On Fri, Jul 12, 2019 at 12:07:46PM -0400, Tony Camuso wrote: > On 7/10/19 9:56 AM, Ville Syrjälä wrote: > > On Wed, Jul 10, 2019 at 09:47:11AM -0400, Tony Camuso wrote: > >> On 5/24/19 4:36 AM, Jani Nikula wrote: > >>> On Thu, 23 May 2019, tcamuso <tcamuso@xxxxxxxxxx> wrote: > >>>> From Daniel Kwon <dkwon@xxxxxxxxxx> > >>>> > >>>> The system was crashed due to invalid memory access while trying to access > >>>> auxiliary device. > >>>> > >>>> crash> bt > >>>> PID: 9863 TASK: ffff89d1bdf11040 CPU: 1 COMMAND: "ipmitool" > >>>> #0 [ffff89cedd7f3868] machine_kexec at ffffffffb0663674 > >>>> #1 [ffff89cedd7f38c8] __crash_kexec at ffffffffb071cf62 > >>>> #2 [ffff89cedd7f3998] crash_kexec at ffffffffb071d050 > >>>> #3 [ffff89cedd7f39b0] oops_end at ffffffffb0d6d758 > >>>> #4 [ffff89cedd7f39d8] no_context at ffffffffb0d5bcde > >>>> #5 [ffff89cedd7f3a28] __bad_area_nosemaphore at ffffffffb0d5bd75 > >>>> #6 [ffff89cedd7f3a78] bad_area at ffffffffb0d5c085 > >>>> #7 [ffff89cedd7f3aa0] __do_page_fault at ffffffffb0d7080c > >>>> #8 [ffff89cedd7f3b10] do_page_fault at ffffffffb0d70905 > >>>> #9 [ffff89cedd7f3b40] page_fault at ffffffffb0d6c758 > >>>> [exception RIP: drm_dp_aux_dev_get_by_minor+0x3d] > >>>> RIP: ffffffffc0a589bd RSP: ffff89cedd7f3bf0 RFLAGS: 00010246 > >>>> RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffff89cedd7f3fd8 > >>>> RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffffc0a613e0 > >>>> RBP: ffff89cedd7f3bf8 R8: ffff89f1bcbabbd0 R9: 0000000000000000 > >>>> R10: ffff89f1be7a1cc0 R11: 0000000000000000 R12: 0000000000000000 > >>>> R13: ffff89f1b32a2830 R14: ffff89d18fadfa00 R15: 0000000000000000 > >>>> ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018 > >>>> RIP: 00002b45f0d80d30 RSP: 00007ffc416066a0 RFLAGS: 00010246 > >>>> RAX: 0000000000000002 RBX: 000056062e212d80 RCX: 00007ffc41606810 > >>>> RDX: 0000000000000000 RSI: 0000000000000002 RDI: 00007ffc41606ec0 > >>>> RBP: 0000000000000000 R8: 000056062dfed229 R9: 00002b45f0cdf14d > >>>> R10: 0000000000000002 R11: 0000000000000246 R12: 00007ffc41606ec0 > >>>> R13: 00007ffc41606ed0 R14: 00007ffc41606ee0 R15: 0000000000000000 > >>>> ORIG_RAX: 0000000000000002 CS: 0033 SS: 002b > >>>> > >>>> ---------------------------------------------------------------------------- > >>>> > >>>> It was trying to open '/dev/ipmi0', but as no entry in aux_dir, it returned > >>>> NULL from 'idr_find()'. This drm_dp_aux_dev_get_by_minor() should have done a > >>>> check on this, but had failed to do it. > >>> > >>> I think the better question is, *why* does the idr_find() return NULL? I > >>> don't think it should, under any circumstances. I fear adding the check > >>> here papers over some other problem, taking us further away from the > >>> root cause. > >>> > >>> Also, can you reproduce this on a recent upstream kernel? The aux device > >>> nodes were introduced in kernel v4.6. Whatever you reproduced on v3.10 > >>> is pretty much irrelevant for upstream. > >>> > >>> > >>> BR, > >>> Jani. > >> > >> I have not been able to reproduce this problem. > > > > mknod /dev/foo c <drm_dp_aux major> 255 > > cat /dev/foo > > > > should do it. > > How do I determine <drm_dp_aux major>? ls,file,stat. Take your pick. -- Ville Syrjälä Intel _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
