Messages in this thread | | | Date | Fri, 09 Nov 2007 16:27:32 -0800 | From | Jeremy Fitzhardinge <> | Subject | problem with x86-prepare-kprobes-code-for-unification.patch |
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Hi,
This code in kprobes_64.c from x86-prepare-kprobes-code-for-unification.patch is problematic:
+static __always_inline int is_IF_modifier(kprobe_opcode_t *insn) +{ + switch (*insn) { + case 0xfa: /* cli */ + case 0xfb: /* sti */ + case 0xcf: /* iret/iretd */ + case 0x9d: /* popf/popfd */ + return 1; + } + + /* + * on 64 bit x86, 0x40-0x4f are prefixes so we need to look + * at the next byte instead.. but of course not recurse infinitely + */ + if (*insn >= 0x40 && *insn <= 0x4f && *insn > 0x4f) + return is_IF_modifier(++insn); + return 0; +}
Firstly, the conditional in the if() doesn't seem to make much sense. It appears to be miscopied from:
- if (*insn >= 0x40 && *insn <= 0x4f && *++insn == 0xcf) - return 1;
Secondly, the recursive inlining is making 4.0.2 complain:
/home/jeremy/hg/xen/paravirt/linux/arch/x86/kernel/kprobes_64.c: In function 'set_current_kprobe': /home/jeremy/hg/xen/paravirt/linux/arch/x86/kernel/kprobes_64.c:152: sorry, unimplemented: inlining failed in call to 'is_IF_modifier': recursive inlining /home/jeremy/hg/xen/paravirt/linux/arch/x86/kernel/kprobes_64.c:166: sorry, unimplemented: called from here
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