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 5E5B57B for ; Wed, 23 Nov 2022 08:54:57 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B7C98C433C1; Wed, 23 Nov 2022 08:54:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1669193697; bh=BpiMkt0Ka+oPJoqohNWa6CJreGbbQzrFG2TMvGhMeU0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=MApWeCOKAml+wcD77DeMRybfkBP+sUO6k3QkNhx096LfHmWNY4gCQVAbrvTqh3EJw H06YRYNhk/z4Pb9IgaV8aCyOx+bDi3Nt1Zi4xUMdBl9/5Gd4/Ppl8RTMyHDBh7teyg SBC6jwxCh3aQcpVo9kr7IbPNTGPZLNIrZhoSMq3k= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Duoming Zhou , Sasha Levin Subject: [PATCH 4.9 36/76] tty: n_gsm: fix sleep-in-atomic-context bug in gsm_control_send Date: Wed, 23 Nov 2022 09:50:35 +0100 Message-Id: <20221123084547.913047429@linuxfoundation.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221123084546.742331901@linuxfoundation.org> References: <20221123084546.742331901@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Duoming Zhou [ Upstream commit 7b7dfe4833c70a11cdfa51b38705103bd31eddaa ] The function gsm_dlci_t1() is a timer handler that runs in an atomic context, but it calls "kzalloc(..., GFP_KERNEL)" that may sleep. As a result, the sleep-in-atomic-context bug will happen. The process is shown below: gsm_dlci_t1() gsm_dlci_open() gsm_modem_update() gsm_modem_upd_via_msc() gsm_control_send() kzalloc(sizeof(.., GFP_KERNEL) //may sleep This patch changes the gfp_t parameter of kzalloc() from GFP_KERNEL to GFP_ATOMIC in order to mitigate the bug. Fixes: e1eaea46bb40 ("tty: n_gsm line discipline") Signed-off-by: Duoming Zhou Link: https://lore.kernel.org/r/20221002040709.27849-1-duoming@zju.edu.cn Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- drivers/tty/n_gsm.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c index 3badb10229ef..1131065a4ef3 100644 --- a/drivers/tty/n_gsm.c +++ b/drivers/tty/n_gsm.c @@ -1377,7 +1377,7 @@ static struct gsm_control *gsm_control_send(struct gsm_mux *gsm, unsigned int command, u8 *data, int clen) { struct gsm_control *ctrl = kzalloc(sizeof(struct gsm_control), - GFP_KERNEL); + GFP_ATOMIC); unsigned long flags; if (ctrl == NULL) return NULL; -- 2.35.1