On Fri, May 24, 2019 at 06:48:32AM -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. > > That's a very good question. > > > 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. > > I will look into this deeper, using the upstream kernel. Should be trivial to reproduce with mknod. I wonder if we should stick a test like that into igt actually. Not sure how happy people would be if igt creates new device nodes... -- Ville Syrjälä Intel _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
