Fix the failure issue of the module_attach test case #10473
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December 12, 2025 01:20
Refactor the register restoration sequence in the ftrace_common_return function to clearly distinguish between the logic of normal returns and direct call returns in function tracing scenarios. The logic is as follows: 1. In the case of a normal return, the execution flow returns to the traced function, and ftrace must ensure that the register data is consistent with the state when the function was entered. ra = parent return address; t0 = traced function return address. 2. In the case of a direct call return, the execution flow jumps to the custom trampoline function, and ftrace must ensure that the register data is consistent with the state when ftrace was entered. ra = traced function return address; t0 = parent return address. Fixes: 9cdc3b6 ("LoongArch: ftrace: Add direct call support") Signed-off-by: Chenghao Duan <[email protected]>
…rampolines Ensure that in the ftrace direct call logic, the CPU register state (with ra = parent return address) is restored to the correct state after the execution of the custom trampoline function and before returning to the traced function. Additionally, guarantee the correctness of the jump logic for jr t0 (traced function address). Reported-by: Youling Tang <[email protected]> Signed-off-by: Chenghao Duan <[email protected]>
This patch addresses two main issues in the LoongArch BPF trampoline implementation: 1. BPF-to-BPF call handling: - Modify the build_prologue function to ensure that the value of the return address register ra is saved to t0 before entering the trampoline operation. - This ensures that the return address handling logic is accurate and error-free when a BPF program calls another BPF program. 2. Enable Module Function Tracing Support: - Remove the previous restrictions that blocked the tracing of kernel module functions. - Fix the issue that previously caused kernel lockups when attempting to trace module functions 3. Related Function Optimizations: - Adjust the jump offset of tail calls to ensure correct instruction alignment. - Enhance the bpf_arch_text_poke() function to enable accurate location of BPF program entry points. - Refine the trampoline return logic to ensure that the register data is correct when returning to both the traced function and the parent function. Signed-off-by: Chenghao Duan <[email protected]>
This patch allows the LoongArch BPF JIT to handle recoverable memory access errors generated by BPF_PROBE_MEM* instructions. When a BPF program performs memory access operations, the instructions it executes may trigger ADEM exceptions. The kernel’s built-in BPF exception table mechanism (EX_TYPE_BPF) will generate corresponding exception fixup entries in the JIT compilation phase; however, the architecture-specific trap handling function needs to proactively call the common fixup routine to achieve exception recovery. do_ade(): fix EX_TYPE_BPF memory access exceptions for BPF programs, ensure safe execution. Signed-off-by: Chenghao Duan <[email protected]>
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Upstream branch: 759377d |
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At least one diff in series https://patchwork.kernel.org/project/netdevbpf/list/?series=1032584 irrelevant now. Closing PR. |
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Pull request for series with
subject: Fix the failure issue of the module_attach test case
version: 2
url: https://patchwork.kernel.org/project/netdevbpf/list/?series=1032584