[PATCH AUTOSEL 6.6 094/139] drm/amd/display: fix double free issue during amdgpu module unload

Sasha Levin
2024-09-25T12:15:57Z

From: Tim Huang <tim.huang@amd.com>

[ Upstream commit 20b5a8f9f4670a8503aa9fa95ca632e77c6bf55d ]

Flexible endpoints use DIGs from available inflexible endpoints,
so only the encoders of inflexible links need to be freed.
Otherwise, a double free issue may occur when unloading the
amdgpu module.

[ 279.190523] RIP: 0010:__slab_free+0x152/0x2f0
[ 279.190577] Call Trace:
[ 279.190580] <TASK>
[ 279.190582] ? show_regs+0x69/0x80
[ 279.190590] ? die+0x3b/0x90
[ 279.190595] ? do_trap+0xc8/0xe0
[ 279.190601] ? do_error_trap+0x73/0xa0
[ 279.190605] ? __slab_free+0x152/0x2f0
[ 279.190609] ? exc_invalid_op+0x56/0x70
[ 279.190616] ? __slab_free+0x152/0x2f0
[ 279.190642] ? asm_exc_invalid_op+0x1f/0x30
[ 279.190648] ? dcn10_link_encoder_destroy+0x19/0x30 [amdgpu]
[ 279.191096] ? __slab_free+0x152/0x2f0
[ 279.191102] ? dcn10_link_encoder_destroy+0x19/0x30 [amdgpu]
[ 279.191469] kfree+0x260/0x2b0
[ 279.191474] dcn10_link_encoder_destroy+0x19/0x30 [amdgpu]
[ 279.191821] link_destroy+0xd7/0x130 [amdgpu]
[ 279.192248] dc_destruct+0x90/0x270 [amdgpu]
[ 279.192666] dc_destroy+0x19/0x40 [amdgpu]
[ 279.193020] amdgpu_dm_fini+0x16e/0x200 [amdgpu]
[ 279.193432] dm_hw_fini+0x26/0x40 [amdgpu]
[ 279.193795] amdgpu_device_fini_hw+0x24c/0x400 [amdgpu]
[ 279.194108] amdgpu_driver_unload_kms+0x4f/0x70 [amdgpu]
[ 279.194436] amdgpu_pci_remove+0x40/0x80 [amdgpu]
[ 279.194632] pci_device_remove+0x3a/0xa0
[ 279.194638] device_remove+0x40/0x70
[ 279.194642] device_release_driver_internal+0x1ad/0x210
[ 279.194647] driver_detach+0x4e/0xa0
[ 279.194650] bus_remove_driver+0x6f/0xf0
[ 279.194653] driver_unregister+0x33/0x60
[ 279.194657] pci_unregister_driver+0x44/0x90
[ 279.194662] amdgpu_exit+0x19/0x1f0 [amdgpu]
[ 279.194939] __do_sys_delete_module.isra.0+0x198/0x2f0
[ 279.194946] __x64_sys_delete_module+0x16/0x20
[ 279.194950] do_syscall_64+0x58/0x120
[ 279.194954] entry_SYSCALL_64_after_hwframe+0x6e/0x76
[ 279.194980] </TASK>

Reviewed-by: Rodrigo Siqueira <rodrigo.siqueira@amd.com>
Signed-off-by: Tim Huang <tim.huang@amd.com>
Reviewed-by: Roman Li <roman.li@amd.com>
Signed-off-by: Roman Li <roman.li@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/gpu/drm/amd/display/dc/link/link_factory.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/display/dc/link/link_factory.c b/drivers/gpu/drm/amd/display/dc/link/link_factory.c
index 33bb96f770b86..eb7c9f226af5c 100644
--- a/drivers/gpu/drm/amd/display/dc/link/link_factory.c
+++ b/drivers/gpu/drm/amd/display/dc/link/link_factory.c
@@ -403,7 +403,7 @@ static void link_destruct(struct dc_link *link)
if (link->panel_cntl)
link->panel_cntl->funcs->destroy(&link->panel_cntl);

- if (link->link_enc) {
+ if (link->link_enc && !link->is_dig_mapping_flexible) {
/* Update link encoder resource tracking variables. These are used for
* the dynamic assignment of link encoders to streams. Virtual links
* are not assigned encoder resources on creation.
--
2.43.0