On Fri 2018-06-01 14:26:42, Maninder Singh wrote: > This patch make sure printing of log on console if loglevel > at time of storing log is less than current console loglevel. > > @why > In SMP printk can work asynchronously, logs can be missed on console > because it checks current log level at time of console_unlock, > not at time of storing logs. > > func() > { > .... > .... > console_verbose(); // user wants to have all the logs on console. > pr_alert(); > dump_backtrace(); //prints with default loglevel. > ... > console_silent(); // stop all logs from printing on console. > } > > Now if console_lock was owned by another process, the messages might > be handled after the consoles were silenced.
It might make sense to document the limitations reported by Sergey. I mean to add something like: "There are still some corner cases where this patch is not enough, for example, when the messages are flushed later from printk_safe buffers or when there are races between console_verbose() and console_silent() callers." > reused flag LOG_NOCONS as its usage is gone long back. > (5c2992ee7fd8a29d04125dc0aa3522784c5fa5eb) > > Signed-off-by: Vaneet Narang <v.nar...@samsung.com> > Signed-off-by: Maninder Singh <maninder...@samsung.com> Anyway. the patch helps in many situations and it is a step in the right direction: Reviewed-by: Petr Mladek <pmla...@suse.com> Best Regards, Petr PS: There is no need to resend the patch. I could update the commit message when pushing the patch. I am just going to wait a bit for other potential reviewers.