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Ivan Mironov 7808363154 drm/amd/powerplay: Fix NULL dereference in lock_bus() on Vega20 w/o RAS I updated my system with Radeon VII from kernel 5.6 to kernel 5.7, and following started to happen on each boot: ... BUG: kernel NULL pointer dereference, address: 0000000000000128 ... CPU: 9 PID: 1940 Comm: modprobe Tainted: G E 5.7.2-200.im0.fc32.x86_64 #1 Hardware name: System manufacturer System Product Name/PRIME X570-P, BIOS 1407 04/02/2020 RIP: 0010:lock_bus+0x42/0x60 [amdgpu] ... Call Trace: i2c_smbus_xfer+0x3d/0xf0 i2c_default_probe+0xf3/0x130 i2c_detect.isra.0+0xfe/0x2b0 ? kfree+0xa3/0x200 ? kobject_uevent_env+0x11f/0x6a0 ? i2c_detect.isra.0+0x2b0/0x2b0 __process_new_driver+0x1b/0x20 bus_for_each_dev+0x64/0x90 ? 0xffffffffc0f34000 i2c_register_driver+0x73/0xc0 do_one_initcall+0x46/0x200 ? _cond_resched+0x16/0x40 ? kmem_cache_alloc_trace+0x167/0x220 ? do_init_module+0x23/0x260 do_init_module+0x5c/0x260 __do_sys_init_module+0x14f/0x170 do_syscall_64+0x5b/0xf0 entry_SYSCALL_64_after_hwframe+0x44/0xa9 ... Error appears when some i2c device driver tries to probe for devices using adapter registered by `smu_v11_0_i2c_eeprom_control_init()`. Code supporting this adapter requires `adev->psp.ras.ras` to be not NULL, which is true only when `amdgpu_ras_init()` detects HW support by calling `amdgpu_ras_check_supported()`. Before `9015d60c9e`, adapter was registered by -> amdgpu_device_ip_init() -> amdgpu_ras_recovery_init() -> amdgpu_ras_eeprom_init() -> smu_v11_0_i2c_eeprom_control_init() after verifying that `adev->psp.ras.ras` is not NULL in `amdgpu_ras_recovery_init()`. Currently it is registered unconditionally by -> amdgpu_device_ip_init() -> pp_sw_init() -> hwmgr_sw_init() -> vega20_smu_init() -> smu_v11_0_i2c_eeprom_control_init() Fix simply adds HW support check (ras == NULL => no support) before calling `smu_v11_0_i2c_eeprom_control_{init,fini}()`. Please note that there is a chance that similar fix is also required for CHIP_ARCTURUS. I do not know whether any actual Arcturus hardware without RAS exist, and whether calling `smu_i2c_eeprom_init()` makes any sense when there is no HW support. Cc: stable@vger.kernel.org Fixes: `9015d60c9e` ("drm/amdgpu: Move EEPROM I2C adapter to amdgpu_device") Signed-off-by: Ivan Mironov <mironov.ivan@gmail.com> Tested-by: Bjorn Nostvold <bjorn.nostvold@gmail.com> Signed-off-by: Alex Deucher <alexander.deucher@amd.com>		2020-07-01 01:59:27 -04:00
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Documentation	drm/amdgpu: fix documentation around busy_percentage	2020-07-01 01:59:21 -04:00
drivers	drm/amd/powerplay: Fix NULL dereference in lock_bus() on Vega20 w/o RAS	2020-07-01 01:59:27 -04:00
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include	drm/amdgpu: add sienna_cichlid asic type	2020-06-03 13:51:56 -04:00
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MAINTAINERS	R-Car Display Unit & related changes:	2020-05-14 13:41:51 +10:00
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README

Linux kernel
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There are several guides for kernel developers and users. These guides can
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There are various text files in the Documentation/ subdirectory,
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Please read the Documentation/process/changes.rst file, as it contains the
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