Re: [PATCH v2 4/4] openrisc: Add Kretprobes
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From: sashiko-bot@kernel.org
Date: 2026-09-30 20:41:16
Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider: - [High] openrisc: kretprobe trampoline leaves regs->sp and regs->sr uninitialized -- commit a5e8b19fd4705325db24ad7195d2d69f741fc493 Author: Sahil Siddiq [off-list ref] openrisc: Add Kretprobes This commit adds Kretprobes support for OpenRISC by building on top of the generic rethook framework. It implements the necessary trampoline routines to intercept function returns and route them through the kretprobe handler.
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diff --git a/arch/openrisc/kernel/rethook_trampoline.S b/arch/openrisc/kernel/rethook_trampoline.S new file mode 100644 index 0000000000000..ac4ca0ecc6694 --- /dev/null +++ b/arch/openrisc/kernel/rethook_trampoline.S
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+ .text + + .macro save_all_base_regs + l.sw PT_GPR2(r1),r2 + l.sw PT_GPR3(r1),r3
[Severity: High] Does this macro need to save the stack pointer (r1) to the PT_SP offset and the status register to the PT_SR offset? It appears they are omitted from the base register save list. [ ... ]
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+SYM_CODE_START(arch_rethook_trampoline) + /* Allocate enough space on stack for pt_regs */ + l.addi r1,r1,-PT_SIZE + save_all_base_regs + + l.addi r3,r1,0 /* pt_regs */ + l.jal arch_rethook_trampoline_callback
[Severity: High] Since save_all_base_regs skips saving r1 (sp) and sr, will the pt_regs passed into arch_rethook_trampoline_callback contain uninitialized stack garbage for regs->sp and regs->sr? Tracing handlers like BPF or ftrace rely on functions like kernel_stack_pointer() and user_mode() which read these fields. Could these uninitialized fields lead to broken stack unwinding or incorrect privilege evaluation when the kretprobe handlers run? -- Sashiko AI review · https://sashiko.dev/#/patchset/20260930203129.51048-1-sahilcdq0@gmail.com?part=4