Re: kernel BUG in new r8188eu

Larry Finger
2021-07-31T21:57:57Z

On 7/31/21 1:53 PM, Fabio Aiuto wrote:
> Hi all,
>
> On Sat, Jul 31, 2021 at 11:18:10AM -0500, Larry Finger wrote:
>> On 7/31/21 12:37 AM, Greg Kroah-Hartman wrote:
>>> Is this a new regression due to the recent cleanups, or something that
>>> has always been here?
>>
>> I suspect that it has been there forever. I was just doing the kinds of
>> things a user might do, and locked up my box.
>>
>>> As for the error, looks like someone is reading to an address that is
>>> in userspace without doing the proper copy_from_user() thing. Do you
>>> have a full traceback?
>>
>> BUG: unable to handle page fault for address: ffffeb020003b848
>> #PF: supervisor read access in kernel mode
>> #PF: error_code(0x0000) - not-present page
>> PGD 0 P4D 0
>> Oops: 0000 [#1] SMP PTI
>> CPU: 2 PID: 45 Comm: kworker/2:1 Tainted: G C O
>> 5.14.0-rc2-00157-g390c661543a8 #8
>> Hardware name: TOSHIBA TECRA A50-A/TECRA A50-A, BIOS Version 4.50 09/29/2014
>> Workqueue: usb_hub_wq hub_event [usbcore]
>> RIP: 0010:kfree+0x68/0x2c0
>> Code: 01 e5 0f 82 5f 02 00 00 48 b8 00 00 00 80 7f 77 00 00 48 01 c5 48 b8
>> 00 00 00 00 00 ea ff ff 48 c1 ed 0c 48 c1 e5 06 48 01 c5 <48> 8b 45 0>
>> RSP: 0018:ffffc900001efa78 EFLAGS: 00010282
>> RAX: ffffea0000000000 RBX: ffffc90000ee1028 RCX: 000000008010000d
>> RDX: 0000000000000000 RSI: ffffffffa149eddf RDI: ffffc90000ee1578
>> RBP: ffffeb020003b840 R08: 0000000000000001 R09: 0000000000000001
>> R10: 0000000000000000 R11: ffff888121c0e400 R12: ffffc90000ee1578
>> R13: ffff888101fd0000 R14: ffff888101fd0030 R15: 0000000000000003
>> FS: 0000000000000000(0000) GS:ffff888323280000(0000) knlGS:0000000000000000
>> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>> CR2: ffffeb020003b848 CR3: 000000000220a002 CR4: 00000000001706e0
>> Call Trace:
>> ? kfree+0x25a/0x2c0
>> rtw_free_mlme_priv_ie_data+0x15/0xf8 [r8188eu]
>> _rtw_free_mlme_priv+0xe/0x30 [r8188eu]
>> rtw_free_mlme_priv+0x1a/0x47 [r8188eu]
>> rtw_free_drv_sw+0x5c/0x1ae [r8188eu]
>> rtw_usb_if1_deinit+0x67/0xcd [r8188eu]
>> rtw_dev_remove+0x5a/0xf4 [r8188eu]
>> usb_unbind_interface+0x8a/0x270 [usbcore]
>> ? kernfs_find_ns+0x35/0xd0
>> __device_release_driver+0x1a0/0x260
>> device_release_driver+0x24/0x30
>> bus_remove_device+0xd8/0x140
>> device_del+0x18b/0x3e0
>> ? kobject_cleanup+0x49/0x130
>> usb_disable_device+0xd9/0x260 [usbcore]
>> usb_disconnect.cold+0x7b/0x201 [usbcore]
>> hub_port_connect+0x88/0x8d0 [usbcore]
>> ? kfree+0xe6/0x2c0
>> hub_port_connect_change+0xb1/0x3a0 [usbcore]
>> port_event+0x5d4/0x720 [usbcore]
>> hub_event+0x1db/0x430 [usbcore]
>> process_one_work+0x1dd/0x3a0
>> worker_thread+0x50/0x3f0
>> ? rescuer_thread+0x390/0x390
>> kthread+0x128/0x140
>> ? set_kthread_struct+0x40/0x40
>> ret_from_fork+0x22/0x30
>> Modules linked in: snd_seq_dummy snd_hrtimer snd_seq snd_seq_device ctr ccm
>> r8188eu(C) rfcomm rpcsec_gss_krb5 auth_rpcgss nfsv4 dns_resolver nfs>
>> crypto_simd cryptd i915 i2c_algo_bit serio_raw ttm drm_kms_helper
>> syscopyarea sysfillrect sysimgblt fb_sys_fops drm xhci_pci ehci_pci xhci_hcd
>>>
>> CR2: ffffeb020003b848
>> ---[ end trace f5f4e2b2680b5fd7 ]---
>>
>> The driver is allocating some buffers using kmalloc variants, and others
>> using vmalloc. I checked to see if there was confusion on which form of free
>> should be used, but this one is allocated with kmalloc and freed with kfree,
>> which should be OK.
>>
>> Larry
>>
>
> Maybe hostapd is involved. Try killing hostapd before and then
> unplug the dongle... does the system freeze?
>
> #include "../include/rtw_android.h"
> int rtw_ioctl(struct net_device *dev, struct ifreq *rq, int cmd)
> {
> struct iwreq *wrq = (struct iwreq *)rq;
> int ret = 0;
>
> switch (cmd) {
> case RTL_IOCTL_WPA_SUPPLICANT:
> ret = wpa_supplicant_ioctl(dev, &wrq->u.data);
> break;
> #ifdef CONFIG_88EU_AP_MODE
> case RTL_IOCTL_HOSTAPD:
> ret = rtw_hostapd_ioctl(dev, &wrq->u.data);
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>
> I think that someone tries to write the wrong fields while
> freeing memory...
>
> break;
> #endif /* CONFIG_88EU_AP_MODE */
> case SIOCDEVPRIVATE:
>
> static int rtw_hostapd_ioctl(struct net_device *dev, struct iw_point *p)
> {
> struct ieee_param *param;
> int ret = 0;
> struct adapter *padapter = (struct adapter *)rtw_netdev_priv(dev);
>
> ...
>
> switch (param->cmd) {
> case RTL871X_HOSTAPD_FLUSH:
> ret = rtw_hostapd_sta_flush(dev);
> break;
> ...
> case RTL871X_HOSTAPD_SET_WPS_BEACON:
> ret = rtw_set_wps_beacon(dev, param, p->length);
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> break;
>
> static int rtw_set_wps_beacon(struct net_device *dev, struct ieee_param *param, int len)
> {
> int ret = 0;
>
> ...
>
> memcpy(pmlmepriv->wps_beacon_ie, param->u.bcn_ie.buf, ie_len);
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> maybe hotsapd does some ioctl at the wrong moment.
>
> Just to verify, we could kill hostapd, if ever runs in your machine...

No, hostapd was not involved. I was using r8188eu in STA mode.

Larry