On Fri, 19 Mar 2021 21:22:39 +0900 Masami Hiramatsu <mhiramat@xxxxxxxxxx> wrote: > From: Josh Poimboeuf <jpoimboe@xxxxxxxxxx> > > Add UNWIND_HINT_FUNC on kretporbe_trampoline code so that ORC > information is generated on the kretprobe_trampoline correctly. > Test bot also found a new warning for this. > >> arch/x86/kernel/kprobes/core.o: warning: objtool: kretprobe_trampoline()+0x25: call without frame pointer save/setup With CONFIG_FRAME_POINTER=y. Of course this can be fixed with additional "push %bp; mov %sp, %bp" before calling trampoline_handler. But actually we know that this function has a bit special stack frame too. Can I recover STACK_FRAME_NON_STANDARD(kretprobe_trampoline) when CONFIG_FRAME_POINTER=y ? Thank you, > Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx> > --- > [MH] Add patch description. > --- > arch/x86/include/asm/unwind_hints.h | 5 +++++ > arch/x86/kernel/kprobes/core.c | 3 ++- > 2 files changed, 7 insertions(+), 1 deletion(-) > > diff --git a/arch/x86/include/asm/unwind_hints.h b/arch/x86/include/asm/unwind_hints.h > index 8e574c0afef8..8b33674288ea 100644 > --- a/arch/x86/include/asm/unwind_hints.h > +++ b/arch/x86/include/asm/unwind_hints.h > @@ -52,6 +52,11 @@ > UNWIND_HINT sp_reg=ORC_REG_SP sp_offset=8 type=UNWIND_HINT_TYPE_FUNC > .endm > > +#else > + > +#define UNWIND_HINT_FUNC \ > + UNWIND_HINT(ORC_REG_SP, 8, UNWIND_HINT_TYPE_FUNC, 0) > + > #endif /* __ASSEMBLY__ */ > > #endif /* _ASM_X86_UNWIND_HINTS_H */ > diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c > index 427d648fffcd..b31058a152b6 100644 > --- a/arch/x86/kernel/kprobes/core.c > +++ b/arch/x86/kernel/kprobes/core.c > @@ -772,6 +772,7 @@ asm( > /* We don't bother saving the ss register */ > #ifdef CONFIG_X86_64 > " pushq %rsp\n" > + UNWIND_HINT_FUNC > " pushfq\n" > SAVE_REGS_STRING > " movq %rsp, %rdi\n" > @@ -782,6 +783,7 @@ asm( > " popfq\n" > #else > " pushl %esp\n" > + UNWIND_HINT_FUNC > " pushfl\n" > SAVE_REGS_STRING > " movl %esp, %eax\n" > @@ -795,7 +797,6 @@ asm( > ".size kretprobe_trampoline, .-kretprobe_trampoline\n" > ); > NOKPROBE_SYMBOL(kretprobe_trampoline); > -STACK_FRAME_NON_STANDARD(kretprobe_trampoline); > > > /* > -- Masami Hiramatsu <mhiramat@xxxxxxxxxx>
