On Wed, Feb 12, 2020 at 02:54:45PM +0100, Maarten Lankhorst wrote:
> This fixes the following KASAN splash on module reload:
> [ 145.136327] ==================================================================
> [ 145.136502] BUG: KASAN: use-after-free in intel_hdmi_destroy+0x74/0x80 [i915]
> [ 145.136514] Read of size 8 at addr ffff888216641830 by task kworker/1:1/134
>
> [ 145.136535] CPU: 1 PID: 134 Comm: kworker/1:1 Tainted: G U T 5.5.0-rc7-valkyria+ #5783
> [ 145.136539] Hardware name: GIGABYTE GB-BKi3A-7100/MFLP3AP-00, BIOS F1 07/27/2016
> [ 145.136546] Workqueue: events drm_connector_free_work_fn
> [ 145.136551] Call Trace:
> [ 145.136560] dump_stack+0xa1/0xe0
> [ 145.136571] print_address_description.constprop.0+0x1e/0x210
> [ 145.136639] ? intel_hdmi_destroy+0x74/0x80 [i915]
> [ 145.136703] ? intel_hdmi_destroy+0x74/0x80 [i915]
> [ 145.136710] __kasan_report.cold+0x1b/0x37
> [ 145.136790] ? intel_hdmi_destroy+0x74/0x80 [i915]
> [ 145.136863] ? intel_hdmi_destroy+0x74/0x80 [i915]
> [ 145.136870] kasan_report+0x27/0x30
> [ 145.136881] __asan_report_load8_noabort+0x1c/0x20
> [ 145.136946] intel_hdmi_destroy+0x74/0x80 [i915]
> [ 145.136954] drm_connector_free_work_fn+0xd1/0x100
> [ 145.136967] process_one_work+0x86e/0x1610
> [ 145.136987] ? pwq_dec_nr_in_flight+0x2f0/0x2f0
> [ 145.137004] ? move_linked_works+0x128/0x2c0
> [ 145.137021] worker_thread+0x63e/0xc90
> [ 145.137048] kthread+0x2f6/0x3f0
> [ 145.137054] ? calculate_sigpending+0x81/0xa0
> [ 145.137059] ? process_one_work+0x1610/0x1610
> [ 145.137064] ? kthread_bind+0x40/0x40
> [ 145.137075] ret_from_fork+0x24/0x30
>
> [ 145.137111] Allocated by task 0:
> [ 145.137119] (stack is not available)
>
> [ 145.137137] Freed by task 5053:
> [ 145.137147] save_stack+0x28/0x90
> [ 145.137152] __kasan_slab_free+0x136/0x180
> [ 145.137157] kasan_slab_free+0x26/0x30
> [ 145.137161] kfree+0xe6/0x350
> [ 145.137242] intel_ddi_encoder_destroy+0x60/0x80 [i915]
> [ 145.137252] drm_mode_config_cleanup+0x11d/0x8f0
> [ 145.137329] intel_modeset_driver_remove+0x1f5/0x350 [i915]
> [ 145.137403] i915_driver_remove+0xc4/0x130 [i915]
> [ 145.137482] i915_pci_remove+0x3e/0x90 [i915]
> [ 145.137489] pci_device_remove+0x108/0x2d0
> [ 145.137494] device_release_driver_internal+0x1e6/0x4a0
> [ 145.137499] driver_detach+0xcb/0x198
> [ 145.137503] bus_remove_driver+0xde/0x204
> [ 145.137508] driver_unregister+0x6d/0xa0
> [ 145.137513] pci_unregister_driver+0x2e/0x230
> [ 145.137576] i915_exit+0x1f/0x26 [i915]
> [ 145.137157] kasan_slab_free+0x26/0x30
> [ 145.137161] kfree+0xe6/0x350
> [ 145.137242] intel_ddi_encoder_destroy+0x60/0x80 [i915]
> [ 145.137252] drm_mode_config_cleanup+0x11d/0x8f0
> [ 145.137329] intel_modeset_driver_remove+0x1f5/0x350 [i915]
> [ 145.137403] i915_driver_remove+0xc4/0x130 [i915]
> [ 145.137482] i915_pci_remove+0x3e/0x90 [i915]
> [ 145.137489] pci_device_remove+0x108/0x2d0
> [ 145.137494] device_release_driver_internal+0x1e6/0x4a0
> [ 145.137499] driver_detach+0xcb/0x198
> [ 145.137503] bus_remove_driver+0xde/0x204
> [ 145.137508] driver_unregister+0x6d/0xa0
> [ 145.137513] pci_unregister_driver+0x2e/0x230
> [ 145.137576] i915_exit+0x1f/0x26 [i915]
> [ 145.137581] __x64_sys_delete_module+0x35b/0x470
> [ 145.137586] do_syscall_64+0x99/0x4e0
