This patch fixes the following warning. The warning happens when using the Linux kernel 4.8-rc1 on kvm virtual machine, on Debian Jessie host. ================================================================================ UBSAN: Undefined behaviour in drivers/acpi/acpica/dsutils.c:641:16 index -1 is out of range for type 'acpi_operand_object *[9]' CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.8.0-rc1+ #2 Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 0000000000000000 ffff88011b17b9c8 ffffffff81264718 0000000000000002 ffff88011b17b9f0 ffffffffffffffff ffff88011b17b9e0 ffffffff8129397a ffffffff81add780 ffff88011b17ba30 ffffffff8129401e 0000000000000202 Call Trace: [<ffffffff81264718>] dump_stack+0x83/0xc1 [<ffffffff8129397a>] ubsan_epilogue+0xd/0x3a [<ffffffff8129401e>] __ubsan_handle_out_of_bounds+0x54/0x5d [<ffffffff812c8192>] acpi_ds_create_operand+0x249/0x2e4 [<ffffffff812c838d>] acpi_ds_create_operands+0x160/0x1b7 [<ffffffff812b34d3>] ? acpi_os_release_object+0x9/0xd [<ffffffff812eda68>] ? acpi_ut_delete_generic_state+0x18/0x1a [<ffffffff812e2b94>] ? acpi_ps_pop_scope+0xde/0x13c [<ffffffff812c8c71>] acpi_ds_exec_end_op+0x335/0x57d [<ffffffff812e1670>] acpi_ps_parse_loop+0x729/0x78b [<ffffffff812ed97b>] ? acpi_ut_create_generic_state+0x34/0x3f [<ffffffff812e270c>] acpi_ps_parse_aml+0xa7/0x2d6 [<ffffffff812e32fb>] acpi_ps_execute_method+0x1f3/0x231 [<ffffffff812db33f>] acpi_ns_evaluate+0x22e/0x2be [<ffffffff812df1e5>] acpi_evaluate_object+0x13c/0x255 [<ffffffff8117c8e6>] ? kfree+0x1b2/0x1c1 [<ffffffff812bb50b>] acpi_get_phys_id+0x38/0x11a [<ffffffff812bb75f>] acpi_get_cpuid+0xc/0x18 [<ffffffff81c86f23>] early_init_pdc+0x8d/0xa2 [<ffffffff812defac>] acpi_ns_walk_namespace+0x11c/0x1ea [<ffffffff81c86e96>] ? set_no_mwait+0x3b/0x3b [<ffffffff81c86e96>] ? set_no_mwait+0x3b/0x3b [<ffffffff812df40d>] acpi_walk_namespace+0x9b/0xd0 [<ffffffff81c863b4>] ? acpi_sleep_init+0x120/0x120 [<ffffffff81c86f68>] acpi_early_processor_set_pdc+0x30/0x4a [<ffffffff81c86535>] acpi_init+0x181/0x2e5 [<ffffffff81c863b4>] ? acpi_sleep_init+0x120/0x120 [<ffffffff810004aa>] do_one_initcall+0xd3/0x164 [<ffffffff81c5c522>] kernel_init_freeable+0x246/0x2d8 [<ffffffff81420713>] kernel_init+0xa/0x103 [<ffffffff8142ed0f>] ret_from_fork+0x1f/0x40 [<ffffffff81420709>] ? rest_init+0x160/0x160 ================================================================================ Signed-off-by: Mikulas Patocka <mpatocka@xxxxxxxxxx> Index: linux-2.6/drivers/acpi/acpica/dsutils.c =================================================================== --- linux-2.6.orig/drivers/acpi/acpica/dsutils.c +++ linux-2.6/drivers/acpi/acpica/dsutils.c @@ -637,11 +637,10 @@ acpi_ds_create_operand(struct acpi_walk_ ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH, "Argument previously created, already stacked\n")); - acpi_db_display_argument_object(walk_state-> - operands[walk_state-> - num_operands - - 1], - walk_state); + if (walk_state->num_operands) + acpi_db_display_argument_object(walk_state-> + operands[walk_state-> num_operands - 1], + walk_state); /* * Use value that was already previously returned -- 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
