH 2/3] drm/amd/display: Don't invoke kgdb

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Date:   Fri, 23 Oct 2020 09:46:55 +0200
From:   Takashi Iwai <tiwai@...e.de>
To:     dri-devel@...ts.freedesktop.org
Cc:     amd-gfx@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Subject: [PATCH 2/3] drm/amd/display: Don't invoke kgdb_breakpoint() unconditionally

ASSERT_CRITICAL() invokes kgdb_breakpoint() whenever either
CONFIG_KGDB or CONFIG_HAVE_KGDB is set.  This, however, may lead to a
kernel panic when no kdb stuff is attached, since the
kgdb_breakpoint() call issues INT3.  It's nothing but a surprise for
normal end-users.

For avoiding the pitfall, make the kgdb_breakpoint() call only when
CONFIG_DEBUG_KERNEL_DC is set.

https://bugzilla.opensuse.org/show_bug.cgi?id=1177973
Cc: <stable@...r.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@...e.de>
---
 drivers/gpu/drm/amd/display/dc/os_types.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/display/dc/os_types.h b/drivers/gpu/drm/amd/display/dc/os_types.h
index 330acaaed79a..32758b245754 100644
--- a/drivers/gpu/drm/amd/display/dc/os_types.h
+++ b/drivers/gpu/drm/amd/display/dc/os_types.h
@@ -94,7 +94,7 @@
  * general debug capabilities
  *
  */
-#if defined(CONFIG_HAVE_KGDB) || defined(CONFIG_KGDB)
+#if defined(CONFIG_DEBUG_KERNEL_DC) && (defined(CONFIG_HAVE_KGDB) || defined(CONFIG_KGDB))
 #define ASSERT_CRITICAL(expr) do {	\
 	if (WARN_ON(!(expr))) { \
 		kgdb_breakpoint(); \
-- 
2.16.4