Hi Hans,
We have found this crash in mainline:
[ 258.174662] Unable to handle kernel NULL pointer dereference at
virtual address 0000000000000000
[ 258.182967] Mem abort info:
[ 258.187746] ESR = 0x96000004
[ 258.192100] EC = 0x25: DABT (current EL), IL = 32 bits
[ 258.199108] SET = 0, FnV = 0
[ 258.203732] EA = 0, S1PTW = 0
[ 258.208389] Data abort info:
[ 258.212743] ISV = 0, ISS = 0x00000004
[ 258.218322] CM = 0, WnR = 0
[ 258.222760] user pgtable: 4k pages, 48-bit VAs, pgdp=00000000444b0000
[ 258.230822] [0000000000000000] pgd=0000000000000000, p4d=0000000000000000
[ 258.239097] Internal error: Oops: 96000004 [#1] PREEMPT SMP
[ 258.246162] Modules linked in: hantro_vpu(C) videobuf2_vmalloc
v4l2_h264 videobuf2_dma_contig videobuf2_memops v4l2_mem2mem
videobuf2_v4l2 videobuf2_common videodev mc etnaviv fsl_imx8_ddr_perf
gpu_sched fuse
[ 258.263431] CPU: 0 PID: 34 Comm: kworker/0:1 Tainted: G C
5.12.0-rc2+ #106
[ 258.270312] Hardware name: NXP i.MX8MQ EVK (DT)
[ 258.273542] Workqueue: events v4l2_m2m_device_run_work [v4l2_mem2mem]
[ 258.278716] pstate: 80000005 (Nzcv daif -PAN -UAO -TCO BTYPE=--)
[ 258.283426] pc : __memcpy+0x7c/0x180
[ 258.285709] lr : v4l2_ctrl_request_complete+0x7c/0x200 [videodev]
[ 258.290585] sp : ffff8000116fbc60
[ 258.292598] x29: ffff8000116fbc60 x28: ffff80001142b780
[ 258.296617] x27: ffff80001127bc80 x26: 00000000e9b00000
[ 258.300637] x25: 00000000e9a00000 x24: ffff0000067e2500
[ 258.304653] x23: ffff0000067e2538 x22: ffff00000387d238
[ 258.308671] x21: ffff0000067e2598 x20: ffff000004644e00
[ 258.312688] x19: ffff000006812a00 x18: 0000000000000000
[ 258.316708] x17: 0000000000000000 x16: 0000000000000000
[ 258.320724] x15: 0000000000000000 x14: 0000000000000000
[ 258.324744] x13: 0000000000000000 x12: 0000000000000000
[ 258.328761] x11: 0000000000000000 x10: 0000000000000000
[ 258.332776] x9 : 0000000000000000 x8 : 0000000000000000
[ 258.336793] x7 : 0000000000000000 x6 : ffff000006812a40
[ 258.340811] x5 : 0000000000000006 x4 : 0000000000000000
[ 258.344826] x3 : 0000000000000010 x2 : 0000000000000010
[ 258.348845] x1 : 0000000000000000 x0 : ffff000006812a40
[ 258.352864] Call trace:
[ 258.354010] __memcpy+0x7c/0x180
[ 258.355941] hantro_end_prepare_run+0x2c/0x60 [hantro_vpu]
[ 258.360150] hantro_g1_mpeg2_dec_run+0x3b0/0x7f0 [hantro_vpu]
[ 258.364615] device_run+0xa8/0xbc [hantro_vpu]
[ 258.367777] v4l2_m2m_try_run+0x84/0x134 [v4l2_mem2mem]
[ 258.371723] v4l2_m2m_device_run_work+0x14/0x20 [v4l2_mem2mem]
[ 258.376279] process_one_work+0x1c0/0x484
[ 258.378995] worker_thread+0x70/0x434
[ 258.381364] kthread+0x158/0x160
[ 258.383296] ret_from_fork+0x10/0x34
[ 258.385582] Code: a8c12027 a88120c7 a8c12027 a88120c7 (a8c12027)
[ 258.390377] ---[ end trace fea6ecb96dad642d ]---
This needs several concurrent streams to run at the same time,
it doesn't happen with just one; it was reproduced in rkvdec
and hantro drivers. The above stacktrace is on MPEG-2,
but we have found it on H.264 as well.
I've traced this to:
v4l2_ctrl_lock(ctrl);
if (ref->req) {
ptr_to_ptr(ctrl, ref->req->p_req, ref->p_req);
And:
static void ptr_to_ptr(struct v4l2_ctrl *ctrl,
union v4l2_ctrl_ptr from, union v4l2_ctrl_ptr to)
{
if (ctrl == NULL)
return;
memcpy(to.p, from.p_const, ctrl->elems * ctrl->elem_size);
^^^^^^^^^^^^
This is NULL
I've been staring at this file and trying to understand how this can happen
but haven't been able to make any progress so far...
Any ideas ?
Thanks,
Ezequiel
