From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from pandora.armlinux.org.uk (pandora.armlinux.org.uk [78.32.30.218]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 671EC250C15 for ; Tue, 11 Feb 2025 15:05:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=78.32.30.218 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739286349; cv=none; b=KD3qvwOlyJKGUsfchu8BvKLrQqR401oXI/xr7K3f5uHCJ4QjtZ4ynY2kUHdOyuMu7zsrn+3Cc7Aq46U4f4xzIi9sdWYzz73tFbewp5MWNX3C1MqE3agGla4oQrQlTuEeULD95ckpcguZpgkC/GGhp49ByPPWguMPGUGAUqTStQ4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739286349; c=relaxed/simple; bh=gILxc1vlFfC7Cd9Gfzulte7qbvFGDw5/GEDFFZYIvxc=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=NAUkBZhY+qxswmekQjO8GEUjfD3Ih9VxmtLDrzFwAYo7p/BA5wTDmg61r2dlzzJVQokX7FrsWHPbcpWH3wxGEaN0caUIZbGUipJ14x92va9DFX2nO10t9DzDw6mLdehGDHU6lyHCTNjMIFngdblUh8v3VlDecghd1Qg/TnlCZy0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=armlinux.org.uk; spf=none smtp.mailfrom=armlinux.org.uk; dkim=pass (2048-bit key) header.d=armlinux.org.uk header.i=@armlinux.org.uk header.b=da6tO3St; arc=none smtp.client-ip=78.32.30.218 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=armlinux.org.uk Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=armlinux.org.uk Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=armlinux.org.uk header.i=@armlinux.org.uk header.b="da6tO3St" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=armlinux.org.uk; s=pandora-2019; h=Sender:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=wMch1HIVZL0GsRqZJwBamjdSUtwIeuUTfLpGso7d8Mc=; b=da6tO3St4QZjVO9rW5F4uw5AHD FKKdPane4YRfDJt9BuaW78I6ABcPLDGY9pB2W9mebXiwCvIrkcJ6MYsl0ck6XjJrA7Hvq3F8D8/Gk 2p6aS/oHO5W3vxSwSZO8d52Tceo0y+QVrfstynyfMd3Fer0pexVHmRnB/JeC1cKR5u8CaPaxt6tmG RMGSjhW7oY6BSTKK/Etjg1oitWjybsNRHf7qNvvhZqiz10sGQM/PSsA7T3LFQInUbUHUgQGxG7xh/ FPxwbYS7OUqo53l7IkdQne4GIwwQSli6lFvWL+cK1InoT2pakLgxpGldWVToqhIde+fAAtJSZqURN KvoCpPWg==; Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:51408) by pandora.armlinux.org.uk with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1thrpV-0002fz-25; Tue, 11 Feb 2025 15:05:41 +0000 Received: from linux by shell.armlinux.org.uk with local (Exim 4.96) (envelope-from ) id 1thrpS-0000AA-0g; Tue, 11 Feb 2025 15:05:38 +0000 Date: Tue, 11 Feb 2025 15:05:38 +0000 From: "Russell King (Oracle)" To: Sebastian Andrzej Siewior Cc: linux-kernel@vger.kernel.org, linux-rt-devel@lists.linux.dev, Ben Segall , Catalin Marinas , Dietmar Eggemann , Ingo Molnar , Juri Lelli , Mel Gorman , Peter Zijlstra , Shrikanth Hegde , Steven Rostedt , Thomas Gleixner , Valentin Schneider , Vincent Guittot , Will Deacon , linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH v2 3/9] arm: Rely on generic printing of preemption model. Message-ID: References: <20250203141632.440554-1-bigeasy@linutronix.de> <20250203141632.440554-4-bigeasy@linutronix.de> <20250210120429.iFfBClW1@linutronix.de> <20250210153902.06VTSS6d@linutronix.de> <20250211145249.StI6tEZv@linutronix.de> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250211145249.StI6tEZv@linutronix.de> Sender: Russell King (Oracle) On Tue, Feb 11, 2025 at 03:52:49PM +0100, Sebastian Andrzej Siewior wrote: > On 2025-02-10 16:26:56 [+0000], Russell King (Oracle) wrote: > > > This this applied, die("test") on ARM ends as: > > > > > > [ 1.595106] Kernel panic - not syncing: test > > > [ 1.596044] CPU: 3 UID: 0 PID: 1 Comm: swapper/0 Tainted: G W 6.14.0-rc2-00009-gb80a798df08c-dirty #13 PREEMPT > > > [ 1.596768] Tainted: [W]=WARN > > > [ 1.596946] Hardware name: QEMU QEMU Virtual Machine, BIOS unknown 02/02/2022 > > > > Hmm. I've no idea what you're testing, what you've quoted makes zero > > sense to me. > > > > First... > > > > void die(const char *str, struct pt_regs *regs, int err) > > > > is the die function prototype, so it takes a bit more than what you've > > indicated. > > > > Second, "Kernel panic" suggests that panic() has been called. However, > > this only happens when die() is called (or more specifically > > oops_end()) from either interrupt context (in which case we get > > "Kernel panic - Fatal exception in interrupt") or if panic_on_oops > > is set ("Kernel panic - Fatal exception"). > > > > I don't see a path which would result in > > "Kernel panic - not syncing: test" to be printed from this path. > > > > Since __die() does not call dump_stack(), we're not going to call > > dump_stack_print_info() from __die(), so I don't think it's appropriate > > to remove this information. > > Okay. Let me try again with a stack overflow during boot. With the > series: > > | Freeing unused kernel image (initmem) memory: 2048K > | 8<--- cut here --- > | Unable to handle kernel paging request at virtual address df82a000 when write > | [df82a000] *pgd=80000040007003, *pmd=41487003, *pte=00000000 > | Internal error: Oops: a07 [#1] SMP ARM > | Modules linked in: > | CPU: 0 UID: 0 PID: 1 Comm: swapper/0 Tainted: G W 6.14.0-rc2-00009-gdca8d546a8a3-dirty #16 PREEMPT Got it. Printed from __die() -> __show_regs() -> show_regs_print_info() -> dump_stack_print_info(). Reviewed-by: Russell King (Oracle) Thanks! -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last!