From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 4DE4D3382C3 for ; Thu, 9 Jul 2026 06:53:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783579991; cv=none; b=PDufp6gmgUN33t4k+/O3IWEP1VvhM988bRXlWFcDVY1zQWiuLonY70S+bo13lNndK4hcq4THkWATIHfJQ0E2OvTxHMlXTKZQ4koqIIDdqU0lZ8j1Q8c6hlFBzR7XHSfrdGp6YV+HKFhKWArsTyas0Soeqby/WosbJkbfVUkBlXA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783579991; c=relaxed/simple; bh=e0PUo8fkABkwfo3rdO1IluywSZEkFXkYFS9PC+NfW60=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=gAaL3q4yWj7l0cm5o2FG4OmxbF2CzoMyX7mwblWG9mNcAZBzL7dzRWVQuePKS7eU3Bz6DZRQpF3A36QXiY527b5o+EmUGDh6k0oKAjPWyqYelmf+LZTN1huAjS0EN4T9vI6KbIqTZMzuKlT9mL+ifBFYTVQFVyUqFNn/1W67yws= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Hniihd0w; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Hniihd0w" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 92FFD1F000E9; Thu, 9 Jul 2026 06:53:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1783579990; bh=z05ytVQA+TaywaNzi9kCD/IAW6ociprds8p1fLLuodo=; h=From:To:Cc:Subject:In-Reply-To:References:Date; b=Hniihd0wBG99LMCQX/gInOOysYvPMVmZWJ3p1BhAsVwBp9XqfHNdGYB9b3eS52jrD sa5MQnGMH1aHSzVlVrc435qEqMXenRpFQIJBAwZVOO/ugfexMyqU4iZanrYHa/wice fK7no07D9Dk+baJo0kgJ2yLh8SJcHtjVhT/eaOUuNpfvIPL7pTbfLCStTeHn1G0SIM +JUwe70QCJ6a//gzvT+wgtaeuO7BioHSdeb/8euW694/9vZsZSoo4mMEi9IM+K/ND3 V/Z+NMdT++HMVrGdpidcYc6UH+HGz8yUbgLbYpDIXWRPR+Atk5C4KUFzWJ6g/vMtYe DgGgEqexrRDqA== From: Thomas Gleixner To: Wu Frank , Sasha Levin Cc: stable@vger.kernel.org, Keenan Dong , Yuan Tan , Juefei Pu , Xin Liu , Sid Kumar Subject: Re: [PATCH 5.15.y] rtmutex: Use waiter::task instead of current in remove_waiter() In-Reply-To: References: <20260708150527.3212183-1-sidkumar1@gmail.com> <20260708194323.agent5-0004@kernel.org> Date: Thu, 09 Jul 2026 08:53:07 +0200 Message-ID: <87fr1sr6wc.ffs@fw13> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable On Wed, Jul 08 2026 at 18:53, Wu Frank wrote: > On Wed, Jul 8, 2026 at 6:04=E2=80=AFPM Sasha Levin wr= ote: >> Could you resend this as a two-patch series: this patch plus a 5.15.y >> adaptation of 40a25d59e85b3c? Also worth considering as a third patch is >> 74e144274af399 ("futex/requeue: Prevent NULL pointer dereference in >> remove_waiter() on self-deadlock"). > > For completeness, we also reviewed the related patches yesterday. > > Our understanding is that the correct backport set is this patch plus > 40a25d59e85b3c. This patch fixes the original issue, while > 40a25d59e85b3c fixes the NULL-pointer dereference. We also noticed > that 40a25d59e85b3c appears to cover a separate > use-before-initialization case, although that case is not relevant to > this backport. > > I do not think 74e144274af399 should be included. It was later > reverted by 39def6d250d3, and the revert changelog says that the issue > was already handled by 40a25d59e85b3c. It also notes that > 74e144274af399 introduced new problems. Only 40a25d59e85b3c needs to be backported. 74e144274af399 is not required and buggy and got reverted upstream. Thanks, tglx