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Subject: RE: [BUG] Threaded printk breaks early debugging Thread-Topic: [BUG] Threaded printk breaks early debugging Thread-Index: AQHYfw5tEBAMEt7XXEKQmWQ8WlSw2q1Nf9Zw Date: Mon, 13 Jun 2022 16:11:19 +0000 Message-ID: References: <87y1y48spg.fsf@jogness.linutronix.de> <8735g9mqo0.fsf@jogness.linutronix.de> <87wndlge43.fsf@jogness.linutronix.de> In-Reply-To: Accept-Language: en-GB, en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.202.205.107] MIME-Version: 1.0 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=C51A453 smtp.mailfrom=david.laight@aculab.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: aculab.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00,RCVD_IN_DNSWL_NONE, SPF_HELO_NONE,SPF_PASS,T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Petr Mladek > Sent: 13 June 2022 11:14 ... > Another interesting alternative is the Peter Zijlstra's mode > where all messages are printed to the console "immediately". > They are serialized only by the CPU-reentrant lock. > > This mode is not good for production system. But it might > be good for debugging. The good thing is that the behavior > is well defined. ISTM that all messages should be output (even if this means that cpu spin waiting for a serial console) until userspace has a chance to set an option to change the behaviour. Oh, and can someone stop the distros hiding the console output. I want to see the 'oops' traceback when I break the kernel! David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)