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 4B2C72E659; Tue, 8 Jul 2025 16:28:17 +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=1751992097; cv=none; b=mm8i2W3CoilFAHbanptziELsttCpCwQ+pGRV+L/2N3Oquj749aDcf9Z9LU6Q/Tc/wuuU0JMEaTDrm2Qu1RcP/KaPguxLn5+rwRw8rkfBWaCnceMBkkkQZ/Q8DRW4REQPXuOaa7w0416vaQp6AFm6Ege5W42t3gnvJGIVVr4z4T8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751992097; c=relaxed/simple; bh=QVLwFWqJReJc9uiYe0GcRacMnXtix6B2IXh98YZwIZk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=e0e53hpN/ETaftC4xW7ICrzPofsv5pjKpWCmh5xxPLjEIlrw11m+056mISGk3XB3iGMHJtmyMagECQKGWot33S4iAflOrl/f5FAkEwFPqU38By5zESH99YUhBgDmtrMEHp64xhL70gGyD7BkrOqZoirqwiCcBWM3Z8GMuNe8ze8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=nPt5g0R0; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="nPt5g0R0" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C50AEC4CEED; Tue, 8 Jul 2025 16:28:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1751992097; bh=QVLwFWqJReJc9uiYe0GcRacMnXtix6B2IXh98YZwIZk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=nPt5g0R0VCiDkwB1AlVB1v6WpVyUoG/Kz311pbKOGeNAN1mtgu0djbbt7XSgl+6Mg KWqSHnxV04sF9PRhYmT5zbV0Zf77wHowUZXy5apoqrS/gDRKetgV6rgh2Ahs545cSG BuzwqouUWs6IL0p7HMg5EWJb3JyruJQrREUCXG8Q= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, "Uladzislau Rezki (Sony)" , Joel Fernandes , Sasha Levin Subject: [PATCH 6.1 58/81] rcu: Return early if callback is not specified Date: Tue, 8 Jul 2025 18:23:50 +0200 Message-ID: <20250708162226.835204194@linuxfoundation.org> X-Mailer: git-send-email 2.50.0 In-Reply-To: <20250708162224.795155912@linuxfoundation.org> References: <20250708162224.795155912@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Uladzislau Rezki (Sony) [ Upstream commit 33b6a1f155d627f5bd80c7485c598ce45428f74f ] Currently the call_rcu() API does not check whether a callback pointer is NULL. If NULL is passed, rcu_core() will try to invoke it, resulting in NULL pointer dereference and a kernel crash. To prevent this and improve debuggability, this patch adds a check for NULL and emits a kernel stack trace to help identify a faulty caller. Signed-off-by: Uladzislau Rezki (Sony) Reviewed-by: Joel Fernandes Signed-off-by: Joel Fernandes Signed-off-by: Sasha Levin --- kernel/rcu/tree.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index dd6e15ca63b0c..38ab28a53e108 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -2827,6 +2827,10 @@ void call_rcu(struct rcu_head *head, rcu_callback_t func) /* Misaligned rcu_head! */ WARN_ON_ONCE((unsigned long)head & (sizeof(void *) - 1)); + /* Avoid NULL dereference if callback is NULL. */ + if (WARN_ON_ONCE(!func)) + return; + if (debug_rcu_head_queue(head)) { /* * Probable double call_rcu(), so leak the callback. -- 2.39.5