From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) (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 220F22DC767; Thu, 11 Jun 2026 11:08:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.50.34 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781176109; cv=none; b=P9PxeUKdvT4sxpRl+L9/Ij/AWue5Ycdo+NztkP3DhhcPkwpPKgfgG0DwElzysijO5yfKJoKtS0Vkq42hCiLcMB9SEk51cUr7Gdc9dEAnDu/2p3zv99XrfZS3nvjg1uySHtwOnHgha/9H9JlwXfheOBtR3KCpScbf9x/XCBR5Usw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781176109; c=relaxed/simple; bh=wQ3WHe+W2v0d92Kplq8+Hn6T8icPXVzVqEyoe1yv1fY=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=MIvlWHCpxY4dYSAnJESb3g7+yytB6JZDk4KCfsK1XvvegFP9TUfjlmcN645QK1ZIQfyhiS9ahhzvu7xHxrN4iqqVy1xvovOeTswi3OXjsEYdLK65sHimaGXeI0l4rPgdjKfboPmtO08PEeuqxGhBun6UA5N1zenGfzskp+o9aTU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org; spf=pass smtp.mailfrom=infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=rmSxXHVh; arc=none smtp.client-ip=90.155.50.34 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=pass 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="rmSxXHVh" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; 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=Be5rEciqOgJ7a/QFo0//CIZoBQIfhUkSPXRNBFzrHCc=; b=rmSxXHVhxwjZG6eIJJik0ch6ti 5Hi6iyJuoT91JesXShCkA+1JQpjZV8FqbTODL8bD798uiBrUiHP6+OvPjUFtbrwhkDSt1xe6TMkX/ +ZZNJxZaCvZiltASsZUnftEE3I7VEPE07tGQslh/9ZmHlsrc3JY33YNPavi5tUMZZH068JdtX/pNq hb0Z97N+MR5hvFTHdhsesPCu1s9Q6G9wDbTjACHPsKUHThqUDTX83U6agSE/Abs23vanIRg9G+GZQ XAFtWRJJ65zV6H7jasCZrC+WVPZUCBuF7xlRzDvYmvRRPZzGk2gCy2o9oOfjx880JgdyTfi0mskBV 4W+jIVJQ==; Received: from 77-249-17-252.cable.dynamic.v4.ziggo.nl ([77.249.17.252] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.99.1 #2 (Red Hat Linux)) id 1wXdGc-00000001mBP-2jhl; Thu, 11 Jun 2026 11:08:11 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id C2490301A42; Thu, 11 Jun 2026 13:08:09 +0200 (CEST) Date: Thu, 11 Jun 2026 13:08:09 +0200 From: Peter Zijlstra To: Sven Schnelle Cc: Alexander Gordeev , Ingo Molnar , Juri Lelli , Vincent Guittot , K Prateek Nayak , Mark Brown , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Valentin Schneider , John Stultz , Vineeth Pillai , Joel Fernandes , Heiko Carstens , Vasily Gorbik , linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, linux-next@vger.kernel.org, Aaron Lu Subject: Re: linux-next crashes in scheduler on s390 Message-ID: <20260611110809.GF187714@noisy.programming.kicks-ass.net> References: <17e75ff4-cf90-4772-9965-92a7235ca806-agordeev@linux.ibm.com> Precedence: bulk X-Mailing-List: linux-s390@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 Wed, Jun 10, 2026 at 03:03:26PM +0200, Sven Schnelle wrote: > Alexander Gordeev writes: > > > Hi All, > > > > Since about June 1st we're getting strace test suite (make -j$(nproc) check) > > crashes on s390 in linux-next. Those are pretty easy to reproduce, but I > > have not been able to nail it down to the particular commit/merge. > > > > I am going to bisect it, but since we are approaching v7.1 release, any > > hint would be greatly appreciated! > > [..] > > I bisected it to > https://lore.kernel.org/all/20260511120627.944705718@infradead.org/ > ("[PATCH v2 08/10] sched/fair: Add newidle balance to pick_task_fair()") > > Adding the patch proposed in > https://lore.kernel.org/all/20260603095108.GA1684319@bytedance.com/ > fixes the issue for me. > > To reproduce, running the strace test suite seems enough. If required, I > can try to figure out the exact test that crashes the kernel. Oh sorry for the borkage and thanks for the pointer -- I clearly missed that :-(. I've just been staring at all this and while I think I prefer a slightly different solution, I think I'm going to just apply that patch since its fairly trivial and you've confirmed it works. And then I can go do the alternative for the next cycle -- and hopefully not wreck it again :-).