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 0EF0E397E9D for ; Mon, 30 Mar 2026 19:50:47 +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=1774900250; cv=none; b=iDw8cQRBmXrI5zDng+QUJ+vutMhSEIwrDKogG4ChHv3Hs2GuuyvJ9wU2PCVwoXNYbdmVRf7VCW/abw744GxJgtIHen46wcFZNiuI090x9ui988LYjbykf8tDY9yt1+I+fMdWPfeIU0PvMSEjcZT+VjNwRP8D34ITncU3J6XOuxg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774900250; c=relaxed/simple; bh=jFGfVupkLD3rMMbDF2TGlhII1EMbLoB9x3abW8GpgHo=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=V7bSnfid465y8mHCzSZT0wqkP6pVE0M5g43hfalu2dwTXKFjVxbLzo8ffO3boUDrnkOGzHiyK1AjcxVJtY8eSl/rdk3ZWvmO6YaycUBrdAr7KSAdagxZeA/3f6cUuI5kmKeoEPt5EizgtQnkCZDTFWOKeYLjgTshCH9JaOFvxME= 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=lrqLj7Op; 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=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="lrqLj7Op" 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=+/JZYP5QpagLtvYaNDs6zLVTNxiHm41ao7r0f9+QWbk=; b=lrqLj7OpiuMThbJqI0C+rxdc3Y /zT/e2U37UGCeJN4BGoYvwNO7fuW9fCCV3uZ/LUYDlUnTCU4gVBJMVBhK0WmVb/SMmJc5NX8gRKQC lxgLIATuxxsvk/wd5WGfYodYcGhjbnz8g/l+AApQfhp2OH651aAY67gAsBpLpZp5pCtW6XHzWe+t0 fe6WnnXuw0I/MrtS5fQtrF/q0cmsNisxm0YDGYMswtqKpN8wKrdn4Opkt3g1TGwW82tFiSHpouL7Z 201ALQBT5ALZqt/BqLS6IklEF/acxA+EHRnDai4pTyaYCuLaDercrVK3E9GXSQ/ZQ80Nwebke1sqA PjwU3t4w==; Received: from 2001-1c00-8d85-4b00-266e-96ff-fe07-7dcc.cable.dynamic.v6.ziggo.nl ([2001:1c00:8d85:4b00:266e:96ff:fe07:7dcc] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.98.2 #2 (Red Hat Linux)) id 1w7IdJ-00000007DfV-28lM; Mon, 30 Mar 2026 19:50:45 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id 465E0301BDE; Mon, 30 Mar 2026 21:50:37 +0200 (CEST) Date: Mon, 30 Mar 2026 21:50:37 +0200 From: Peter Zijlstra To: "Borah, Chaitanya Kumar" Cc: willy@infradead.org, linux-kernel@vger.kernel.org, "intel-gfx@lists.freedesktop.org" , "intel-xe@lists.freedesktop.org" , "Kurmi, Suresh Kumar" , "Saarinen, Jani" , ravitejax.veesam@intel.com Subject: Re: Regression on linux-next (next-20260324 ) Message-ID: <20260330195037.GW2872@noisy.programming.kicks-ass.net> References: <20260327163100.GL3738010@noisy.programming.kicks-ass.net> <20260327164353.GM3739106@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 Mon, Mar 30, 2026 at 01:56:33PM +0530, Borah, Chaitanya Kumar wrote: > > diff --git a/kernel/locking/ww_mutex.h b/kernel/locking/ww_mutex.h > > index b1834ab7e782..bb8b410779d4 100644 > > --- a/kernel/locking/ww_mutex.h > > +++ b/kernel/locking/ww_mutex.h > > @@ -42,7 +42,7 @@ __ww_waiter_last(struct mutex *lock) > > struct mutex_waiter *w = lock->first_waiter; > > if (w) > > - w = list_prev_entry(w, list); > > + w = __ww_waiter_prev(lock, w); > > return w; > > } > Thank you for the response, Peter. Unfortunately, the issue is still seen > with this change. Bah, indeed. Looking at this after the weekend I see that it's actually wrong. But I haven't yet had a new idea. I don't suppose there is a relatively easy way to reproduce this issue outside of your CI robot? My current working thesis is that since this is graphics, this is ww_mutex related. I'll go over this code once more...