x86/kprobes: Prohibit probing on compiler generated CFI checking code
Prohibit probing on the compiler generated CFI typeid checking code because it is used for decoding typeid when CFI error happens. The compiler generates the following instruction sequence for indirect call checks on x86; movl -<id>, %r10d ; 6 bytes addl -4(%reg), %r10d ; 4 bytes je .Ltmp1 ; 2 bytes ud2 ; <- regs->ip And handle_cfi_failure() decodes these instructions (movl and addl) for the typeid and the target address. Thus if we put a kprobe on those instructions, the decode will fail and report a wrong typeid and target address. Signed-off-by:Masami Hiramatsu (Google) <mhiramat@kernel.org> Signed-off-by:
Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/168904025785.116016.12766408611437534723.stgit@devnote2
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