The patch titled
don't prefer unsuited consoles on registration
has been added to the -mm tree. Its filename is
dont-prefer-unsuited-consoles-on-registration.patch
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------------------------------------------------------
Subject: don't prefer unsuited consoles on registration
From: Jan Kiszka <jan.kiszka@xxxxxx>
KGDB triggers a (probably so far theoretical) issue of the automatic init
console election: If some console happens to be registered first which does
not provide a tty binding (!console->device), it prevents that more suited
consoles which are registered later on can enter the candidate pool for
console_device(). This is observable with KGDB's console which may already
be registered (and exploited!) during early debugger connections, that is
before any regular console registration.
This patch fixes the issue by postponing the final, automated
preferred_console selection until someone with a non-NULL device handler
comes around.
Signed-off-by: Jan Kiszka <jan.kiszka@xxxxxx>
Cc: Jason Wessel <jason.wessel@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: Gerd Hoffmann <kraxel@xxxxxxx>
Cc: Michael Ellerman <michael@xxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/printk.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff -puN kernel/printk.c~dont-prefer-unsuited-consoles-on-registration kernel/printk.c
--- a/kernel/printk.c~dont-prefer-unsuited-consoles-on-registration
+++ a/kernel/printk.c
@@ -1119,8 +1119,11 @@ void register_console(struct console *co
console->index = 0;
if (console->setup == NULL ||
console->setup(console, NULL) == 0) {
- console->flags |= CON_ENABLED | CON_CONSDEV;
- preferred_console = 0;
+ console->flags |= CON_ENABLED;
+ if (console->device) {
+ console->flags |= CON_CONSDEV;
+ preferred_console = 0;
+ }
}
}
_
Patches currently in -mm which might be from jan.kiszka@xxxxxx are
git-x86.patch
dont-prefer-unsuited-consoles-on-registration.patch
-
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