Commit-ID: f97960fbddd98e1b7bfba469b8510b49a62b4bc5
Gitweb: http://git.kernel.org/tip/f97960fbddd98e1b7bfba469b8510b49a62b4bc5
Author: Thomas Gleixner <[email protected]>
AuthorDate: Thu, 17 Nov 2016 17:31:55 +0100
Committer: Thomas Gleixner <[email protected]>
CommitDate: Thu, 17 Nov 2016 19:44:58 +0100
kernel/printk: Block cpuhotplug callback when tasks are frozen
The recent conversion of the console hotplug notifier to the state machine
missed the fact, that the notifier only operated on the non frozen
transitions. As a consequence the console_lock/unlock() pair is also
invoked during suspend, which results in a lockdep warning.
Restore the previous state by making the lock/unlock conditional on
!tasks_frozen.
Fixes: 90b14889d2f9 ("kernel/printk: Convert to hotplug state machine")
Reported-and-tested-by: Borislav Petkov <[email protected]>
Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1611171729320.3645@nanos
Signed-off-by: Thomas Gleixner <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Sebastian Andrzej Siewior <[email protected]>
---
kernel/printk/printk.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index 4487ffc..37893da 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -2194,8 +2194,10 @@ void resume_console(void)
*/
static int console_cpu_notify(unsigned int cpu)
{
- console_lock();
- console_unlock();
+ if (!cpuhp_tasks_frozen) {
+ console_lock();
+ console_unlock();
+ }
return 0;
}
