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From: Dirk Gouders <dirk@gouders.net>
To: Alex Deucher <alexander.deucher@amd.com>
Cc: "Christian König" <christian.koenig@amd.com>,
	linux-kernel@vger.kernel.org
Cc: amd-gfx@lists.freedesktop.org,
	Hawking Zhang <Hawking.Zhang@amd.com>,
	Evan Quan <evan.quan@amd.com>
Subject: BUG: amdgpu: NULL pointer dereference introduced in 5.9-rc1
Date: Wed, 30 Sep 2020 22:13:23 +0200	[thread overview]
Message-ID: <ghmu1758gs.fsf@gouders.net> (raw)

Commit c1cf79ca5ced46 (drm/amdgpu: use IP discovery table for renoir)
introduced a NULL pointer dereference when booting with
amdgpu.discovery=0.

For amdgpu.discovery=0 that commit effectively removed the call of
vega10_reg_base_init(adev), so I tested the correctness of the bisect
session by restoring that function call for amdgpu_discovery == 0 and with
that change, the NULL pointer dereference does not occur:

diff --git a/drivers/gpu/drm/amd/amdgpu/soc15.c b/drivers/gpu/drm/amd/amdgpu/soc15.c
index 84d811b6e48b..2e93c5e1e7e6 100644
--- a/drivers/gpu/drm/amd/amdgpu/soc15.c
+++ b/drivers/gpu/drm/amd/amdgpu/soc15.c
@@ -699,7 +699,8 @@ static void soc15_reg_base_init(struct amdgpu_device *adev)
                                         "fallback to legacy init method\n");
                                vega10_reg_base_init(adev);
                        }
-               }
+               } else
+                       vega10_reg_base_init(adev);
                break;
        case CHIP_VEGA20:
                vega20_reg_base_init(adev);

Dirk

             reply	other threads:[~2020-09-30 20:17 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-30 20:13 Dirk Gouders [this message]
2020-10-01 14:05 ` BUG: amdgpu: NULL pointer dereference introduced in 5.9-rc1 Alex Deucher
2020-10-01 19:55   ` [PATCH 0/1] drm/amdgpu: fix NULL pointer dereference for Renoir Dirk Gouders
2020-10-01 19:55   ` [PATCH 1/1] " Dirk Gouders
2020-10-01 20:30     ` Dirk Gouders
2020-10-01 20:47       ` Alex Deucher

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