Messages in this thread | | | Date | Tue, 15 Nov 2022 16:34:10 +0100 | From | Petr Mladek <> | Subject | replay log: Re: [PATCH printk v4 38/39] printk: relieve console_lock of list synchronization duties |
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On Mon 2022-11-14 17:35:31, John Ogness wrote: > The console_list_lock provides synchronization for console list and > console->flags updates. All call sites that were using the console_lock > for this synchronization have either switched to use the > console_list_lock or the SRCU list iterator. > > Remove console_lock usage for console list updates and console->flags > updates. > > Signed-off-by: John Ogness <john.ogness@linutronix.de>
> --- a/kernel/printk/printk.c > +++ b/kernel/printk/printk.c > @@ -3334,6 +3330,11 @@ void register_console(struct console *newcon) > * boot console that is the furthest behind. > */ > if (bootcon_registered && !keep_bootcon) { > + /* > + * Hold the console_lock to guarantee safe access to > + * console->seq. > + */ > + console_lock(); > for_each_console(con) { > if ((con->flags & CON_BOOT) && > (con->flags & CON_ENABLED) && > @@ -3341,6 +3342,7 @@ void register_console(struct console *newcon) > newcon->seq = con->seq; > } > } > + console_unlock();
Thinking more about it. This console_unlock() will actually cause flushing the boot consoles. A solution would be to call console_flush_all() here.
And we could/should solve this in a separate patch. This code was not locked before. It is a corner case. It could be solved later.
> } > } >
Best Regards, Petr
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