diff options
author | Oliver Neukum <oneukum@suse.com> | 2019-08-08 17:21:19 +0300 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-08-25 11:50:20 +0300 |
commit | e630f38040b5d2ecc56920742f7bafd57834cd2a (patch) | |
tree | 469e20c190d81feaf5c6f3fbde0d0790fa6859fe | |
parent | 56a3eb5fa5d024794c5c62edc0e7b5864aa68bcb (diff) | |
download | linux-e630f38040b5d2ecc56920742f7bafd57834cd2a.tar.xz |
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>
-rw-r--r-- | drivers/usb/class/cdc-acm.c | 12 |
1 files changed, 7 insertions, 5 deletions
diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c index efa8b620fee8..0453f0eb1178 100644 --- a/drivers/usb/class/cdc-acm.c +++ b/drivers/usb/class/cdc-acm.c @@ -1342,10 +1342,6 @@ made_compressed_probe: if (acm == NULL) goto alloc_fail; - minor = acm_alloc_minor(acm); - if (minor < 0) - goto alloc_fail1; - ctrlsize = usb_endpoint_maxp(epctrl); readsize = usb_endpoint_maxp(epread) * (quirks == SINGLE_RX_URB ? 1 : 2); @@ -1353,6 +1349,13 @@ 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) + goto alloc_fail1; + acm->minor = minor; acm->dev = usb_dev; if (h.usb_cdc_acm_descriptor) @@ -1501,7 +1504,6 @@ 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)) { |