Hi, Thanks for reporting this! On 07/08/2012 06:25 PM, Frank Schäfer wrote: > Hi, > > running kernel 3.5.rc6 with the two gspca-sn9c20x webcams > > 0c45:62b3 Microdia PC Camera with Microphone (SN9C202 + OV9655) > 0c45:6270 Microdia PC Camera (SN9C201 + MI0360/MT9V011 or > MI0360SOC/MT9V111) U-CAM PC Camera NE878, Whitcom WHC017, ... > > I'm getting the following kernel oops when I start capturing with qv4l2 > (and also Kopete and others): > > [ 81.719973] gspca_sn9c20x: Set 640x480 > [ 81.736805] BUG: unable to handle kernel NULL pointer dereference at > 0000002c > [ 81.736877] IP: [] v4l2_ctrl_g_ctrl+0x9/0x50 [videodev] > [ 81.736901] *pdpt = 000000002c4fa001 *pde = 0000000000000000 > [ 81.736922] Oops: 0000 [#1] PREEMPT SMP > [ 81.737055] > [ 81.737071] Pid: 4026, comm: qv4l2 Not tainted 3.4.0-0.1-desktop+ #19 > System manufacturer System Product Name/M2N-VM DH > [ 81.737101] EIP: 0060:[] EFLAGS: 00010292 CPU: 1 > [ 81.737130] EIP is at v4l2_ctrl_g_ctrl+0x9/0x50 [videodev] > [ 81.737147] EAX: 00000000 EBX: 00000000 ECX: f6c000c0 EDX: 00000001 > [ 81.737165] ESI: 00000028 EDI: 00000028 EBP: f5af9c84 ESP: f5af9c7c > [ 81.737183] DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068 > [ 81.737200] CR0: 80050033 CR2: 0000002c CR3: 2c941000 CR4: 000007f0 > [ 81.737219] DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000 > [ 81.737236] DR6: ffff0ff0 DR7: 00000400 > [ 81.737252] Process qv4l2 (pid: 4026, ti=f5af8000 task=f594c030 > task.ti=f5af8000) > [ 81.737271] Stack: > [ 81.737290] 00000028 f61c2000 f5af9cd0 f7d1c74c 0000007f 00000000 > f5af9ca4 c0586ba1 > [ 81.737318] ef190444 0000007f 00000080 000001e0 00000280 00000002 > 00000000 02000100 > [ 81.737346] 003c2800 00f000a0 f61c2000 00000000 00000000 f5af9d84 > f7b682c0 f71d8bec > [ 81.737366] Call Trace: > [ 81.737390] [] sd_start+0x2dc/0x450 [gspca_sn9c20x] > [ 81.737421] [] ? usb_alloc_coherent+0x21/0x30 > [ 81.737448] [] gspca_init_transfer+0x260/0x420 [gspca_main] > [ 81.737479] [] ? __alloc_pages_nodemask+0x142/0x7b0 > [ 81.737504] [] vidioc_streamon+0x9b/0xb0 [gspca_main] > [ 81.737535] [] __video_do_ioctl+0x2ba9/0x5780 [videodev] > [ 81.737565] [] ? alloc_pages_current+0x8e/0x100 > [ 81.737588] [] ? kmap_atomic_prot+0xe8/0x110 > [ 81.737611] [] ? __copy_from_user_ll+0x1a/0x30 > [ 81.737630] [] ? _copy_from_user+0x30/0x50 > [ 81.737656] [] video_usercopy+0x1de/0x270 [videodev] > [ 81.737679] [] ? mmap_region+0x1e8/0x4b0 > [ 81.737706] [] video_ioctl2+0x12/0x20 [videodev] > [ 81.737725] [] ? v4l2_norm_to_name+0x50/0x50 [videodev] > [ 81.737725] [] v4l2_ioctl+0xca/0x190 [videodev] > [ 81.737725] [] ? do_mmap_pgoff+0x171/0x2e0 > [ 81.737725] [] ? v4l2_open+0x120/0x120 [videodev] > [ 81.737725] [] do_vfs_ioctl+0x74/0x2e0 > [ 81.737725] [] sys_ioctl+0x67/0x80 > [ 81.737725] [] syscall_call+0x7/0xb > [ 81.737725] Code: 55 f0 89 02 8b 46 10 8b 40 14 e8 03 61 c3 c8 89 f8 > 83 c4 04 5b 5e 5f 5d c3 89 f6 8d bc 27 00 00 00 00 55 89 e5 53 89 c3 83 > ec 04 <8b> 40 2c c7 45 f8 00 00 00 00 8d 50 fb 83 fa 02 77 09 80 b8 d3 > [ 81.737725] EIP: [] v4l2_ctrl_g_ctrl+0x9/0x50 [videodev] > SS:ESP 0068:f5af9c7c > [ 81.737725] CR2: 000000000000002c > [ 81.743027] ---[ end trace 1c291740d69b151f ]--- > > > This is a regression from kernel 3.4.x. > The causing commit seems to be > > > commit 63069da1c8ef0abcdb74b0ea1c461d23fb9181d9 > Author: Hans Verkuil > Date: Sun May 6 09:28:29 2012 -0300 > > [media] gcpca_sn9c20x: Convert to the control framework > > HdG: Small fix: don't register some controls for sensors which don't > have an implementation for them. > > Signed-off-by: Hans Verkuil > Signed-off-by: Hans de Goede > Signed-off-by: Mauro Carvalho Chehab > > > Should I open a bug report at bugzilla, too ? That won't be necessary, the attached patch should fix this, can you give it a try please? Thanks, Hans