> [ 145.137591] entry_SYSCALL_64_after_hwframe+0x49/0xbe
>
> [ 145.137606] The buggy address belongs to the object at ffff888216640000
> which belongs to the cache kmalloc-8k of size 8192
> [ 145.137618] The buggy address is located 6192 bytes inside of
> 8192-byte region [ffff888216640000, ffff888216642000)
> [ 145.137630] The buggy address belongs to the page:
> [ 145.137640] page:ffffea0008599000 refcount:1 mapcount:0 mapping:ffff888107c02a80 index:0xffff888216644000 compound_mapcount: 0
> [ 145.137647] raw: 0200000000010200 0000000000000000 0000000100000001 ffff888107c02a80
> [ 145.137652] raw: ffff888216644000 0000000080020001 00000001ffffffff 0000000000000000
> [ 145.137656] page dumped because: kasan: bad access detected
>
> [ 145.137668] Memory state around the buggy address:
> [ 145.137678] ffff888216641700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> [ 145.137687] ffff888216641780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> [ 145.137697] >ffff888216641800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> [ 145.137706] ^
> [ 145.137715] ffff888216641880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> [ 145.137724] ffff888216641900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> [ 145.137733] ==================================================================
> [ 145.137742] Disabling lock debugging due to kernel taint
>
> Changes since v1:
> - Add fixes tags.
> - Use early unregister.
Yeah, much better than v1.
Reviewed-by: Daniel Vetter <daniel.vetter@xxxxxxxx>
>
> Signed-off-by: Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxxxx>
> Fixes: 9c229127aee2 ("drm/i915: hdmi: add CEC notifier to intel_hdmi")
> Cc: <stable@xxxxxxxxxxxxxxx> # v4.19+
> ---
> drivers/gpu/drm/i915/display/intel_hdmi.c | 10 ++--------
> 1 file changed, 2 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_hdmi.c b/drivers/gpu/drm/i915/display/intel_hdmi.c
> index e68bafb76cb1..34ee75fdaaf9 100644
> --- a/drivers/gpu/drm/i915/display/intel_hdmi.c
> +++ b/drivers/gpu/drm/i915/display/intel_hdmi.c
> @@ -2830,19 +2830,13 @@ intel_hdmi_connector_register(struct drm_connector *connector)
> return ret;
> }
>
> -static void intel_hdmi_destroy(struct drm_connector *connector)
> +static void intel_hdmi_connector_unregister(struct drm_connector *connector)
> {
> struct cec_notifier *n = intel_attached_hdmi(to_intel_connector(connector))->cec_notifier;
>
> cec_notifier_conn_unregister(n);
>
> - intel_connector_destroy(connector);
> -}
> -
> -static void intel_hdmi_connector_unregister(struct drm_connector *connector)
> -{
> intel_hdmi_remove_i2c_symlink(connector);
> -
> intel_connector_unregister(connector);
> }
>
> @@ -2854,7 +2848,7 @@ static const struct drm_connector_funcs intel_hdmi_connector_funcs = {
> .atomic_set_property = intel_digital_connector_atomic_set_property,
> .late_register = intel_hdmi_connector_register,
> .early_unregister = intel_hdmi_connector_unregister,
> - .destroy = intel_hdmi_destroy,
> + .destroy = intel_connector_destroy,
> .atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
> .atomic_duplicate_state = intel_digital_connector_duplicate_state,
> };
> --
> 2.25.0.24.g3f081b084b0
>
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--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
