From: Robin Getz <[email protected]>
This is a followup to the cleanups for earlyprintk patch from Gerd Hoffmann
http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=69331af79cf29e26d1231152a172a1a10c2df511
This ensures that a bootconsole is unregistered if it is not replaced.
The current implementation spews garbage out the bootconsole in this case,
since the bootconsole structure is normally in the init section, and is
freed, but still used.
Signed-off-by: Robin Getz <[email protected]>
---
linux-2.6.x/kernel/printk.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)
Index: linux-2.6.x/kernel/printk.c
===================================================================
--- linux-2.6.x/kernel/printk.c
+++ linux-2.6.x/kernel/printk.c
@@ -1104,6 +1104,20 @@
}
EXPORT_SYMBOL(unregister_console);
+static int __init disable_boot_consoles(void)
+{
+ struct console *con;
+
+ for (con = console_drivers; con; con = con->next) {
+ if (con->flags & CON_BOOT) {
+ printk(KERN_INFO "Turn off boot console %s%d\n",
+ con->name, con->index);
+ unregister_console(con);
+ }
+ }
+}
+late_initcall(disable_boot_consoles);
+
/**
* tty_write_message - write a message to a certain tty, not just the console.
* @tty: the destination tty_struct
On 8/19/07, Robin Getz <[email protected]> wrote:
> +static int __init disable_boot_consoles(void)
> +{
> + struct console *con;
> +
> + for (con = console_drivers; con; con = con->next) {
> + if (con->flags & CON_BOOT) {
> + printk(KERN_INFO "Turn off boot console %s%d\n",
> + con->name, con->index);
> + unregister_console(con);
> + }
> + }
> +}
erp, no 'return 0;' ... that'll earn you a warning at build time and
maybe random failures depending on the arch ...
-mike
On Sun, Aug 19, 2007 at 11:11:47PM -0400, Mike Frysinger wrote:
> On 8/19/07, Robin Getz <[email protected]> wrote:
> > +static int __init disable_boot_consoles(void)
> > +{
> > + struct console *con;
> > +
> > + for (con = console_drivers; con; con = con->next) {
> > + if (con->flags & CON_BOOT) {
> > + printk(KERN_INFO "Turn off boot console %s%d\n",
> > + con->name, con->index);
> > + unregister_console(con);
> > + }
> > + }
> > +}
>
> erp, no 'return 0;' ... that'll earn you a warning at build time and
> maybe random failures depending on the arch ...
Or better yet, complain if unregister_console() fails, and pass the
failure down.
From: Robin Getz <[email protected]>
This is a followup to the cleanups for earlyprintk patch from Gerd Hoffmann
http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=69331af79cf29e26d1231152a172a1a10c2df511
This ensures that a bootconsole is unregistered if it is not replaced.
The current implementation spews garbage out the bootconsole in this case,
since the bootconsole structure is normally in the init section, and is
freed, but still used.
Signed-off-by: Robin Getz <[email protected]>
---
linux-2.6.x-old/kernel/printk.c | 15 +++++++++++++++
1 file changed, 15 insertions(+)
Index: linux-2.6.x-old/kernel/printk.c
===================================================================
--- linux-2.6.x-old/kernel/printk.c (revision 3583)
+++ linux-2.6.x-old/kernel/printk.c (working copy)
@@ -1104,6 +1104,21 @@
}
EXPORT_SYMBOL(unregister_console);
+static int __init disable_boot_consoles(void)
+{
+ struct console *con;
+
+ for (con = console_drivers; con; con = con->next) {
+ if (con->flags & CON_BOOT) {
+ printk(KERN_INFO "Turn off boot console %s%d\n",
+ con->name, con->index);
+ unregister_console(con);
+ }
+ }
+ return 0;
+}
+late_initcall(disable_boot_consoles);
+
/**
* tty_write_message - write a message to a certain tty, not just the console.
* @tty: the destination tty_struct
Try #3...
From: Robin Getz <[email protected]>
This is a followup to the cleanups for earlyprintk patch from Gerd Hoffmann
http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=69331af79cf29e26d1231152a172a1a10c2df511
This ensures that a bootconsole is unregistered if it is not replaced.
The current implementation spews garbage out the bootconsole in this case,
since the bootconsole structure is normally in the init section, and is
freed, but still used.
