From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C3CD0C64E75 for ; Tue, 17 Nov 2020 13:44:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7014B20729 for ; Tue, 17 Nov 2020 13:44:42 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="qrDl6Don" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732945AbgKQNky (ORCPT ); Tue, 17 Nov 2020 08:40:54 -0500 Received: from mail.kernel.org ([198.145.29.99]:52968 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732912AbgKQNkx (ORCPT ); Tue, 17 Nov 2020 08:40:53 -0500 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 23BB22465E; Tue, 17 Nov 2020 13:40:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1605620451; bh=DIjBjeDq1ZYRW5cBKZFmzvPfZeig4cQX54M4VKEqhAk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=qrDl6DonN7S1DNPgJHu/mZAqoWXT6KsoxVXvHUK4+6I7TwOWxXrCsXxiwXF6Xbp0l ZFHS/u9UAfTFIf4Mp4M7JBS4JI3+R8zi6CaDnE+BlyIdQQ5yIMjlsgAciHImDPnVFC 6sPVTcr270WpIW5srwO1eYUOBS5hNXp2XY0Fwd20= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jookia , Samuel Thibault Subject: [PATCH 5.9 194/255] speakup: Fix clearing selection in safe context Date: Tue, 17 Nov 2020 14:05:34 +0100 Message-Id: <20201117122148.372918687@linuxfoundation.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201117122138.925150709@linuxfoundation.org> References: <20201117122138.925150709@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Samuel Thibault commit 640969a69ca4dd2ac025fe873c6bf25eba8f11b3 upstream. speakup_cut() calls speakup_clear_selection() which calls console_lock. Problem is: speakup_cut() is called from a keyboard interrupt context. This would hang if speakup_cut is pressed while the console lock is unfortunately already held. We can however as well just defer calling clear_selection() until the already-deferred set_selection_kernel() call. This was spotted by the lock hardener: Possible unsafe locking scenario:\x0a CPU0 ---- lock(console_lock); lock(console_lock); \x0a *** DEADLOCK ***\x0a [...] Call Trace: dump_stack+0xc2/0x11a print_usage_bug.cold+0x3e0/0x4b1 mark_lock+0xd95/0x1390 ? print_irq_inversion_bug+0xa0/0xa0 __lock_acquire+0x21eb/0x5730 ? __kasan_check_read+0x11/0x20 ? check_chain_key+0x215/0x5e0 ? register_lock_class+0x1580/0x1580 ? lock_downgrade+0x7a0/0x7a0 ? __rwlock_init+0x140/0x140 lock_acquire+0x13f/0x370 ? speakup_clear_selection+0xe/0x20 [speakup] console_lock+0x33/0x50 ? speakup_clear_selection+0xe/0x20 [speakup] speakup_clear_selection+0xe/0x20 [speakup] speakup_cut+0x19e/0x4b0 [speakup] keyboard_notifier_call+0x1f04/0x4a40 [speakup] ? read_all_doc+0x240/0x240 [speakup] notifier_call_chain+0xbf/0x130 __atomic_notifier_call_chain+0x80/0x130 atomic_notifier_call_chain+0x16/0x20 kbd_event+0x7d7/0x3b20 ? k_pad+0x850/0x850 ? sysrq_filter+0x450/0xd40 input_to_handler+0x362/0x4b0 ? rcu_read_lock_sched_held+0xe0/0xe0 input_pass_values+0x408/0x5a0 ? __rwlock_init+0x140/0x140 ? lock_acquire+0x13f/0x370 input_handle_event+0x70e/0x1380 input_event+0x67/0x90 atkbd_interrupt+0xe62/0x1d4e [atkbd] ? __kasan_check_write+0x14/0x20 ? atkbd_event_work+0x130/0x130 [atkbd] ? _raw_spin_lock_irqsave+0x26/0x70 serio_interrupt+0x93/0x120 [serio] i8042_interrupt+0x232/0x510 [i8042] ? rcu_read_lock_bh_held+0xd0/0xd0 ? handle_irq_event+0xa5/0x13a ? i8042_remove+0x1f0/0x1f0 [i8042] __handle_irq_event_percpu+0xe6/0x6c0 handle_irq_event_percpu+0x71/0x150 ? __handle_irq_event_percpu+0x6c0/0x6c0 ? __kasan_check_read+0x11/0x20 ? do_raw_spin_unlock+0x5c/0x240 handle_irq_event+0xad/0x13a handle_edge_irq+0x233/0xa90 do_IRQ+0x10b/0x310 common_interrupt+0xf/0xf Cc: stable@vger.kernel.org Reported-by: Jookia Signed-off-by: Samuel Thibault Link: https://lore.kernel.org/r/20201107233310.7iisvaozpiqj3yvy@function Signed-off-by: Greg Kroah-Hartman --- drivers/accessibility/speakup/main.c | 1 - drivers/accessibility/speakup/selection.c | 11 ++++------- drivers/accessibility/speakup/speakup.h | 1 - 3 files changed, 4 insertions(+), 9 deletions(-) --- a/drivers/accessibility/speakup/main.c +++ b/drivers/accessibility/speakup/main.c @@ -357,7 +357,6 @@ static void speakup_cut(struct vc_data * mark_cut_flag = 0; synth_printf("%s\n", spk_msg_get(MSG_CUT)); - speakup_clear_selection(); ret = speakup_set_selection(tty); switch (ret) { --- a/drivers/accessibility/speakup/selection.c +++ b/drivers/accessibility/speakup/selection.c @@ -22,13 +22,6 @@ struct speakup_selection_work { struct tty_struct *tty; }; -void speakup_clear_selection(void) -{ - console_lock(); - clear_selection(); - console_unlock(); -} - static void __speakup_set_selection(struct work_struct *work) { struct speakup_selection_work *ssw = @@ -51,6 +44,10 @@ static void __speakup_set_selection(stru goto unref; } + console_lock(); + clear_selection(); + console_unlock(); + set_selection_kernel(&sel, tty); unref: --- a/drivers/accessibility/speakup/speakup.h +++ b/drivers/accessibility/speakup/speakup.h @@ -70,7 +70,6 @@ void spk_do_flush(void); void speakup_start_ttys(void); void synth_buffer_add(u16 ch); void synth_buffer_clear(void); -void speakup_clear_selection(void); int speakup_set_selection(struct tty_struct *tty); void speakup_cancel_selection(void); int speakup_paste_selection(struct tty_struct *tty);