From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (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 30A1830DD22 for ; Mon, 12 Jan 2026 07:49:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.92.199 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768204171; cv=none; b=PJQqIkbj1q1SFIZm4ynGDIiX3gKc8d4XsOrgm64JvIKb/joEIS4V+6eOFHWpY8BCAtnj+14yKwNqO3mrQ3aejyncBG1m1n4dXNyMnYuLTdZoI+odxo/1dnZLhxDKGD4aKcu9gETj9u047VMcPgD/rMf7GOVdCA58ndlN9lZ8tMY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768204171; c=relaxed/simple; bh=+pINuJf6bRrdiC7BxEIrfmAViXhmFhWvuuGL+Fsfywc=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Ud3hk3eWhzbJS6852crGOXA8dCBKrqCeAefcq85Lq5iGUdiIqSkBecs6cRlpMjCZjai6sBNPYTyvtIO0A21QWBBcetwOl2212pKNK6216h5hibSEwhYYAG7WSmCV9tKiS2PHnxy31d1h/VpTJeVH5hmdULlV9RyE8ESCOsf/+P8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=PZd1pO9P; arc=none smtp.client-ip=90.155.92.199 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="PZd1pO9P" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=tZECZXlN8ZpKsSpPBuMGAk4sKXm2u3dkMi608pR9X80=; b=PZd1pO9PBx3E+NZcoaarnlzwIE naLVvaU63rQv1DGablHhzi5o9jUtoi99Dy6x2lcvfg/DKr544hXiIQGL9jHjywk+Lp3RtAxiSWaF/ dO+fVIkhERvUOPuou9S9AKRE19kikC2R/khFvROrV5gB8i7fQNm9Tv6ARV1EZ3QHRx4FVNHoeFC3a sHL2rPDB8Fj8bTtBUzYyX7StcOw7NLs0ZlHynu8y2/L+D6KNkMxoAaqeeGmzs6aHKQW3iq4vSUQBq aQJmyei4jnSys6e1Rxn8eYoUdSsrZt2ejgFDvolzdjDkPhtai5oXTEidetMTtt88MkxrGvfzVaGbj TOg4foYA==; Received: from 77-249-17-252.cable.dynamic.v4.ziggo.nl ([77.249.17.252] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.98.2 #2 (Red Hat Linux)) id 1vfCfn-00000000C75-226V; Mon, 12 Jan 2026 07:49:17 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id EC0F6302D3E; Mon, 12 Jan 2026 08:49:10 +0100 (CET) Date: Mon, 12 Jan 2026 08:49:10 +0100 From: Peter Zijlstra To: Pnina Feder Cc: "akpm@linux-foundation.org" , "pmladek@suse.com" , "bhe@redhat.com" , "linux-kernel@vger.kernel.org" , "lkp@intel.com" , "mgorman@suse.de" , "mingo@redhat.com" , "rostedt@goodmis.org" , "senozhatsky@chromium.org" , "tglx@linutronix.de" , Vladimir Kondratiev Subject: Re: [PATCH v4] panic: add panic_force_cpu= parameter to redirect panic to a specific CPU Message-ID: <20260112074910.GC830755@noisy.programming.kicks-ass.net> References: <20260105081808.1771473-1-pnina.feder@mobileye.com> <20260107215659.3619730-1-pnina.feder@mobileye.com> <20260108074857.GD272712@noisy.programming.kicks-ass.net> 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: On Thu, Jan 08, 2026 at 08:09:33PM +0000, Pnina Feder wrote: > > Also, if this is a 'requirement' for kexec or the like, this > > shouldn't be a command line argument, but something that's set-up by > > kexec itself for functional reasons. > > Since the redirection needs to happen before other CPUs are stopped, > would a sysctl be preferable? The user could set it when loading the > crash kernel. I was more thinking about platform setup, it would set this on boot, and equally dis-allow hot-unplug of the magical CPU.