component_unbind_all() splat..

[Rob Clark]

Hey Russell,

I just noticed a splat triggered by component_unbind_all() called from
->bind()..  any opinions about whether component stuff should handle
that case, or whether I should rearrange my error cleanup path to not
component_unbind_all() in this case?

[    2.329829] msm 1a00000.qcom,mdss_mdp: failed to allocate VRAM
[    2.334027] ------------[ cut here ]------------
[    2.339754] WARNING: CPU: 1 PID: 1 at
../drivers/base/component.c:356 component_unbind.isra.2+0x5c/0x68()
[    2.344536] Modules linked in:
[    2.356918] CPU: 1 PID: 1 Comm: swapper/0 Not tainted 4.0.0-dirty #5
[    2.356996] Hardware name: Qualcomm Technologies, Inc. APQ 8016 SBC (DT)
[    2.363420] Call trace:
[    2.370110] [<ffffffc000089c78>] dump_backtrace+0x0/0x118
[    2.372276] [<ffffffc000089da0>] show_stack+0x10/0x20
[    2.377840] [<ffffffc0006686bc>] dump_stack+0x84/0xc4
[    2.382865] [<ffffffc0000b1afc>] warn_slowpath_common+0x94/0xd0
[    2.387910] [<ffffffc0000b1bdc>] warn_slowpath_null+0x14/0x20
[    2.393631] [<ffffffc00042a450>] component_unbind.isra.2+0x58/0x68
[    2.399543] [<ffffffc00042a4e4>] component_unbind_all+0x84/0xc0
[    2.405619] [<ffffffc000419c70>] msm_unload+0x118/0x1a0
[    2.411425] [<ffffffc00041a2f8>] msm_load+0xe0/0x3b8
[    2.416643] [<ffffffc0003e6a00>] drm_dev_register+0xb8/0x110
[    2.421843] [<ffffffc0003e8c5c>] drm_platform_init+0x44/0xe0
[    2.427493] [<ffffffc000419490>] msm_drm_bind+0x18/0x28
[    2.433125] [<ffffffc00042a160>] try_to_bring_up_master.part.1+0xc0/0x108
[    2.438087] [<ffffffc00042a258>] component_master_add_with_match+0xb0/0x138
[    2.445031] [<ffffffc000419eb4>] msm_pdev_probe+0x64/0x78
[    2.451791] [<ffffffc000430c68>] platform_drv_probe+0x48/0xb8
[    2.457355] [<ffffffc00042f0ec>] driver_probe_device+0x8c/0x248
[    2.463074] [<ffffffc00042f398>] __driver_attach+0x98/0xa0
[    2.468811] [<ffffffc00042d52c>] bus_for_each_dev+0x5c/0xa0
[    2.474366] [<ffffffc00042ec04>] driver_attach+0x1c/0x28
[    2.479826] [<ffffffc00042e864>] bus_add_driver+0x14c/0x208
[    2.485390] [<ffffffc00042fa2c>] driver_register+0x5c/0x120
[    2.490679] [<ffffffc000430b98>] __platform_driver_register+0x58/0x68
[    2.496246] [<ffffffc000a4b268>] msm_drm_register+0x48/0x54
[    2.502831] [<ffffffc0000828e0>] do_one_initcall+0x88/0x1a8
[    2.508223] [<ffffffc000a2dac4>] kernel_init_freeable+0x144/0x1ec
[    2.513769] [<ffffffc0006663ac>] kernel_init+0xc/0xe0
[    2.520034] ---[ end trace 7e1590a270796f2f ]---
[    2.525063] Unable to handle kernel NULL pointer dereference at
virtual address 00000028