Messages in this thread | | | Subject | Re: [PATCH] printk: Add loglevel for "do not print to consoles". | From | Dmitry Safonov <> | Date | Fri, 24 Apr 2020 16:52:31 +0100 |
| |
On 4/24/20 4:42 PM, Steven Rostedt wrote: > On Sat, 25 Apr 2020 00:28:53 +0900 > Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp> wrote: >> For those who analyze log files (instead of console output), the point of >> printk() is to save kernel messages into log files (via userspace syslog >> daemon). >> >> By the way, I think >> >> printk(KERN_NO_CONSOLES "hello\n") >> >> is almost same with doing >> >> saved_loglevel = console_loglevel; >> console_loglevel = CONSOLE_LOGLEVEL_SILENT; >> printk("hello\n"); >> console_loglevel = saved_loglevel; >> >> used by vkdb_printf(). > > And both shouldn't be done within the kernel. The "CONSOLE_LOGLEVEL_SILENT" > if for user decided policy, not the kernel making that policy for the user.
Though, I believe the reverse KERN_UNSUPPRESSED [1] still makes sense for sysrq/kdb where user expects their interactive messages to appear on console. And unfortunately, userspace depends on the loglevel of those messages as it is. With KERN_UNSUPPRESSED I hope to remove all those console_loglevel tricks and make it static variable for printk.
[1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima@arista.com/
Thanks, Dmitry
| |