From: Steven Rostedt <rostedt@goodmis.org>
To: LKML <linux-kernel@vger.kernel.org>
Cc: Petr Mladek <pmladek@suse.com>,
Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
Hans de Goede <hdegoede@redhat.com>,
Daniel Vetter <daniel@ffwll.ch>,
Thomas Zimmermann <tzimmermann@suse.de>,
Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>,
Andrew Morton <akpm@linux-foundation.org>,
Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>,
dri-devel <dri-devel@lists.freedesktop.org>,
Linux Fbdev development list <linux-fbdev@vger.kernel.org>
Subject: [PATCH v2] console: Replace #if 1 with a bool to ignore
Date: Thu, 12 Jul 2018 09:29:38 -0400 [thread overview]
Message-ID: <20180712092938.22e33641@gandalf.local.home> (raw)
From: Steven Rostedt (VMware) <rostedt@goodmis.org>
There's been discussion on the fb list about the addition of
WARN_CONSOLE_UNLOCKED() inside the fb code. The complaint is that when
the fb module is loaded with lockless_register_fb the console lock is
not taken for debugging reasons. With the addition of
WARN_CONSOLE_UNLOCK() within the fb code, this causes the console to
fill up with warnings when trying to debug the fb driver.
There's also a #if 1 that enables the warning which was added before
git history, and we look down on constant #if's in the kernel nowadays
anyway.
Remove the #if 1 and add a ignore_console_lock_warning boolean that can
be set by drivers to ignore the warning in order to do debugging.
Link: http://lkml.kernel.org/r/717e6337-e7a6-7a92-1c1b-8929a25696b5@suse.de
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
Changes since V1:
- Added comment to describe ignore_console_unlock_waring variable
- Abide by 80 character limit
Index: linux-trace.git/include/linux/console.h
===================================================================
--- linux-trace.git.orig/include/linux/console.h
+++ linux-trace.git/include/linux/console.h
@@ -200,11 +200,14 @@ void vcs_make_sysfs(int index);
void vcs_remove_sysfs(int index);
/* Some debug stub to catch some of the obvious races in the VT code */
-#if 1
-#define WARN_CONSOLE_UNLOCKED() WARN_ON(!is_console_locked() && !oops_in_progress)
-#else
-#define WARN_CONSOLE_UNLOCKED()
-#endif
+#define WARN_CONSOLE_UNLOCKED() \
+ WARN_ON(!ignore_console_lock_warning && \
+ !is_console_locked() && !oops_in_progress)
+/*
+ * Set ignore_console_lock_warning to true if you need to quiet
+ * WARN_CONSOLE_UNLOCKED() for debugging purposes.
+ */
+extern bool ignore_console_lock_warning;
/* VESA Blanking Levels */
#define VESA_NO_BLANKING 0
Index: linux-trace.git/kernel/printk/printk.c
===================================================================
--- linux-trace.git.orig/kernel/printk/printk.c
+++ linux-trace.git/kernel/printk/printk.c
@@ -66,6 +66,9 @@ int console_printk[4] = {
CONSOLE_LOGLEVEL_DEFAULT, /* default_console_loglevel */
};
+bool ignore_console_lock_warning __read_mostly;
+EXPORT_SYMBOL(ignore_console_lock_warning);
+
/*
* Low level drivers may need that to know if they can schedule in
* their unblank() callback or not. So let's export it.
next reply other threads:[~2018-07-12 13:29 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CGME20180712132944epcas4p3091e1c7a7aa1bd4da95750908012e616@epcas4p3.samsung.com>
2018-07-12 13:29 ` Steven Rostedt [this message]
2018-07-12 13:30 ` [PATCH v2] console: Replace #if 1 with a bool to ignore Steven Rostedt
2018-07-12 13:43 ` Petr Mladek
2018-07-18 8:15 ` Thomas Zimmermann
2018-07-24 16:13 ` Bartlomiej Zolnierkiewicz
2018-07-24 16:18 ` Bartlomiej Zolnierkiewicz
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