On Fri, 10 Sept 2021 at 16:32, Jia He <justin.he@xxxxxxx> wrote: > > This reverts commit 437b38c51162f8b87beb28a833c4d5dc85fa864e. > > After this commit, a boot panic is alway hit on an Ampere EMAG server > with call trace as follows: > Internal error: synchronous external abort: 96000410 [#1] SMP > Modules linked in: > CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.14.0+ #462 > Hardware name: MiTAC RAPTOR EV-883832-X3-0001/RAPTOR, BIOS 0.14 02/22/2019 > pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--) > [...snip...] > Call trace: > acpi_ex_system_memory_space_handler+0x26c/0x2c8 > acpi_ev_address_space_dispatch+0x228/0x2c4 > acpi_ex_access_region+0x114/0x268 > acpi_ex_field_datum_io+0x128/0x1b8 > acpi_ex_extract_from_field+0x14c/0x2ac > acpi_ex_read_data_from_field+0x190/0x1b8 > acpi_ex_resolve_node_to_value+0x1ec/0x288 > acpi_ex_resolve_to_value+0x250/0x274 > acpi_ds_evaluate_name_path+0xac/0x124 > acpi_ds_exec_end_op+0x90/0x410 > acpi_ps_parse_loop+0x4ac/0x5d8 > acpi_ps_parse_aml+0xe0/0x2c8 > acpi_ps_execute_method+0x19c/0x1ac > acpi_ns_evaluate+0x1f8/0x26c > acpi_ns_init_one_device+0x104/0x140 > acpi_ns_walk_namespace+0x158/0x1d0 > acpi_ns_initialize_devices+0x194/0x218 > acpi_initialize_objects+0x48/0x50 > acpi_init+0xe0/0x498 > > As mentioned by Lorenzo: > "We are forcing memory semantics mappings to PROT_NORMAL_NC, which > eMAG does not like at all and I'd need to understand why. It looks > like the issue happen in SystemMemory Opregion handler." > > Hence just revert it before everything is clear. > Can we try to find the root cause first? -rc1 is not even out yet, and reverting it now means we can not resubmit it until the next merge window.
