Quoting Michal Wajdeczko (2018-01-31 17:32:39) > 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@xxxxxxxxx> > Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> > Cc: Michal Winiarski <michal.winiarski@xxxxxxxxx> > Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@xxxxxxxxx> > Cc: Sagar Arun Kamble <sagar.a.kamble@xxxxxxxxx> > --- > drivers/gpu/drm/i915/intel_guc_log.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/drivers/gpu/drm/i915/intel_guc_log.c b/drivers/gpu/drm/i915/intel_guc_log.c > index 3fbe93a..fdb1895 100644 > --- a/drivers/gpu/drm/i915/intel_guc_log.c > +++ b/drivers/gpu/drm/i915/intel_guc_log.c > @@ -395,6 +395,9 @@ static int guc_log_runtime_create(struct intel_guc *guc) > void *vaddr; > int ret; > > + if (!guc->log.vma) > + return -ENODEV; > + > lockdep_assert_held(&dev_priv->drm.struct_mutex); We like to keep the caller precondition guards at the start of the function, so I reversed this pair of lines. I've pushed the two BUG fixes that Sagar reviewed. The fault injection is a good idea, but I've left it alone while there is a question on a couple of the patches. Thanks for the patches and review, looking forward to the next series :) -Chris _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
