From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B8EB8C433EF for ; Sat, 30 Apr 2022 16:00:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1359063AbiD3QDa (ORCPT ); Sat, 30 Apr 2022 12:03:30 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34072 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237621AbiD3QD3 (ORCPT ); Sat, 30 Apr 2022 12:03:29 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BE96C1E0 for ; Sat, 30 Apr 2022 09:00:04 -0700 (PDT) From: John Ogness DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1651334402; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=Qg1MCgJs2GcRC2WuVMspd/xJnQOLWy76IzXScV+vSNk=; b=IqVNzG6jeHs2vRnqXL9KedXJ5Nneq6PU2Es22DQIRToeG6DxaGNtLE3alDyeUYg1NNXbOG tZ5XcIkOHripIzsDCl40gvjVoeCYFnsv3kIVTij3HVhFSbNAgA/OHxPOKwZ7QiSfsMRYY/ AKhmpUiowRf81wz2OqN2Nn8wIhdctPHZNGBoxbkYoAwaA9/I/AluFXejieBz+3KlM4g/Z2 iKRS2FZRwUrkL3wils42n513HmsViL/r2SDCbL7F2dBAwdVytWoLh/B69hWiiNosVfG2Qh qJJWhS3AfrCTqxEasuJKpNEnLt4tU06cLpUriIUxCouOwCQS9hu0CqIV3Q1SGA== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1651334402; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=Qg1MCgJs2GcRC2WuVMspd/xJnQOLWy76IzXScV+vSNk=; b=lMdtoPUqqUTWycR9kLDoc1fYvtjsVvRXJ59N0pmRiF9K6BpLaSHO3eFzBjunfsjoOtlmtm 8nTsnQ0RomQDUrCQ== To: Marek Szyprowski , Petr Mladek Cc: Sergey Senozhatsky , Steven Rostedt , Thomas Gleixner , linux-kernel@vger.kernel.org, Greg Kroah-Hartman , linux-amlogic@lists.infradead.org Subject: Re: [PATCH printk v5 1/1] printk: extend console_lock for per-console locking In-Reply-To: <51dfc4a0-f6cf-092f-109f-a04eeb240655@samsung.com> References: <20220421212250.565456-1-john.ogness@linutronix.de> <20220421212250.565456-15-john.ogness@linutronix.de> <878rrs6ft7.fsf@jogness.linutronix.de> <2a82eae7-a256-f70c-fd82-4e510750906e@samsung.com> <87fslyv6y3.fsf@jogness.linutronix.de> <51dfc4a0-f6cf-092f-109f-a04eeb240655@samsung.com> Date: Sat, 30 Apr 2022 18:06:01 +0206 Message-ID: <87k0b6blz2.fsf@jogness.linutronix.de> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2022-04-29, Marek Szyprowski wrote: > The same issue happens if I boot with init=/bin/bash Very interesting. Since you are seeing all the output up until you try doing something, I guess receiving UART data is triggering the issue. > I found something really interesting. When lockup happens, I'm still > able to log via ssh and trigger any magic sysrq action via > /proc/sysrq-trigger. If you boot the system and directly login via ssh (without sending any data via serial), can you trigger printk output on the UART? For example, with: echo hello > /dev/kmsg (You might need to increase your loglevel to see it.) > It turned out that the UART console is somehow blocked, but it > receives and buffers all the input. For example after issuing "echo > >/proc/sysrq-trigger" from the ssh console, the UART console has been > updated and I see the magic sysrq banner and then all the commands I > blindly typed in the UART console! However this doesn't unblock the > console. sysrq falls back to direct printing. This would imply that the kthread printer is somehow unable to print. > Here is the output of 't' magic sys request: > > https://pastebin.com/fjbRuy4f It looks like the call trace for the printing kthread (pr/ttyAML0) is corrupt. Could you post your kernel config? John