From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 6CFDD7EEFD for ; Wed, 19 Jun 2024 09:28:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718789308; cv=none; b=dLMqxQgO1Q3WaAlhtNAOMNrpJ8TBtmxPWxBSsxO/b7Y1bbqByxVImsSXH0lKi45twOVnNpnXoH7qae90oXkvNAK3G0a7k46A1ADr0D+PRwRTBUaQJuRMGJJ91Z6nPdWytvpqSerhYLwUGUr67/+/m83H6pU81EIrjlStybij8i4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718789308; c=relaxed/simple; bh=WufxOsxR/bUrhyOCBsQoIi+3GMc3jHQidh5GMUPn48I=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=ZymJJ+X87KEKVJEBTv5Yclnk6rCXOsX3/a6+RsL4uvXiVa44UOtp9iIALrB749I/I9PewKOTwoXhShzxi2/jE0LQnOo5Nggw+HQdxBwZKjnlxazk9nx4qfKuIA+nW/32UGbDjzwtsVsyBsPXWRsqM9QCh4JvI4spFrXdak7eGK4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=LXHbokv9; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="LXHbokv9" Received: by smtp.kernel.org (Postfix) with ESMTPSA id AF1C3C4AF1A; Wed, 19 Jun 2024 09:28:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1718789308; bh=WufxOsxR/bUrhyOCBsQoIi+3GMc3jHQidh5GMUPn48I=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=LXHbokv9hHKBEINlK7fBxr437HVEsbXm2xNKwjVwRJrjTzNGePrKqUJsOnGAkorR+ i9Vy8tbcrA+G2Q/N+Zch9qZEX4Q9Jod3fuVgljb4J2F2UY2GsrTQQvlmI8nl1oHOeM xdNDAU/RlQsdTMB2/Goz/GClogUr4KaLsc5WG+48= Date: Wed, 19 Jun 2024 11:28:25 +0200 From: Greg KH To: Thomas Gleixner Cc: oleg@redhat.com, stable@vger.kernel.org Subject: Re: [PATCH 6.6.y and earlier] tick/nohz_full: Don't abuse smp_call_function_single() in tick_setup_device() Message-ID: <2024061917-sheet-galvanize-56e6@gregkh> References: <2024061706-smudgy-gumball-93c0@gregkh> <87ed8vs3y9.ffs@tglx> Precedence: bulk X-Mailing-List: stable@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: <87ed8vs3y9.ffs@tglx> On Mon, Jun 17, 2024 at 10:35:10PM +0200, Thomas Gleixner wrote: > > From: Oleg Nesterov > > commit 07c54cc5988f19c9642fd463c2dbdac7fc52f777 upstream. > > After the recent commit 5097cbcb38e6 ("sched/isolation: Prevent boot crash > when the boot CPU is nohz_full") the kernel no longer crashes, but there is > another problem. > > In this case tick_setup_device() calls tick_take_do_timer_from_boot() to > update tick_do_timer_cpu and this triggers the WARN_ON_ONCE(irqs_disabled) > in smp_call_function_single(). > > Kill tick_take_do_timer_from_boot() and just use WRITE_ONCE(), the new > comment explains why this is safe (thanks Thomas!). > > Fixes: 08ae95f4fd3b ("nohz_full: Allow the boot CPU to be nohz_full") > Signed-off-by: Oleg Nesterov > Signed-off-by: Thomas Gleixner > Cc: stable@vger.kernel.org > Link: https://lore.kernel.org/r/20240528122019.GA28794@redhat.com > Link: https://lore.kernel.org/all/20240522151742.GA10400@redhat.com > --- > Backport to v6.6.y and earlier Now queued up, thanks. greg k-h