• Takashi Iwai's avatar
    [media] uvcvideo: Fix destruction order in uvc_delete() · 2228d80d
    Takashi Iwai authored
    We've got a bug report at disconnecting a Webcam, where the kernel
    spews warnings like below:
      WARNING: CPU: 0 PID: 8385 at ../fs/sysfs/group.c:219 sysfs_remove_group+0x87/0x90()
      sysfs group c0b2350c not found for kobject 'event3'
      CPU: 0 PID: 8385 Comm: queue2:src Not tainted 3.16.2-1.gdcee397-default #1
      Hardware name: ASUSTeK Computer INC. A7N8X-E/A7N8X-E, BIOS ASUS A7N8X-E Deluxe ACPI BIOS Rev 1013  11/12/2004
        c08d0705 ddc75cbc c0718c5b ddc75ccc c024b654 c08c6d44 ddc75ce8 000020c1
        c08d0705 000000db c03d1ec7 c03d1ec7 00000009 00000000 c0b2350c d62c9064
        ddc75cd4 c024b6a3 00000009 ddc75ccc c08c6d44 ddc75ce8 ddc75cfc c03d1ec7
      Call Trace:
        [<c0205ba6>] try_stack_unwind+0x156/0x170
        [<c02046f3>] dump_trace+0x53/0x180
        [<c0205c06>] show_trace_log_lvl+0x46/0x50
        [<c0204871>] show_stack_log_lvl+0x51/0xe0
        [<c0205c67>] show_stack+0x27/0x50
        [<c0718c5b>] dump_stack+0x3e/0x4e
        [<c024b654>] warn_slowpath_common+0x84/0xa0
        [<c024b6a3>] warn_slowpath_fmt+0x33/0x40
        [<c03d1ec7>] sysfs_remove_group+0x87/0x90
        [<c05a2c54>] device_del+0x34/0x180
        [<c05e3989>] evdev_disconnect+0x19/0x50
        [<c05e06fa>] __input_unregister_device+0x9a/0x140
        [<c05e0845>] input_unregister_device+0x45/0x80
        [<f854b1d6>] uvc_delete+0x26/0x110 [uvcvideo]
        [<f84d66f8>] v4l2_device_release+0x98/0xc0 [videodev]
        [<c05a25bb>] device_release+0x2b/0x90
        [<c04ad8bf>] kobject_cleanup+0x6f/0x1a0
        [<f84d5453>] v4l2_release+0x43/0x70 [videodev]
        [<c0372f31>] __fput+0xb1/0x1b0
        [<c02650c1>] task_work_run+0x91/0xb0
        [<c024d845>] do_exit+0x265/0x910
        [<c024df64>] do_group_exit+0x34/0xa0
        [<c025a76f>] get_signal_to_deliver+0x17f/0x590
        [<c0201b6a>] do_signal+0x3a/0x960
        [<c02024f7>] do_notify_resume+0x67/0x90
        [<c071ebb5>] work_notifysig+0x30/0x3b
        [<b7739e60>] 0xb7739e5f
       ---[ end trace b1e56095a485b631 ]---
    
    The cause is that uvc_status_cleanup() is called after usb_put_*() in
    uvc_delete().  usb_put_*() removes the sysfs parent and eventually
    removes the children recursively, so the later device_del() can't find
    its sysfs.  The fix is simply rearrange the call orders in
    uvc_delete() so that the child is removed before the parent.
    
    Bugzilla: https://bugzilla.suse.com/show_bug.cgi?id=897736Reported-and-tested-by: default avatarMartin Pluskal <mpluskal@suse.com>
    
    Cc: <stable@vger.kernel.org>
    Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
    Signed-off-by: default avatarLaurent Pinchart <laurent.pinchart@ideasonboard.com>
    Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@osg.samsung.com>
    2228d80d
uvc_driver.c 68.7 KB