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 4FF0F36C599; Sun, 8 Mar 2026 16:58:25 +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=1772989106; cv=none; b=fxpHFNd9g+NoZ9meaS/JIPtesGmdFclgG/L5vqbmEgSx/LfkZyW2CiPpb/x41D+831mseuUqThC7qQ7Dhhk9UoZ0AcRjGb3O0xvawKI23NWSeq+HUUbZysY5vllFshZedQOETecVTRGO3BzoSSW2Dh+cDQ7E7eJvW/+NzuWlv1E= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772989106; c=relaxed/simple; bh=csuDDmQUnwguBiq4+JZat8SV2l/GqXHFvrAKc109vHU=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=KXlesJFjb1l8j41DeAjIxVndfnkruByB02AJ7K0sg1/K+FZvHC8VItOVBomzGdDJEfkvHHggT9bQWD9vvJdCK4KIdkViMID+QrPG5RX3J/5ygYUnn42zvTVOTcHeXnwn8iG5IB5yRlfkpyIriQbGaWznTC3FkDIxs6tWmMwK3j0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=cHNthfgw; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="cHNthfgw" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E074EC116C6; Sun, 8 Mar 2026 16:58:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1772989105; bh=csuDDmQUnwguBiq4+JZat8SV2l/GqXHFvrAKc109vHU=; h=From:To:Cc:Subject:In-Reply-To:References:Date:From; b=cHNthfgwDqntovvB18ootlkTTvGH7yhvj+9JaRyixo95eyizCxRr2wtZN7CnGusH+ 5qDTU51vqRLFJLWiMdvzCCcFALfpem18eE+Ia30vCaPIHH9PPtDq2DRE9b+Q/ApPF6 2M10EK3E1+T8nbDWOkIRrSKWv3yerwqRcWfj0FFsYB/P33NJO0V0yf6uXJInh65/5N x15j6N3UM7eJ3BM6F28XedPb8BXsPOkS1ad3sLOFoAMu1ACEqCjGasSTCkvvPMdxZr 6DzmGu+bApgAKHkFHqEZ6F9xAWG8/+8J7iFg7ReoGGw6LX1zuZ3vgY3BCvNosG5DQw Hg3XCvgCcSj+Q== From: Thomas Gleixner To: Peter Zijlstra Cc: Jiri Slaby , Matthieu Baerts , Stefan Hajnoczi , Stefano Garzarella , kvm@vger.kernel.org, virtualization@lists.linux.dev, Netdev , rcu@vger.kernel.org, MPTCP Linux , Linux Kernel , Shinichiro Kawasaki , "Paul E. McKenney" , Dave Hansen , "luto@kernel.org" , Michal =?utf-8?Q?Koutn=C3=BD?= , Waiman Long , Marco Elver Subject: Re: Stalls when starting a VSOCK listening socket: soft lockups, RCU stalls, timeout In-Reply-To: <87eclu3coa.ffs@tglx> References: <863a5291-a636-47d0-891c-bb0524d2e134@kernel.org> <20260302114636.GL606826@noisy.programming.kicks-ass.net> <717310d8-6274-4b7f-8a19-561c45f5f565@kernel.org> <87zf4m2qvo.ffs@tglx> <47cba228-bba7-4e58-a69d-ea41f8de6602@kernel.org> <87tsuu2i59.ffs@tglx> <7efde2b5-3b72-4858-9db0-22493d446301@kernel.org> <87qzpx2sck.ffs@tglx> <20260306152458.GT606826@noisy.programming.kicks-ass.net> <87ldg42eu7.ffs@tglx> <87h5qr2rzi.ffs@tglx> <87eclu3coa.ffs@tglx> Date: Sun, 08 Mar 2026 17:58:22 +0100 Message-ID: <87v7f61cnl.ffs@tglx> Precedence: bulk X-Mailing-List: rcu@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain On Sun, Mar 08 2026 at 10:15, Thomas Gleixner wrote: > On Sat, Mar 07 2026 at 23:29, Thomas Gleixner wrote: >> I'll look at it more tomorrow in the hope that this rested brain >> approach works out again. > > There is another one of the same category. Combo patch below. This rested brain thing is clearly a myth. The patch actually solves nothing because the code ensures that the TRANSIT bit is never set together with the ONCPU bit. One of those moments where you just hope that the earth opens up and swallows you. So I'm back to square one. I go and do what I should have done in the first place. Write a debug patch with trace_printks and let the people who can actually trigger the problem run with it.