From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793209005; b=RHq2oMR2qJWiyuFE+WrttXd5xruQq6sbBtxAwgbuXknYj4ttEyDeMdE9j9HM9km91NsR 7Y1pbZ5xqm2Nr8KE0Z/MoLkD7RMS/WXHVBV9siYLXW35IJcNQT9xx2BysnnGP7HBI99Uc xY9lsVbShU6Z+gwv8xEwL7CSEDa/2g7ZFVW4+NvNcxaRkFXBHDBxY1g4tRpzT5TGvB/Pg dFVqeovoATmvens8PXanD6dKnKXcOsZTRAcffflGR+DlLv9Zic5RyNeNc14wSFGdC8i1w +WefbKnVA+Cpud2qZz9POkTVPxfboVJdMeuzqmx2KnFiJDy7LUfmLuvQrXLy0GajF7w== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793209005; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=GfhKEo3CkCLW+MHsXp6lK69vrsIJZmeGlJ7j7E85NEg=; b=2t1DXbyA0XVEU9xTatQhsQUFnlaoMMWyBx/DGNgr0fhdy8S7iRUX/dqUKRGRDoIl5sxv cislt0apnjWgFLU1NKFheVFnQtFxQjT2OPGUiBbcaIWbvDRaNV38+Zk47ZqRBPBvkndvV gdlyaiE0ziPqM+6XJWd9eEKiSgCI4eN5CbgGxh9rlDg+njF5FVgkcR86VRv8s2yW7teP+ baGlHCMIVCuB/XTnIezmFcYM0LtuW7dwScX9V+CwO5iY8le6zDEaFbigkijbjPOAw/kqp 7P6pT5KKOJBrgdjw0j3uSSABefZMz2em8XeYPRnIurlqlkp7H8hEOVX8FRygyDj9jGQ== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=2C8NGFxj; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 60E05606A31D; Wed, 28 Oct 2026 17:36:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=2C8NGFxj Received: by smtp.kernel.org (Postfix) with ESMTPSA id B04911F01825; Wed, 28 Oct 2026 17:36:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1793209005; bh=GfhKEo3CkCLW+MHsXp6lK69vrsIJZmeGlJ7j7E85NEg=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=2C8NGFxjAAqWZN8/yGTbmH2GEk6Fvz9ZgbQGqcVrq0ZSy4y2oJC0b2sXXb2fkRmWh +2SE97cK5c4iOtvcNhiSvCLyRtb8ZVYbPeKWAsvnOg9crGYMXzRfzpjfAQ+BQfWSKW gtE4qZ/tL3wzsX3JugAdRdVflK/bz5YfzU+2+2UU= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Pavankumar Kondeti , Tejun Heo Subject: [PATCH 5.10 318/516] workqueue: Fix NULL current_pwq deref in chained work check Date: Wed, 28 Oct 2026 17:57:50 +0100 Message-ID: <20261028170011.023453303@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261028170003.522232767@linuxfoundation.org> References: <20261028170003.522232767@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: patches@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Pavankumar Kondeti commit 980db94e3eeefdd8a1c46f86412c33a7f7806f51 upstream. current_wq_worker() only tells us that %current is a kworker. It does not guarantee that the worker is currently executing a work item, as worker->current_pwq is populated only while process_one_work() is running the work function. is_chained_work() can be reached while queueing on a draining or destroying workqueue. If a kworker outside work-item execution reaches that path, current_wq_worker() returns a worker but worker->current_pwq is NULL, and the chained-work test can fault before it emits the intended warning. Guard the chained-work test with worker->current_pwq. A kworker without current_pwq is not executing work on the target workqueue, so the helper should return false and let the draining/destroying warning fire. Fixes: 8d03ecfe4718 ("workqueue: reimplement is_chained_work() using current_wq_worker()") Cc: stable@vger.kernel.org Signed-off-by: Pavankumar Kondeti Signed-off-by: Tejun Heo Signed-off-by: Greg Kroah-Hartman --- kernel/workqueue.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -1369,7 +1369,7 @@ static bool is_chained_work(struct workq * Return %true iff I'm a worker executing a work item on @wq. If * I'm @worker, it's safe to dereference it without locking. */ - return worker && worker->current_pwq->wq == wq; + return worker && worker->current_pwq && worker->current_pwq->wq == wq; } /*