[Bug 216543] kernel NULL pointer dereference usb_hcd_alloc_bandwidth

[bugzilla-daemon@kernel.org]

https://bugzilla.kernel.org/show_bug.cgi?id=216543

--- Comment #1 from gregkh@linuxfoundation.org ---
On Thu, Sep 29, 2022 at 06:53:46PM +0000, bugzilla-daemon@kernel.org wrote:
> With a flaky USB 3.0 cable (3m extension + 2m cable + 90 degree adapter) and
> Logitech BRIO webcam I got exactly the same null pointer dereference twice
> already.

That's really an unstable and unsupported system, sorry.  If you fix
your cable it should work properly, right?

> Here are two instances (from different boots):
> [64977.148098] BUG: kernel NULL pointer dereference, address:
> 0000000000000000
> [64977.148101] #PF: supervisor read access in kernel mode
> [64977.148102] #PF: error_code(0x0000) - not-present page
> [64977.148103] PGD 101370067 P4D 101370067 PUD 0
> [64977.148105] Oops: 0000 [#1] SMP NOPTI
> [64977.148107] CPU: 14 PID: 27951 Comm: VideoCapture Not tainted
> 5.19.10-xanmod1-x64v2 #0~20220920.git017c598

What about any kernel log messages from right before this crashed?
There should be some disconnect or other USB messages, right?  Specifics
here would be good to see.


> [64977.148109] Hardware name: Gigabyte Technology Co., Ltd. B550 VISION
> D/B550
> VISION D, BIOS F15d 07/20/2022
> [64977.148109] RIP: 0010:usb_ifnum_to_if+0x34/0x60
> [64977.148113] Code: 74 33 0f b6 4a 04 84 c9 74 33 83 e9 01 48 8d 82 98 00 00
> 00 48 8d bc ca a0 00 00 00 eb 09 48 83 c0 08 48 39 f8 74 16 48 8b 10 <48> 8b
> 0a
> 0f b6 49 02 39 f1 75 e9 48 89 d0 c3 cc cc cc cc 31 d2 48
> [64977.148114] RSP: 0018:ffffb20951407bb0 EFLAGS: 00010202
> [64977.148115] RAX: ffff8cfbbc618098 RBX: ffff8ceb844cc800 RCX:
> 0000000000000004
> [64977.148116] RDX: 0000000000000000 RSI: 0000000000000001 RDI:
> ffff8cfbbc6180c0
> [64977.148117] RBP: 0000000000000000 R08: 0000000080000000 R09:
> ffffffff8f590de8
> [64977.148117] R10: 0000000000000001 R11: 0000000000000001 R12:
> ffff8cf67c70f398
> [64977.148118] R13: 0000000000000000 R14: ffff8cf67c70f208 R15:
> ffff8ceb8123c000
> [64977.148119] FS:  00007f5f51379640(0000) GS:ffff8d0a3ed80000(0000)
> knlGS:0000000000000000
> [64977.148120] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [64977.148120] CR2: 0000000000000000 CR3: 000000023b842000 CR4:
> 0000000000750ee0
> [64977.148121] PKRU: 55555554
> [64977.148122] Call Trace:
> [64977.148123]  <TASK>
> [64977.148124]  usb_hcd_alloc_bandwidth+0x241/0x360
> [64977.148127]  usb_set_interface+0x11d/0x340
> [64977.148130]  uvc_video_start_transfer+0x17b/0x4b0 [uvcvideo]

This isn't good, we shouldn't crash when a device is removed, but this
might be an issue with some reference counting.  More log messages might
help out here.

thanks,

greg k-h

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