From a5f7a5bb3b7f28ba7e4fa246775b29a0e5537255 Mon Sep 17 00:00:00 2001 From: Jinke Han Date: Tue, 8 Sep 2026 15:37:42 +0800 Subject: x86/kprobes: Fix crash when probing CS CALL instructions When using eBPF to probe CS CALL instructions within a function, a crash can be triggered. The eBPF tool probes offset 257 of the __hrtimer_run_queues() function: <__hrtimer_run_queues+249>: nopl 0x0(%rax,%rax,1) <__hrtimer_run_queues+254>: mov %r14,%rdi <__hrtimer_run_queues+257>: cs call <__x86_indirect_thunk_r12> <__hrtimer_run_queues+263>: mov %eax,%r12d <__hrtimer_run_queues+266>: xchg %ax,%ax <__hrtimer_run_queues+268>: mov %r13,%rdi Which triggers this crash: BUG: unable to handle page fault for address: 00000000000f41c9 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page PGD 0 P4D 0 Oops: 0002 [#1] SMP NOPTI CPU: 1 PID: 0 Comm: swapper/1 Kdump: loaded Tainted: P RIP: 0010:__hrtimer_run_queues+0x106/0x230 Note that __hrtimer_run_queues+0x106 is __hrtimer_run_queues+262, which is at the 6th byte of the above CS CALL instruction. Since the CS CALL instruction occupies 6 bytes, the exception occurred in the middle of that call instruction. The root cause is that when using eBPF tools to probe in the middle of a function, a kprobe with INT3 is used as the underlying implementation. During single-step emulation of the original CALL instruction, int3_emulate_call() assumes that the probed CALL instruction is 5 bytes long. However, the actual CS-prefixed CALL instruction occupies 6 bytes, so it constructs an incorrect exception return address. When the CPU returns from the kprobe handler, the next instruction to be executed is at the address of the last byte of that CS CALL instruction. Coincidentally, starting from that address, the CPU fetches and decodes a completely different instruction, which ultimately triggers a kernel crash. Fix the issue by using the actual instruction length obtained from the instruction decoder when constructing the exception return address, rather than relying on the hardcoded CALL_INSN_SIZE macro. [ mingo: Refined the changelog ] Fixes: 6256e668b7af ("x86/kprobes: Use int3 instead of debug trap for single-step") Suggested-by: Masami Hiramatsu (Google) Signed-off-by: Jinke Han Signed-off-by: Ingo Molnar Reviewed-by: Masami Hiramatsu (Google) Acked-by: Yafang Shao Acked-by: Borislav Petkov Cc: Peter Zijlstra Link: https://patch.msgid.link/20260908073742.GA10517@didi-ThinkCentre-M920t-N000 --- Documentation/gpu/imagination/index.rst | 13 +++ Documentation/gpu/imagination/uapi.rst | 171 ++++++++++++++++++++++++++++++++ 2 files changed, 184 insertions(+) create mode 100644 Documentation/gpu/imagination/index.rst create mode 100644 Documentation/gpu/imagination/uapi.rst (limited to 'Documentation/gpu/imagination') diff --git a/Documentation/gpu/imagination/index.rst b/Documentation/gpu/imagination/index.rst new file mode 100644 index 000000000..0c1e247ce --- /dev/null +++ b/Documentation/gpu/imagination/index.rst @@ -0,0 +1,13 @@ +======================================= +drm/imagination PowerVR Graphics Driver +======================================= + +.. kernel-doc:: drivers/gpu/drm/imagination/pvr_drv.c + :doc: PowerVR (Series 6 and later) and IMG Graphics Driver + +Contents +======== +.. toctree:: + :maxdepth: 2 + + uapi diff --git a/Documentation/gpu/imagination/uapi.rst b/Documentation/gpu/imagination/uapi.rst new file mode 100644 index 000000000..7502413d0 --- /dev/null +++ b/Documentation/gpu/imagination/uapi.rst @@ -0,0 +1,171 @@ +==== +UAPI +==== +The sources associated with this section can be found in ``pvr_drm.h``. + +.. kernel-doc:: include/uapi/drm/pvr_drm.h + :doc: PowerVR UAPI + +OBJECT ARRAYS +============= +.. kernel-doc:: include/uapi/drm/pvr_drm.h + :identifiers: drm_pvr_obj_array + +.. kernel-doc:: include/uapi/drm/pvr_drm.h + :identifiers: DRM_PVR_OBJ_ARRAY + +IOCTLS +====== +.. kernel-doc:: include/uapi/drm/pvr_drm.h + :doc: PowerVR IOCTL interface + +.. kernel-doc:: include/uapi/drm/pvr_drm.h + :identifiers: PVR_IOCTL + +DEV_QUERY +--------- +.. kernel-doc:: include/uapi/drm/pvr_drm.h + :doc: PowerVR IOCTL DEV_QUERY interface + +.. kernel-doc:: include/uapi/drm/pvr_drm.h + :identifiers: drm_pvr_dev_query + +.. kernel-doc:: include/uapi/drm/pvr_drm.h + :identifiers: drm_pvr_ioctl_dev_query_args + +.. kernel-doc:: include/uapi/drm/pvr_drm.h + :identifiers: drm_pvr_dev_query_gpu_info + drm_pvr_dev_query_runtime_info + drm_pvr_dev_query_hwrt_info + drm_pvr_dev_query_quirks + drm_pvr_dev_query_enhancements + +.. kernel-doc:: include/uapi/drm/pvr_drm.h + :identifiers: drm_pvr_heap_id + drm_pvr_heap + drm_pvr_dev_query_heap_info + +.. kernel-doc:: include/uapi/drm/pvr_drm.h + :identifiers: drm_pvr_static_data_area_usage + drm_pvr_static_data_area + drm_pvr_dev_query_static_data_areas + +CREATE_BO +--------- +.. kernel-doc:: include/uapi/drm/pvr_drm.h + :doc: PowerVR IOCTL CREATE_BO interface + +.. kernel-doc:: include/uapi/drm/pvr_drm.h + :identifiers: drm_pvr_ioctl_create_bo_args + +.. kernel-doc:: include/uapi/drm/pvr_drm.h + :doc: Flags for CREATE_BO + +GET_BO_MMAP_OFFSET +------------------ +.. kernel-doc:: include/uapi/drm/pvr_drm.h + :doc: PowerVR IOCTL GET_BO_MMAP_OFFSET interface + +.. kernel-doc:: include/uapi/drm/pvr_drm.h + :identifiers: drm_pvr_ioctl_get_bo_mmap_offset_args + +CREATE_VM_CONTEXT and DESTROY_VM_CONTEXT +---------------------------------------- +.. kernel-doc:: include/uapi/drm/pvr_drm.h + :doc: PowerVR IOCTL CREATE_VM_CONTEXT and DESTROY_VM_CONTEXT interfaces + +.. kernel-doc:: include/uapi/drm/pvr_drm.h + :identifiers: drm_pvr_ioctl_create_vm_context_args + drm_pvr_ioctl_destroy_vm_context_args + +VM_MAP and VM_UNMAP +------------------- +.. kernel-doc:: include/uapi/drm/pvr_drm.h + :doc: PowerVR IOCTL VM_MAP and VM_UNMAP interfaces + +.. kernel-doc:: include/uapi/drm/pvr_drm.h + :identifiers: drm_pvr_ioctl_vm_map_args + drm_pvr_ioctl_vm_unmap_args + +CREATE_CONTEXT and DESTROY_CONTEXT +---------------------------------- +.. kernel-doc:: include/uapi/drm/pvr_drm.h + :doc: PowerVR IOCTL CREATE_CONTEXT and DESTROY_CONTEXT interfaces + +.. kernel-doc:: include/uapi/drm/pvr_drm.h + :identifiers: drm_pvr_ioctl_create_context_args + +.. kernel-doc:: include/uapi/drm/pvr_drm.h + :identifiers: drm_pvr_ctx_priority + drm_pvr_ctx_type + drm_pvr_static_render_context_state + drm_pvr_static_render_context_state_format + drm_pvr_reset_framework + drm_pvr_reset_framework_format + +.. kernel-doc:: include/uapi/drm/pvr_drm.h + :identifiers: drm_pvr_ioctl_destroy_context_args + +CREATE_FREE_LIST and DESTROY_FREE_LIST +-------------------------------------- +.. kernel-doc:: include/uapi/drm/pvr_drm.h + :doc: PowerVR IOCTL CREATE_FREE_LIST and DESTROY_FREE_LIST interfaces + +.. kernel-doc:: include/uapi/drm/pvr_drm.h + :identifiers: drm_pvr_ioctl_create_free_list_args + +.. kernel-doc:: include/uapi/drm/pvr_drm.h + :identifiers: drm_pvr_ioctl_destroy_free_list_args + +CREATE_HWRT_DATASET and DESTROY_HWRT_DATASET +-------------------------------------------- +.. kernel-doc:: include/uapi/drm/pvr_drm.h + :doc: PowerVR IOCTL CREATE_HWRT_DATASET and DESTROY_HWRT_DATASET interfaces + +.. kernel-doc:: include/uapi/drm/pvr_drm.h + :identifiers: drm_pvr_ioctl_create_hwrt_dataset_args + +.. kernel-doc:: include/uapi/drm/pvr_drm.h + :identifiers: drm_pvr_create_hwrt_geom_data_args + drm_pvr_create_hwrt_rt_data_args + +.. kernel-doc:: include/uapi/drm/pvr_drm.h + :identifiers: drm_pvr_ioctl_destroy_hwrt_dataset_args + +SUBMIT_JOBS +----------- +.. kernel-doc:: include/uapi/drm/pvr_drm.h + :doc: PowerVR IOCTL SUBMIT_JOBS interface + +.. kernel-doc:: include/uapi/drm/pvr_drm.h + :doc: Flags for the drm_pvr_sync_op object. + +.. kernel-doc:: include/uapi/drm/pvr_drm.h + :identifiers: drm_pvr_ioctl_submit_jobs_args + +.. kernel-doc:: include/uapi/drm/pvr_drm.h + :doc: Flags for SUBMIT_JOB ioctl geometry command. + +.. kernel-doc:: include/uapi/drm/pvr_drm.h + :doc: Flags for SUBMIT_JOB ioctl fragment command. + +.. kernel-doc:: include/uapi/drm/pvr_drm.h + :doc: Flags for SUBMIT_JOB ioctl compute command. + +.. kernel-doc:: include/uapi/drm/pvr_drm.h + :doc: Flags for SUBMIT_JOB ioctl transfer command. + +.. kernel-doc:: include/uapi/drm/pvr_drm.h + :identifiers: drm_pvr_sync_op + drm_pvr_job_type + drm_pvr_hwrt_data_ref + drm_pvr_job + +Internal notes +============== +.. kernel-doc:: drivers/gpu/drm/imagination/pvr_device.h + :doc: IOCTL validation helpers + +.. kernel-doc:: drivers/gpu/drm/imagination/pvr_device.h + :identifiers: PVR_STATIC_ASSERT_64BIT_ALIGNED PVR_IOCTL_UNION_PADDING_CHECK + pvr_ioctl_union_padding_check -- cgit v1.3.1