5.10-stable review patch. If anyone has any objections, please let me know.
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From: Alvin Šipraga alsi@bang-olufsen.dk
[ Upstream commit 40cdb02cb9f965732eb543d47f15bef8d10f0f5f ]
cec_unregister_adapter() assumes that the underlying adapter ops are callable. For example, if the CEC adapter currently has a valid physical address, then the unregistration procedure will invalidate the physical address by setting it to f.f.f.f. Whence the following kernel oops observed after removing the adv7511 module:
Unable to handle kernel execution of user memory at virtual address 0000000000000000 Internal error: Oops: 86000004 [#1] PREEMPT_RT SMP Call trace: 0x0 adv7511_cec_adap_log_addr+0x1ac/0x1c8 [adv7511] cec_adap_unconfigure+0x44/0x90 [cec] __cec_s_phys_addr.part.0+0x68/0x230 [cec] __cec_s_phys_addr+0x40/0x50 [cec] cec_unregister_adapter+0xb4/0x118 [cec] adv7511_remove+0x60/0x90 [adv7511] i2c_device_remove+0x34/0xe0 device_release_driver_internal+0x114/0x1f0 driver_detach+0x54/0xe0 bus_remove_driver+0x60/0xd8 driver_unregister+0x34/0x60 i2c_del_driver+0x2c/0x68 adv7511_exit+0x1c/0x67c [adv7511] __arm64_sys_delete_module+0x154/0x288 invoke_syscall+0x48/0x100 el0_svc_common.constprop.0+0x48/0xe8 do_el0_svc+0x28/0x88 el0_svc+0x1c/0x50 el0t_64_sync_handler+0xa8/0xb0 el0t_64_sync+0x15c/0x160 Code: bad PC value ---[ end trace 0000000000000000 ]---
Protect against this scenario by unregistering i2c_cec after unregistering the CEC adapter. Duly disable the CEC clock afterwards too.
Fixes: 3b1b975003e4 ("drm: adv7511/33: add HDMI CEC support") Signed-off-by: Alvin Šipraga alsi@bang-olufsen.dk Reviewed-by: Robert Foss robert.foss@linaro.org Signed-off-by: Robert Foss robert.foss@linaro.org Link: https://patchwork.freedesktop.org/patch/msgid/20220612144854.2223873-3-alvin... Stable-dep-of: 81adbd3ff21c ("drm: adv7511: Fix use-after-free in adv7533_attach_dsi()") Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/gpu/drm/bridge/adv7511/adv7511_drv.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c index 42d93f314699..9e8f45fa5c5e 100644 --- a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c +++ b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c @@ -1339,9 +1339,6 @@ static int adv7511_remove(struct i2c_client *i2c) { struct adv7511 *adv7511 = i2c_get_clientdata(i2c);
- i2c_unregister_device(adv7511->i2c_cec); - clk_disable_unprepare(adv7511->cec_clk); - adv7511_uninit_regulators(adv7511);
drm_bridge_remove(&adv7511->bridge); @@ -1349,6 +1346,8 @@ static int adv7511_remove(struct i2c_client *i2c) adv7511_audio_exit(adv7511);
cec_unregister_adapter(adv7511->cec_adap); + i2c_unregister_device(adv7511->i2c_cec); + clk_disable_unprepare(adv7511->cec_clk);
i2c_unregister_device(adv7511->i2c_packet); i2c_unregister_device(adv7511->i2c_edid);