This is a note to let you know that I've just added the patch titled usb: hub: Fix locking issues with address0_mutex to the 5.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: usb-hub-fix-locking-issues-with-address0_mutex.patch and it can be found in the queue-5.15 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 6cca13de26eea6d32a98d96d916a048d16a12822 Mon Sep 17 00:00:00 2001 From: Mathias Nyman <mathias.nyman@xxxxxxxxxxxxxxx> Date: Tue, 23 Nov 2021 12:16:56 +0200 Subject: usb: hub: Fix locking issues with address0_mutex From: Mathias Nyman <mathias.nyman@xxxxxxxxxxxxxxx> commit 6cca13de26eea6d32a98d96d916a048d16a12822 upstream. Fix the circular lock dependency and unbalanced unlock of addess0_mutex introduced when fixing an address0_mutex enumeration retry race in commit ae6dc22d2d1 ("usb: hub: Fix usb enumeration issue due to address0 race") Make sure locking order between port_dev->status_lock and address0_mutex is correct, and that address0_mutex is not unlocked in hub_port_connect "done:" codepath which may be reached without locking address0_mutex Fixes: 6ae6dc22d2d1 ("usb: hub: Fix usb enumeration issue due to address0 race") Cc: <stable@xxxxxxxxxxxxxxx> Reported-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx> Tested-by: Hans de Goede <hdegoede@xxxxxxxxxx> Tested-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx> Acked-by: Hans de Goede <hdegoede@xxxxxxxxxx> Signed-off-by: Mathias Nyman <mathias.nyman@xxxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20211123101656.1113518-1-mathias.nyman@xxxxxxxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/usb/core/hub.c | 20 ++++++++++++-------- 1 file changed, 12 insertions(+), 8 deletions(-) --- a/drivers/usb/core/hub.c +++ b/drivers/usb/core/hub.c @@ -5188,6 +5188,7 @@ static void hub_port_connect(struct usb_ struct usb_port *port_dev = hub->ports[port1 - 1]; struct usb_device *udev = port_dev->child; static int unreliable_port = -1; + bool retry_locked; /* Disconnect any existing devices under this port */ if (udev) { @@ -5244,10 +5245,10 @@ static void hub_port_connect(struct usb_ status = 0; - mutex_lock(hcd->address0_mutex); - for (i = 0; i < PORT_INIT_TRIES; i++) { - + usb_lock_port(port_dev); + mutex_lock(hcd->address0_mutex); + retry_locked = true; /* reallocate for each attempt, since references * to the previous one can escape in various ways */ @@ -5255,6 +5256,8 @@ static void hub_port_connect(struct usb_ if (!udev) { dev_err(&port_dev->dev, "couldn't allocate usb_device\n"); + mutex_unlock(hcd->address0_mutex); + usb_unlock_port(port_dev); goto done; } @@ -5276,13 +5279,13 @@ static void hub_port_connect(struct usb_ } /* reset (non-USB 3.0 devices) and get descriptor */ - usb_lock_port(port_dev); status = hub_port_init(hub, udev, port1, i); - usb_unlock_port(port_dev); if (status < 0) goto loop; mutex_unlock(hcd->address0_mutex); + usb_unlock_port(port_dev); + retry_locked = false; if (udev->quirks & USB_QUIRK_DELAY_INIT) msleep(2000); @@ -5372,11 +5375,14 @@ static void hub_port_connect(struct usb_ loop_disable: hub_port_disable(hub, port1, 1); - mutex_lock(hcd->address0_mutex); loop: usb_ep0_reinit(udev); release_devnum(udev); hub_free_dev(udev); + if (retry_locked) { + mutex_unlock(hcd->address0_mutex); + usb_unlock_port(port_dev); + } usb_put_dev(udev); if ((status == -ENOTCONN) || (status == -ENOTSUPP)) break; @@ -5399,8 +5405,6 @@ loop: } done: - mutex_unlock(hcd->address0_mutex); - hub_port_disable(hub, port1, 1); if (hcd->driver->relinquish_port && !hub->hdev->parent) { if (status != -ENOTCONN && status != -ENODEV) Patches currently in stable-queue which might be from mathias.nyman@xxxxxxxxxxxxxxx are queue-5.15/usb-hub-fix-locking-issues-with-address0_mutex.patch queue-5.15/usb-hub-fix-usb-enumeration-issue-due-to-address0-race.patch