From: Srinivasan Shanmugam <srinivasan.shanmugam@amd.com> stable inclusion from stable-v6.19.4 commit a490e4d3c9fed1e690c8de348416eea3a9f054ff category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/15520 CVE: CVE-2026-46245 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- [ Upstream commit 226a40c06a183abaeb7529a4f54d6c203bd14407 ] amdgpu_dm_hpd_init() may see connectors without a valid dc_link. The code already checks dc_link for the polling decision, but later unconditionally dereferences it when setting up HPD interrupts. Assign dc_link early and skip connectors where it is NULL. Fixes the below: drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm_irq.c:940 amdgpu_dm_hpd_init() error: we previously assumed 'dc_link' could be null (see line 931) drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm_irq.c 923 /* 924 * Analog connectors may be hot-plugged unlike other connector 925 * types that don't support HPD. Only poll analog connectors. 926 */ 927 use_polling |= 928 amdgpu_dm_connector->dc_link && ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ The patch adds this NULL check but hopefully it can be removed 929 dc_connector_supports_analog(amdgpu_dm_connector->dc_link->link_id.id); 930 931 dc_link = amdgpu_dm_connector->dc_link; dc_link assigned here. 932 933 /* 934 * Get a base driver irq reference for hpd ints for the lifetime 935 * of dm. Note that only hpd interrupt types are registered with 936 * base driver; hpd_rx types aren't. IOW, amdgpu_irq_get/put on 937 * hpd_rx isn't available. DM currently controls hpd_rx 938 * explicitly with dc_interrupt_set() 939 */ --> 940 if (dc_link->irq_source_hpd != DC_IRQ_SOURCE_INVALID) { ^^^^^^^^^^^^^^^^^^^^^^^ If it's NULL then we are trouble because we dereference it here. 941 irq_type = dc_link->irq_source_hpd - DC_IRQ_SOURCE_HPD1; 942 /* 943 * TODO: There's a mismatch between mode_info.num_hpd 944 * and what bios reports as the # of connectors with hpd Fixes: 4562236b3bc0 ("drm/amd/dc: Add dc display driver (v2)") Cc: Timur Kristóf <timur.kristof@gmail.com> Cc: Harry Wentland <harry.wentland@amd.com> Cc: Mario Limonciello <superm1@kernel.org> Cc: Alex Hung <alex.hung@amd.com> Cc: Aurabindo Pillai <aurabindo.pillai@amd.com> Cc: ChiaHsuan Chung <chiahsuan.chung@amd.com> Cc: Roman Li <roman.li@amd.com> Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Srinivasan Shanmugam <srinivasan.shanmugam@amd.com> Reviewed-by: Timur Kristóf <timur.kristof@gmail.com> Signed-off-by: Alex Deucher <alexander.deucher@amd.com> Signed-off-by: Sasha Levin <sashal@kernel.org> Conflicts: drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_irq.c [Fanhua Li: context conflict] Signed-off-by: Fanhua Li <lifanhua5@huawei.com> --- drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_irq.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_irq.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_irq.c index 29e1b252ec730..ba276d2f3af19 100644 --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_irq.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_irq.c @@ -907,6 +907,8 @@ void amdgpu_dm_hpd_init(struct amdgpu_device *adev) to_amdgpu_dm_connector(connector); const struct dc_link *dc_link = amdgpu_dm_connector->dc_link; + if (!dc_link) + continue; /* * Get a base driver irq reference for hpd ints for the lifetime -- 2.43.0