From: Oliver Neukum <oneukum@suse.com>
To: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>,
Andrey Konovalov <andreyknvl@google.com>
Cc: Alan Stern <stern@rowland.harvard.edu>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Colin Ian King <colin.king@canonical.com>,
Arnd Bergmann <arnd@arndb.de>,
USB list <linux-usb@vger.kernel.org>,
syzbot <syzbot+854768b99f19e89d7f81@syzkaller.appspotmail.com>,
syzkaller-bugs <syzkaller-bugs@googlegroups.com>
Subject: Re: [PATCH] USB: cdc-wdm: Call wake_up_all() when clearing WDM_IN_USE bit.
Date: Thu, 02 Jul 2020 09:24:26 +0200 [thread overview]
Message-ID: <1593674666.3609.3.camel@suse.com> (raw)
In-Reply-To: <b347b882-a986-24c6-2b37-0b1a092931b9@i-love.sakura.ne.jp>
Am Donnerstag, den 02.07.2020, 14:44 +0900 schrieb Tetsuo Handa:
>
> usb_autopm_put_interface(desc->intf)
> mutex_unlock(&desc->wlock);
> + if (rv >= 0 &&
> + /*
> + * needs both flags. We cannot do with one
> + * because resetting it would cause a race
> + * with write() yet we need to signal
> + * a disconnect
> + */
> + wait_event_killable_timeout(desc->wait,
> + !test_bit(WDM_IN_USE, &desc->flags) ||
> + test_bit(WDM_DISCONNECTING, &desc->flags), 30 * HZ) == 0) {
> + if (mutex_lock_killable(&desc->wlock) == 0) {
> + if (!test_bit(WDM_DISCONNECTING, &desc->flags))
> + dev_err(&desc->intf->dev,
> + "Tx URB not responding index=%d\n",
> + le16_to_cpu(req->wIndex));
> + mutex_unlock(&desc->wlock);
> + }
> + }
Hi,
I am afraid this would
1. serialize the driver, harming performance
2. introduce a race with every timer a task is running
Regards
Oliver
next prev parent reply other threads:[~2020-07-02 7:24 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-20 23:31 [PATCH] USB: cdc-wdm: Call wake_up_all() when clearing WDM_IN_USE bit Tetsuo Handa
2020-05-21 7:33 ` Greg KH
2020-05-21 10:01 ` Tetsuo Handa
2020-05-21 19:50 ` Oliver Neukum
2020-05-21 22:48 ` Tetsuo Handa
2020-05-22 8:04 ` Oliver Neukum
2020-05-22 8:26 ` Tetsuo Handa
2020-05-25 12:06 ` Oliver Neukum
2020-05-25 13:32 ` Tetsuo Handa
2020-05-27 4:47 ` Tetsuo Handa
2020-05-28 15:18 ` Andrey Konovalov
2020-05-28 16:03 ` Tetsuo Handa
2020-05-28 19:03 ` Andrey Konovalov
2020-05-28 19:40 ` Alan Stern
2020-05-28 19:51 ` Andrey Konovalov
2020-05-28 20:58 ` Alan Stern
2020-05-29 20:41 ` Andrey Konovalov
2020-05-30 0:42 ` Tetsuo Handa
2020-05-30 1:10 ` Alan Stern
2020-05-30 4:58 ` Tetsuo Handa
2020-06-24 11:57 ` Oliver Neukum
2020-06-24 12:48 ` Tetsuo Handa
2020-05-30 6:08 ` Greg Kroah-Hartman
2020-06-01 12:26 ` Andrey Konovalov
2020-05-30 15:25 ` Oliver Neukum
2020-05-30 15:47 ` Alan Stern
2020-06-08 2:24 ` Tetsuo Handa
2020-06-18 0:48 ` Tetsuo Handa
2020-06-19 13:56 ` Andrey Konovalov
2020-06-23 11:20 ` Tetsuo Handa
2020-07-02 5:44 ` Tetsuo Handa
2020-07-02 7:24 ` Oliver Neukum [this message]
2020-07-15 6:15 ` Tetsuo Handa
2020-08-10 10:47 ` Tetsuo Handa
2020-09-24 15:09 ` [PATCH] USB: cdc-wdm: Make wdm_flush() interruptible and add wdm_fsync() Tetsuo Handa
2020-09-28 14:17 ` [PATCH (repost)] " Tetsuo Handa
2020-06-25 9:56 ` [PATCH] USB: cdc-wdm: Call wake_up_all() when clearing WDM_IN_USE bit Oliver Neukum
2020-06-25 11:15 ` Tetsuo Handa
2020-07-01 7:08 ` [TEST]Re: " Oliver Neukum
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