On Wed, 13 Nov 2024, Jani Nikula <jani.nikula@xxxxxxxxxxxxxxx> wrote: > On Wed, 13 Nov 2024, Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx> wrote: >> On (24/10/31 19:51), Sergey Senozhatsky wrote: >>> intel_ddi_init() may skip connector initialization, for instance, >>> both intel_ddi_init_dp_connector() and intel_ddi_init_hdmi_connector() >>> are optional. This leads to situation that ->attached_connector may >>> be NULL for some connectors. For instance, on my setup 'DDI A/PHY A' >>> and 'DDI TC1/PHY TC1' are not initialized. >>> >>> However, functions like intel_dp_dual_mode_set_tmds_output() and >>> friends don't take this into consideration. This leads to NULL >>> ptr-derefs: >>> >>> KASAN: null-ptr-deref in range [0x0000000000000848-0x000000000000084f] >>> RIP: 0010:intel_hdmi_encoder_shutdown+0x105/0x230 >>> Call Trace: >>> <TASK> >>> i915_driver_shutdown+0x2d8/0x490 >>> pci_device_shutdown+0x83/0x150 >>> device_shutdown+0x4ad/0x660 >>> __se_sys_reboot+0x29c/0x4d0 >>> do_syscall_64+0x60/0x90 >>> >>> Add a new helper to avoid NULL ->attached_connector derefs and >>> switch some intel_hdmi function to it. I'm not sure if we need >>> to switch all or just intel_dp_dual_mode_set_tmds_output() (I >>> have only seen this one doing NULL derefs so far). >> >> Folks, any more comments / opinions on this? >> What should be the way forward? > > Ville, we handle intel_ddi_init_dp_connector() failures but not > intel_ddi_init_hdmi_connector() failures. Do you recall if there's a > reason for that? Something like a dual-mode port where DP works but HDMI > gets rejected because of bogus VBT info? > > My gut feeling is to propagate errors from intel_hdmi_init_connector() > and handle them properly in g4x_hdmi_init() and > intel_ddi_init_hdmi_connector(). > > Of course, we have cases where hdmi is just not initialized on DDI, and > those should be handled. But I don't think hdmi->attached_connector != > NULL is really the right check for that. I'm hoping [1] would solve the issue. BR, Jani. [1] https://lore.kernel.org/r/cover.1731599468.git.jani.nikula@xxxxxxxxx -- Jani Nikula, Intel
