printk: flush consoles before checking progress

Commit 9e70a5e109a4 ("printk: Add per-console suspended state")
removed console lock usage during resume and replaced it with
the clearly defined console_list_lock and srcu mechanisms.

However, the console lock usage had an important side-effect
of flushing the consoles. After its removal, consoles were no
longer flushed before checking their progress.

Add the console_lock/console_unlock dance to the beginning
of __pr_flush() to actually flush the consoles before checking
their progress. Also add comments to clarify this additional
usage of the console lock.

Note that console_unlock() does not guarantee flushing all messages
since the commit dbdda842fe96f89 ("printk: Add console owner and waiter
logic to load balance console writes").

Reported-by: Todd Brandt <[email protected]>
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=217955
Fixes: 9e70a5e109a4 ("printk: Add per-console suspended state")
Co-developed-by: Petr Mladek <[email protected]>
Signed-off-by: Petr Mladek <[email protected]>
Signed-off-by: John Ogness <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

0 files changed, 0 insertions, 0 deletions