Plugging in a USB-C power source on my Dell XPS 9550 trips an ACPI BUG_ON [1], reproducible with mainline 4.14.44, suggesting other threads are waiting for semaphore acquisition due to "BUG_ON(!list_empty(&sem->wait_list))". This is the current 1.7.0 BIOS with Ubuntu 18.04 userspace, plugging in an LG 27UD88 (also with the current firmware) monitor USB-C connection which apparently advertises 60W charging (x1, PowerDelivery, DisplayPort alternative mode, data). The same issues reproduce on a Dell Precision 5510 with Ubuntu 16.04, the shipped kernel and 4.14.44. I can enable ACPI debugging if useful? Perhaps ACPI_DB_MUTEX or other levels would be appropriate? Thanks, Daniel -- [1] kernel BUG at /home/kernel/COD/linux/drivers/acpi/osl.c:1201 invalid opcode: 0000 [#1] SMP PTI Modules linked in: [...] CPU: 0 PID: 1 Comm: systemd-shutdow Not tainted 4.14.44-041444-generic #201805251612 Hardware name: Dell Inc. XPS 15 9550/, BIOS 1.7.0 02/23/2018 task: ffff9bc2ab6b9740 task.stack: ffffbOca80034000 RIP: 0010:acpi_os_delete_semaphore+0x6d/0x70 RSP: 0018:ffffbOca80037be8 EFLAGS: 00010283 RAX: ffffbOca83f8fc40 RBX: ffff9bc238b5dbe0 RCX: 0000000000000000 RDX: ffff9bc238b5dbe8 RSI: 0000000000000000 RDI: ffff9bc238b5dbe0 RBP: ffff9bc2adlc0990 ROB: ffff9bc2bdc25f20 R09: ffff9bc29ee56300 R10: ffffe03bd2796440 R11: ffff9bc2ad183fa0 R12: ffff9bc22f1321e0 R13: 0000000000000001 R14: 0000000000000001 R15: ffff9bc22f132eb0 FS: 00007fc03886f940(0000) GS:ffff9bc2bdc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CRO: 0000000080050033 CR2: 00007ffc645e70f8 CR3: 000000049e120001 CR4: 00000000003606f0 Call Trace: acpi_ex_system_reset_event+0x3f/0x65 acpi_ex_opcode_1A_OT_0R+0x70/0xfa acpi_ds_exec_end_op+0x15d/0x71b acpi_ps_parse_loop+0x929/0x9d6 ? acpi_ds_result_push+0x82/0x1d2 acpi_ps_parse_aml+0x1a2/0x4af acpi_ps_execute_method+0x1ef/0x2ab acpi_ns_evaluate+0x2e4/0x41d acpi_evaluate_object+0x1cb/0x38e acpi_enter_sleep_state_prep+0xae/0x13a acpi_sleep_prepare.part.2+0x2e/0x40 acpi_power_off_prepare+0xf/0x20 [38871.1925361 kernel_power_off+0x42/0x70 SYSC_reboot+0x12f/0x210 ? handle_mm_fault+0xea/0x1e0 [38871.1925861 ? do_writev+0x5e/0xf0 ? do_writev+0x5e/0xf0 do_syscall_64+0x6e/0x120 entry_SYSCALL_64_after_hwframe+0x3d/0xa2 RIP: 0033:0x7fc03839b373 RSP: 002b:00007ffc645e70f8 EFLAGS: 00000202 ORIG_RAX: 00000000000000a9 RAX: ffffffffffffffda RBX: 000000004321fedc RCX: 00007fc03839b373 ROX: 000000004321fedc RSI: 0000000028121969 RDI: 00000000fee1dead RBP: 00007ffc645e7160 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000002 R11: 0000000000000202 R12: 00007ffc645e7168 R13: 0000000000000000 R14: 0000001b00000004 R15: 00007ffc645e7458 Code: b8 00 04 00 00 48 c7 c1 c3 91 28 ab 48 c7 c2 20 91 28 ab be of 04 00 00 bf 00 00 00 01 03 41 85 04 00 58 eb b0 b8 01 10 00 00 c3 <Of> Ob 90 Of if 44 00 00 80 3d 74 CO 97 01 00 41 54 55 53 Of 84 RIP: acpi_os_delete_semaphore+0x6d/0x70 RSP: ffffb0ca80037be8 -- Daniel J Blueman -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
