Hi, looking at your last patch I noticed something. I think it fails to work if we hit a peculiar race condition. It looks to me like we can get the following: task A pre_reset() --> calling scsi_block_requests() task B shutdown() --> setting the shutdown flag post_reset() --> checking the flag -> do nothing -> deadlock So we need in addition something like the below patch. What do you think? Regards Oliver >From 68cc8940d7dde8e2a48217d8086cd692809e7980 Mon Sep 17 00:00:00 2001 From: Oliver Neukum <oneukum@xxxxxxxx> Date: Mon, 15 Jan 2018 13:56:59 +0100 Subject: [PATCH] UAS: fix race between post_reset() and shutdown() Disconnect due to shutdown can happen after pre_reset() has been called. Thus the host must be unblocked even in the shutdown case. Signed-off-by: Oliver Neukum <oneukum@xxxxxxxx> --- drivers/usb/storage/uas.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/usb/storage/uas.c b/drivers/usb/storage/uas.c index 338133a239df..d5ed1e581fb5 100644 --- a/drivers/usb/storage/uas.c +++ b/drivers/usb/storage/uas.c @@ -1046,10 +1046,11 @@ static int uas_post_reset(struct usb_interface *intf) struct Scsi_Host *shost = usb_get_intfdata(intf); struct uas_dev_info *devinfo = (struct uas_dev_info *)shost->hostdata; unsigned long flags; - int err; + int err = 1; + /* We may have lost the race and shutdown after pre_reset() */ if (devinfo->shutdown) - return 0; + goto skip; err = uas_configure_endpoints(devinfo); if (err && err != ENODEV) @@ -1062,6 +1063,7 @@ static int uas_post_reset(struct usb_interface *intf) scsi_report_bus_reset(shost, 0); spin_unlock_irqrestore(shost->host_lock, flags); +skip: scsi_unblock_requests(shost); return err ? 1 : 0; -- 2.13.6 -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
