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From: Oliver Neukum <oneukum@suse.com>
To: penguin-kernel@i-love.sakura.ne.jp, bjorn@mork.no,
	linux-usb@vger.kernel.org
Cc: Oliver Neukum <oneukum@suse.com>
Subject: [RFC 4/6] CDC-WDM: fix race reporting errors in flush
Date: Tue, 22 Sep 2020 12:13:27 +0200	[thread overview]
Message-ID: <20200922101329.14801-5-oneukum@suse.com> (raw)
In-Reply-To: <20200922101329.14801-1-oneukum@suse.com>

In case a race was lost and multiple fds used,
an error could be reported multiple times. To fix
this a spinlock must be taken.

Signed-off-by: Oliver Neukum <oneukum@suse.com>
---
 drivers/usb/class/cdc-wdm.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/usb/class/cdc-wdm.c b/drivers/usb/class/cdc-wdm.c
index 1ca2c85a977d..5fb855404403 100644
--- a/drivers/usb/class/cdc-wdm.c
+++ b/drivers/usb/class/cdc-wdm.c
@@ -613,7 +613,10 @@ static int wdm_flush(struct file *file, fl_owner_t id)
 	if (!rv)
 		return -EIO;
 
+	spin_lock_irq(&desc->iuspin);
 	rv = desc->werr;
+	desc->werr = 0;
+	spin_unlock_irq(&desc->iuspin);
 
 	return usb_translate_errors(rv);
 }
-- 
2.16.4


  parent reply	other threads:[~2020-09-22 10:13 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-22 10:13 [RFC] fixes for hangs and error reporting in CDC_WDM Oliver Neukum
2020-09-22 10:13 ` [RFC 1/6] CDC-WDM: fix hangs in flush() in multithreaded cases Oliver Neukum
2020-09-22 10:13 ` [RFC 2/6] CDC-WDM: introduce a timeout in flush() Oliver Neukum
2020-09-22 10:13 ` [RFC 3/6] CDC-WDM: remove use of intf->dev after potential disconnect Oliver Neukum
2020-09-22 10:13 ` Oliver Neukum [this message]
2020-09-22 10:13 ` [RFC 5/6] CDC-WDM: correct error reporting in write() Oliver Neukum
2020-09-22 10:13 ` [RFC 6/6] CDC-WDM: implement fsync Oliver Neukum
2020-09-22 10:42 ` [RFC] fixes for hangs and error reporting in CDC_WDM Tetsuo Handa
  -- strict thread matches above, loose matches on Subject: below --
2020-09-10 12:21 [RFC 1/6] CDC-WDM: fix hangs in flush() Oliver Neukum
2020-09-10 12:21 ` [RFC 4/6] CDC-WDM: fix race reporting errors in flush Oliver Neukum

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