From: Hillf Danton <hdanton@sina.com>
To: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: syzbot <syzbot+06fa1063cca8163ea541@syzkaller.appspotmail.com>,
syzkaller-bugs@googlegroups.com,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Jiri Slaby <jirislaby@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
linux-kernel@vger.kernel.org,
linux-serial <linux-serial@vger.kernel.org>
Subject: Re: [PATCH] tty: vt: check for atomic context in con_write()
Date: Sun, 21 Jan 2024 11:48:17 +0800 [thread overview]
Message-ID: <20240121034817.2280-1-hdanton@sina.com> (raw)
In-Reply-To: <9cd9d3eb-418f-44cc-afcf-7283d51252d6@I-love.SAKURA.ne.jp>
On Sat, 20 Jan 2024 19:34:02 +0900 Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
> syzbot is reporting sleep in atomic context, for gsmld_write() is calling
> con_write() with spinlock held and IRQs disabled.
...
> --- a/drivers/tty/vt/vt.c
> +++ b/drivers/tty/vt/vt.c
> @@ -2856,7 +2856,7 @@ static int do_con_write(struct tty_struct *tty, const u8 *buf, int count)
> struct vt_notifier_param param;
> bool rescan;
>
> - if (in_interrupt())
> + if (in_interrupt() || irqs_disabled())
> return count;
>
> console_lock();
Given console_lock(), no sense could be made by calling do_con_write()
with spin lock held at the first place, regardless irq.
> @@ -3314,7 +3314,7 @@ static void con_flush_chars(struct tty_struct *tty)
> {
> struct vc_data *vc;
>
> - if (in_interrupt()) /* from flush_to_ldisc */
> + if (in_interrupt() || irqs_disabled()) /* from flush_to_ldisc */
> return;
>
> /* if we race with con_close(), vt may be null */
> --
> 2.18.4
next prev parent reply other threads:[~2024-01-21 3:48 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-01-18 9:51 [syzbot] [dri?] BUG: scheduling while atomic in drm_atomic_helper_wait_for_flip_done syzbot
2024-01-18 14:18 ` Tetsuo Handa
2024-01-20 10:34 ` [PATCH] tty: vt: check for atomic context in con_write() Tetsuo Handa
2024-01-21 3:48 ` Hillf Danton [this message]
2024-01-21 11:34 ` Tetsuo Handa
2024-01-22 6:48 ` Jiri Slaby
2024-01-22 14:08 ` Tetsuo Handa
2024-01-24 10:06 ` [PATCH] tty: n_gsm: restrict tty devices to attach Tetsuo Handa
2024-01-24 13:14 ` Greg Kroah-Hartman
2024-02-03 13:45 ` Tetsuo Handa
2024-02-06 14:28 ` Greg Kroah-Hartman
2024-04-20 11:17 ` [syzbot] [dri?] BUG: scheduling while atomic in drm_atomic_helper_wait_for_flip_done Tetsuo Handa
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