From: Michal Wajdeczko <michal.wajdeczko@intel.com>
Date: Wed, 31 Jan 2018 17:32:39 +0000
Subject: drm/i915/guc: Don't try to create log runtime if there is no log
Git-commit: 28647b52ec0e20f84eb1b5e13095134e2b371759
Patch-mainline: v4.17-rc1
References: FATE#326289 FATE#326079 FATE#326049 FATE#322398 FATE#326166
In case of GuC initialization failure we may continue with driver
load, but we wrongly assume that GuC is fully functional. This
leads to the BUG as we attempt to access non-existing log vma.
[26386.121085] BUG: unable to handle kernel NULL pointer dereference at 00000000000000a0
[26386.121225] IP: guc_log_runtime_create+0x23/0xe0 [i915]
[26386.121763] Call Trace:
[26386.121870] guc_log_late_setup+0xfd/0x140 [i915]
[26386.121969] i915_driver_load+0x7ab/0x1730 [i915]
[26386.122069] i915_pci_probe+0x2d/0x90 [i915]
[26386.122089] pci_device_probe+0x9c/0x120
[26386.122107] driver_probe_device+0x2a9/0x490
[26386.122126] __driver_attach+0xd9/0xe0
[26386.122143] ? driver_probe_device+0x490/0x490
[26386.122158] bus_for_each_dev+0x57/0x90
[26386.122175] bus_add_driver+0x1eb/0x260
[26386.122190] ? 0xffffffffa069a000
[26386.122206] driver_register+0x52/0xc0
[26386.122220] ? 0xffffffffa069a000
[26386.122234] do_one_initcall+0x39/0x170
[26386.122252] ? kmem_cache_alloc_trace+0x1fd/0x2e0
[26386.122273] do_init_module+0x56/0x1ec
[26386.122289] load_module+0x219e/0x2550
[26386.122309] ? vfs_read+0x121/0x140
[26386.122331] ? SyS_finit_module+0xa5/0xe0
[26386.122346] SyS_finit_module+0xa5/0xe0
[26386.122371] entry_SYSCALL_64_fastpath+0x22/0x8f
Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Michal Winiarski <michal.winiarski@intel.com>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Sagar Arun Kamble <sagar.a.kamble@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180131173241.19704-4-michal.wajdeczko@intel.com
Reviewed-by: Sagar Arun Kamble <sagar.a.kamble@intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Acked-by: Petr Tesarik <ptesarik@suse.com>
---
drivers/gpu/drm/i915/intel_guc_log.c | 3 +++
1 file changed, 3 insertions(+)
--- a/drivers/gpu/drm/i915/intel_guc_log.c
+++ b/drivers/gpu/drm/i915/intel_guc_log.c
@@ -397,6 +397,9 @@ static int guc_log_runtime_create(struct
lockdep_assert_held(&dev_priv->drm.struct_mutex);
+ if (!guc->log.vma)
+ return -ENODEV;
+
GEM_BUG_ON(guc_log_has_runtime(guc));
ret = i915_gem_object_set_to_wc_domain(guc->log.vma->obj, true);