[PATCH 5.8 157/255] drm/amdgpu: fix NULL pointer access issue when unloading driver
From: Greg Kroah-Hartman
Date: Tue Sep 01 2020 - 12:03:41 EST
From: Guchun Chen <guchun.chen@xxxxxxx>
[ Upstream commit 1a68d96f81b8e7eb2a121fbf9abf9e5974e58832 ]
When unloading driver by "modprobe -r amdgpu", one NULL pointer
dereference bug occurs in ras debugfs releasing. The cause is the
duplicated debugfs_remove, as drm debugfs_root dir has been cleaned
up already by drm_minor_unregister.
BUG: kernel NULL pointer dereference, address: 00000000000000a0
PGD 0 P4D 0
Oops: 0002 [#1] SMP PTI
CPU: 11 PID: 1526 Comm: modprobe Tainted: G OE 5.6.0-guchchen #1
Hardware name: System manufacturer System Product Name/TUF Z370-PLUS GAMING II, BIOS 0411 09/21/2018
RIP: 0010:down_write+0x15/0x40
Code: eb de e8 7e 17 72 ff cc cc cc cc cc cc cc cc cc cc cc cc cc cc 0f 1f 44 00 00 53 48 89 fb e8 92
d8 ff ff 31 c0 ba 01 00 00 00 <f0> 48 0f b1 13 75 0f 65 48 8b 04 25 c0 8b 01 00 48 89 43 08 5b c3
RSP: 0018:ffffb1590386fcd0 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 00000000000000a0 RCX: 0000000000000000
RDX: 0000000000000001 RSI: ffffffff85b2fcc2 RDI: 00000000000000a0
RBP: ffffb1590386fd30 R08: ffffffff85b2fcc2 R09: 000000000002b3c0
R10: ffff97a330618c40 R11: 00000000000005f6 R12: ffff97a3481beb40
R13: 00000000000000a0 R14: ffff97a3481beb40 R15: 0000000000000000
FS: 00007fb11a717540(0000) GS:ffff97a376cc0000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000000000a0 CR3: 00000004066d6006 CR4: 00000000003606e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
simple_recursive_removal+0x63/0x370
? debugfs_remove+0x60/0x60
debugfs_remove+0x40/0x60
amdgpu_ras_fini+0x82/0x230 [amdgpu]
? __kernfs_remove.part.17+0x101/0x1f0
? kernfs_name_hash+0x12/0x80
amdgpu_device_fini+0x1c0/0x580 [amdgpu]
amdgpu_driver_unload_kms+0x3e/0x70 [amdgpu]
amdgpu_pci_remove+0x36/0x60 [amdgpu]
pci_device_remove+0x3b/0xb0
device_release_driver_internal+0xe5/0x1c0
driver_detach+0x46/0x90
bus_remove_driver+0x58/0xd0
pci_unregister_driver+0x29/0x90
amdgpu_exit+0x11/0x25 [amdgpu]
__x64_sys_delete_module+0x13d/0x210
do_syscall_64+0x5f/0x250
entry_SYSCALL_64_after_hwframe+0x44/0xa9
Signed-off-by: Guchun Chen <guchun.chen@xxxxxxx>
Reviewed-by: Tao Zhou <tao.zhou1@xxxxxxx>
Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c | 2 --
1 file changed, 2 deletions(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c
index 20a7d75b2eb88..3f47f35eedff1 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c
@@ -1240,7 +1240,6 @@ void amdgpu_ras_debugfs_remove(struct amdgpu_device *adev,
if (!obj || !obj->ent)
return;
- debugfs_remove(obj->ent);
obj->ent = NULL;
put_obj(obj);
}
@@ -1254,7 +1253,6 @@ static void amdgpu_ras_debugfs_remove_all(struct amdgpu_device *adev)
amdgpu_ras_debugfs_remove(adev, &obj->head);
}
- debugfs_remove_recursive(con->dir);
con->dir = NULL;
}
/* debugfs end */
--
2.25.1