Re: [PATCH v3 4/8] fprobe: rethook: Use ftrace_regs in fprobe exit handler and rethook
From: Florent Revest <hidden>
Date: 2023-08-17 08:58:30
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On Sat, Aug 12, 2023 at 7:37 AM Masami Hiramatsu (Google) [off-list ref] wrote:
quoted hunk ↗ jump to hunk
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig index 976fd594b446..d56304276318 100644 --- a/kernel/trace/Kconfig +++ b/kernel/trace/Kconfig@@ -57,6 +57,13 @@ config HAVE_DYNAMIC_FTRACE_WITH_ARGS This allows for use of ftrace_regs_get_argument() and ftrace_regs_get_stack_pointer(). +config HAVE_PT_REGS_TO_FTRACE_REGS_CAST + bool + help + If this is set, the memory layout of the ftrace_regs data structure + is the same as the pt_regs. So the pt_regs is possible to be casted + to ftrace_regs.
What would you think of introducing a: #ifdef HAVE_PT_REGS_TO_FTRACE_REGS_CAST static_assert(sizeof(struct pt_regs) == sizeof(struct ftrace_regs); #endif // HAVE_PT_REGS_TO_FTRACE_REGS_CAST somewhere in ftrace.h just as a small extra safety net ? It doesn't exactly guarantee all we want but it should give an early warning of mistakes.