diff options
| author | John Ogness <john.ogness@linutronix.de> | 2023-10-06 10:21:50 +0200 |
|---|---|---|
| committer | Petr Mladek <pmladek@suse.com> | 2023-10-09 10:15:04 +0200 |
| commit | 054c22bd784d6953ac85f545bed4a2a27b0e4ddb (patch) | |
| tree | dcf80e1082fa0ec75f52a245ae0609a89ca1d033 /kernel/printk | |
| parent | 132a90d1527fedba2d95085c951ccf00dbbebe41 (diff) | |
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 <todd.e.brandt@intel.com>
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=217955
Fixes: 9e70a5e109a4 ("printk: Add per-console suspended state")
Co-developed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Link: https://lore.kernel.org/r/20231006082151.6969-2-pmladek@suse.com
Diffstat (limited to 'kernel/printk')
| -rw-r--r-- | kernel/printk/printk.c | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index 8787d3a72114..1919899b6897 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -3738,12 +3738,18 @@ static bool __pr_flush(struct console *con, int timeout_ms, bool reset_on_progre seq = prb_next_seq(prb); + /* Flush the consoles so that records up to @seq are printed. */ + console_lock(); + console_unlock(); + for (;;) { diff = 0; /* * Hold the console_lock to guarantee safe access to - * console->seq. + * console->seq. Releasing console_lock flushes more + * records in case @seq is still not printed on all + * usable consoles. */ console_lock(); |