diff options
| author | Oliver Neukum <oneukum@suse.com> | 2019-08-08 16:21:19 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-08-25 10:53:02 +0200 |
| commit | 8fed007578dba671e131781360dd87c4683672e7 (patch) | |
| tree | ca063014dc613dc6220bf87a370f2ec22d0e0ccb /drivers/usb/class/cdc-acm.c | |
| parent | 8f67bc7c8da8622fddf4d29a2f422678dfbadf77 (diff) | |
usb: cdc-acm: make sure a refcount is taken early enough
commit c52873e5a1ef72f845526d9f6a50704433f9c625 upstream.
destroy() will decrement the refcount on the interface, so that
it needs to be taken so early that it never undercounts.
Fixes: 7fb57a019f94e ("USB: cdc-acm: Fix potential deadlock (lockdep warning)")
Cc: stable <stable@vger.kernel.org>
Reported-and-tested-by: syzbot+1b2449b7b5dc240d107a@syzkaller.appspotmail.com
Signed-off-by: Oliver Neukum <oneukum@suse.com>
Link: https://lore.kernel.org/r/20190808142119.7998-1-oneukum@suse.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/usb/class/cdc-acm.c')
| -rw-r--r-- | drivers/usb/class/cdc-acm.c | 18 |
1 files changed, 10 insertions, 8 deletions
diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c index 736de1021d8b..1930a8ec4b67 100644 --- a/drivers/usb/class/cdc-acm.c +++ b/drivers/usb/class/cdc-acm.c @@ -1319,13 +1319,6 @@ made_compressed_probe: if (acm == NULL) goto alloc_fail; - minor = acm_alloc_minor(acm); - if (minor < 0) { - dev_err(&intf->dev, "no more free acm devices\n"); - kfree(acm); - return -ENODEV; - } - ctrlsize = usb_endpoint_maxp(epctrl); readsize = usb_endpoint_maxp(epread) * (quirks == SINGLE_RX_URB ? 1 : 2); @@ -1333,6 +1326,16 @@ made_compressed_probe: acm->writesize = usb_endpoint_maxp(epwrite) * 20; acm->control = control_interface; acm->data = data_interface; + + usb_get_intf(acm->control); /* undone in destruct() */ + + minor = acm_alloc_minor(acm); + if (minor < 0) { + dev_err(&intf->dev, "no more free acm devices\n"); + kfree(acm); + return -ENODEV; + } + acm->minor = minor; acm->dev = usb_dev; acm->ctrl_caps = ac_management_function; @@ -1474,7 +1477,6 @@ skip_countries: usb_driver_claim_interface(&acm_driver, data_interface, acm); usb_set_intfdata(data_interface, acm); - usb_get_intf(control_interface); tty_dev = tty_port_register_device(&acm->port, acm_tty_driver, minor, &control_interface->dev); if (IS_ERR(tty_dev)) { |