Signed-off-by: Robin Getz <[email protected]>
CC: Gerd Hoffmann <[email protected]>
CC: Paul Mundt <[email protected]>
CC: Mike Frysinger <[email protected]>
---
printk.c | 13 +++++++++++++
1 file changed, 13 insertions(+)
Index: linux-2.6.x/kernel/printk.c
===================================================================
--- linux-2.6.x/kernel/printk.c
+++ linux-2.6.x/kernel/printk.c
@@ -1104,6 +1104,19 @@
}
EXPORT_SYMBOL(unregister_console);
+static int __init disable_boot_consoles(void)
+{
+ printk(KERN_INFO "here\n");
+
+ if (console_drivers->flags & CON_BOOT) {
+ printk(KERN_INFO "turn off boot console %s%d\n",
+ console_drivers->name, console_drivers->index);
+ return unregister_console(console_drivers);
+ }
+ return 0;
+}
+late_initcall(disable_boot_consoles);
+
/**
* tty_write_message - write a message to a certain tty, not just the console.
* @tty: the destination tty_struct
Robin Getz wrote:
> Try #3...
>
> From: Robin Getz <[email protected]>
> +static int __init disable_boot_consoles(void)
> +{
> + printk(KERN_INFO "here\n");
leftover debug printk?
cheers,
Gerd
Try #4... (sorry)
From: Robin Getz <[email protected]>
This is a followup to the cleanups for earlyprintk patch from Gerd Hoffmann
http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=69331af79cf29e26d1231152a172a1a10c2df511
This ensures that a bootconsole is unregistered if it is not replaced.
The current implementation spews garbage out the bootconsole in this case,
since the bootconsole structure is normally in the init section, and is
freed, but still used.
Signed-off-by: Robin Getz <[email protected]>
CC: Gerd Hoffmann <[email protected]>
CC: Paul Mundt <[email protected]>
CC: Mike Frysinger <[email protected]>
---
kernel/printk.c | 11 +++++++++++
1 file changed, 11 insertions(+)
Index: linux-2.6.x/kernel/printk.c
===================================================================
--- linux-2.6.x/kernel/printk.c (revision 3583)
+++ linux-2.6.x/kernel/printk.c (working copy)
@@ -1104,6 +1104,17 @@
}
EXPORT_SYMBOL(unregister_console);
+static int __init disable_boot_consoles(void)
+{
+ if (console_drivers->flags & CON_BOOT) {
+ printk(KERN_INFO "turn off boot console %s%d\n",
+ console_drivers->name, console_drivers->index);
+ return unregister_console(console_drivers);
+ }
+ return 0;
+}
+late_initcall(disable_boot_consoles);
+
/**
* tty_write_message - write a message to a certain tty, not just the console.
* @tty: the destination tty_struct
Robin Getz wrote:
> This ensures that a bootconsole is unregistered if it is not replaced.
> The current implementation spews garbage out the bootconsole in this case,
> since the bootconsole structure is normally in the init section, and is
> freed, but still used.
>
> Signed-off-by: Robin Getz <[email protected]>
> CC: Gerd Hoffmann <[email protected]>
Acked-by: Gerd Hoffmann <[email protected]>
cheers,
Gerd
On Mon, Aug 20, 2007 at 03:22:47PM -0400, Robin Getz wrote:
> Try #4... (sorry)
>
> From: Robin Getz <[email protected]>
>
> This is a followup to the cleanups for earlyprintk patch from Gerd Hoffmann
>
> http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=69331af79cf29e26d1231152a172a1a10c2df511
>
> This ensures that a bootconsole is unregistered if it is not replaced.
> The current implementation spews garbage out the bootconsole in this case,
> since the bootconsole structure is normally in the init section, and is
> freed, but still used.
>
> Signed-off-by: Robin Getz <[email protected]>
> CC: Gerd Hoffmann <[email protected]>
> CC: Paul Mundt <[email protected]>
> CC: Mike Frysinger <[email protected]>
Looks better, thanks.
Acked-by: Paul Mundt <[email protected]>
From: Robin Getz <[email protected]>
Gerd Hoffmann pointed out that my patch from yesterday can lead
to a null pointer dereference if the kernel is booted with no
console, and no earlyprintk defined. This fixes that issue.
printk.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
Signed-off-by: Robin Getz <[email protected]>
---
Index: linux-2.6.x/kernel/printk.c
===================================================================
--- linux-2.6.x/kernel/printk.c
+++ linux-2.6.x/kernel/printk.c
@@ -1106,10 +1106,12 @@
static int __init disable_boot_consoles(void)
{
- if (console_drivers->flags & CON_BOOT) {
- printk(KERN_INFO "turn off boot console %s%d\n",
- console_drivers->name, console_drivers->index);
- return unregister_console(console_drivers);
+ if (console_drivers != NULL) {
+ if (console_drivers->flags & CON_BOOT) {
+ printk(KERN_INFO "turn off boot console %s%d\n",
+ console_drivers->name, console_drivers->index);
+ return unregister_console(console_drivers);
+ }
}
return 0;
}