Am Montag, 5. März 2018, 09:57:40 CET schrieb Marek Szyprowski: > Enabling runtime power management early in analogix_dp_bind() causes > following kernel NULL pointer dereference: > > Unable to handle kernel NULL pointer dereference at virtual address 000007d8 > pgd = 28ffa2e4 > [000007d8] *pgd=00000000 > Internal error: Oops: 5 [#1] PREEMPT SMP ARM > Modules linked in: > CPU: 6 PID: 69 Comm: kworker/6:1 Not tainted 4.16.0-rc1-00062-ge25751974ba8 > #3622 Hardware name: SAMSUNG EXYNOS (Flattened Device Tree) > Workqueue: events deferred_probe_work_func > PC is at analogix_dp_resume+0x8/0xc0 > LR is at pm_generic_runtime_resume+0x2c/0x38 > pc : [<c0531b98>] lr : [<c0543fec>] psr: a0000113 > sp : ee13fbd8 ip : 0000001a fp : 00000001 > r10: ee0eb080 r9 : c0552bd8 r8 : c0fb1d98 > r7 : eebb1010 r6 : eeae9808 r5 : 00000000 r4 : d4850415 > r3 : ee0ed010 r2 : b2d05e00 r1 : 00000000 r0 : 00000000 > Flags: NzCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment none > Control: 10c5387d Table: 2000406a DAC: 00000051 > Process kworker/6:1 (pid: 69, stack limit = 0x913205b4) > Stack: (0xee13fbd8 to 0xee140000) > ... > [<c0531b98>] (analogix_dp_resume) from [<c0543fec>] > (pm_generic_runtime_resume+0x2c/0x38) [<c0543fec>] > (pm_generic_runtime_resume) from [<c054ffb4>] > (__genpd_runtime_resume+0x2c/0x8c) [<c054ffb4>] (__genpd_runtime_resume) > from [<c0552d24>] (genpd_runtime_resume+0x14c/0x258) [<c0552d24>] > (genpd_runtime_resume) from [<c0547798>] (__rpm_callback+0x134/0x214) > [<c0547798>] (__rpm_callback) from [<c0547898>] (rpm_callback+0x20/0x80) > [<c0547898>] (rpm_callback) from [<c0546ff4>] (rpm_resume+0x3a0/0x734) > [<c0546ff4>] (rpm_resume) from [<c05475ec>] (__pm_runtime_resume+0x64/0x9c) > [<c05475ec>] (__pm_runtime_resume) from [<c053b95c>] > (__device_attach+0x8c/0x134) [<c053b95c>] (__device_attach) from > [<c053ad08>] (bus_probe_device+0x88/0x90) [<c053ad08>] (bus_probe_device) > from [<c05390d0>] (device_add+0x3a8/0x580) [<c05390d0>] (device_add) from > [<c06764c4>] (i2c_register_adapter+0xd4/0x3ec) [<c06764c4>] > (i2c_register_adapter) from [<c05321c8>] (analogix_dp_bind+0x2a0/0x410) > [<c05321c8>] (analogix_dp_bind) from [<c0528e90>] > (exynos_dp_bind+0x9c/0x12c) [<c0528e90>] (exynos_dp_bind) from [<c0535bc4>] > (component_bind_all+0xfc/0x258) [<c0535bc4>] (component_bind_all) from > [<c0522ee8>] (exynos_drm_bind+0x15c/0x28c) [<c0522ee8>] (exynos_drm_bind) > from [<c0536378>] (try_to_bring_up_master+0x1b8/0x29c) [<c0536378>] > (try_to_bring_up_master) from [<c05364fc>] (component_add+0xa0/0x170) > [<c05364fc>] (component_add) from [<c0528fe4>] (exynos_dp_probe+0x64/0xb8) > [<c0528fe4>] (exynos_dp_probe) from [<c053debc>] > (platform_drv_probe+0x50/0xb0) [<c053debc>] (platform_drv_probe) from > [<c053bd18>] (driver_probe_device+0x2b8/0x4a0) [<c053bd18>] > (driver_probe_device) from [<c0539e4c>] (bus_for_each_drv+0x44/0x8c) > [<c0539e4c>] (bus_for_each_drv) from [<c053b970>] > (__device_attach+0xa0/0x134) [<c053b970>] (__device_attach) from > [<c053ad08>] (bus_probe_device+0x88/0x90) [<c053ad08>] (bus_probe_device) > from [<c053b258>] (deferred_probe_work_func+0x3c/0x168) [<c053b258>] > (deferred_probe_work_func) from [<c014352c>] (process_one_work+0x1d0/0x7bc) > [<c014352c>] (process_one_work) from [<c0143b84>] > (worker_thread+0x34/0x4dc) [<c0143b84>] (worker_thread) from [<c014a30c>] > (kthread+0x128/0x164) [<c014a30c>] (kthread) from [<c01010b4>] > (ret_from_fork+0x14/0x20) Exception stack(0xee13ffb0 to 0xee13fff8) > ffa0: 00000000 00000000 00000000 > 00000000 ffc0: 00000000 00000000 00000000 00000000 00000000 00000000 > 00000000 00000000 ffe0: 00000000 00000000 00000000 00000000 00000013 > 00000000 > Code: e2800e37 eafee601 e92d4070 e1a05000 (e59067d8) > ---[ end trace bf6046013df7cab2 ]--- > > This oops happens, because analogix_dp_bind() calls drm_dp_aux_register() > which registers i2c adapter. I2C core tries to runtime get i2c host > device during registration. This ends in analogix_dp_resume(), but dp > context is NULL there. dp context is set in exynos_dp_bind() after > executing analogix_dp_bind(). Fix this issue by postponing enabling runtime > power management after drm_dp_aux_register(). > > Signed-off-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx> on top of current drm-misc-next on rk3288 and rk3399 Tested-by: Heiko Stuebner <heiko@xxxxxxxxx> and the actual change also looks sane of course, so Reviewed-by: Heiko Stuebner <heiko@xxxxxxxxx> _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
