From: Masami Hiramatsu <mhiramat@kernel.org>
To: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>,
Ingo Molnar <mingo@kernel.org>, X86 ML <x86@kernel.org>,
Daniel Xu <dxu@dxuuu.xyz>,
linux-kernel@vger.kernel.org, bpf@vger.kernel.org,
kuba@kernel.org, mingo@redhat.com, ast@kernel.org,
tglx@linutronix.de, kernel-team@fb.com, yhs@fb.com,
Josh Poimboeuf <jpoimboe@redhat.com>,
linux-ia64@vger.kernel.org
Subject: Re: [PATCH -tip v3 05/11] x86/kprobes: Add UNWIND_HINT_FUNC on kretprobe_trampoline code
Date: Sat, 20 Mar 2021 21:16:16 +0900 [thread overview]
Message-ID: <20210320211616.a976fc66d0c51e13d3121e2f@kernel.org> (raw)
In-Reply-To: <161615655969.306069.4545805781593088526.stgit@devnote2>
On Fri, 19 Mar 2021 21:22:39 +0900
Masami Hiramatsu <mhiramat@kernel.org> wrote:
> From: Josh Poimboeuf <jpoimboe@redhat.com>
>
> 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@redhat.com>
> ---
> [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@kernel.org>
next prev parent reply other threads:[~2021-03-20 12:16 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-19 12:21 [PATCH -tip v3 00/11] kprobes: Fix stacktrace with kretprobes on x86 Masami Hiramatsu
2021-03-19 12:21 ` [PATCH -tip v3 01/11] ia64: kprobes: Fix to pass correct trampoline address to the handler Masami Hiramatsu
2021-03-19 12:22 ` [PATCH -tip v3 02/11] kprobes: treewide: Replace arch_deref_entry_point() with dereference_function_descriptor() Masami Hiramatsu
2021-03-19 12:22 ` [PATCH -tip v3 03/11] kprobes: treewide: Remove trampoline_address from kretprobe_trampoline_handler() Masami Hiramatsu
2021-03-19 12:22 ` [PATCH -tip v3 04/11] kprobes: Add kretprobe_find_ret_addr() for searching return address Masami Hiramatsu
2021-03-19 12:22 ` [PATCH -tip v3 05/11] x86/kprobes: Add UNWIND_HINT_FUNC on kretprobe_trampoline code Masami Hiramatsu
2021-03-20 12:16 ` Masami Hiramatsu [this message]
2021-03-20 13:05 ` Masami Hiramatsu
2021-03-21 17:52 ` Josh Poimboeuf
2021-03-22 0:08 ` Masami Hiramatsu
2021-03-21 17:50 ` Josh Poimboeuf
2021-03-19 12:22 ` [PATCH -tip v3 06/11] ARC: Add instruction_pointer_set() API Masami Hiramatsu
2021-03-19 12:23 ` [PATCH -tip v3 07/11] ia64: " Masami Hiramatsu
2021-03-20 1:04 ` Masami Hiramatsu
2021-03-19 12:23 ` [PATCH -tip v3 08/11] kprobes: Setup instruction pointer in __kretprobe_trampoline_handler Masami Hiramatsu
2021-03-21 12:54 ` Masami Hiramatsu
2021-03-19 12:23 ` [PATCH -tip v3 09/11] x86/kprobes: Push a fake return address at kretprobe_trampoline Masami Hiramatsu
2021-03-19 12:23 ` [PATCH -tip v3 10/11] x86/unwind: Recover kretprobe trampoline entry Masami Hiramatsu
2021-03-19 12:23 ` [PATCH -tip v3 11/11] tracing: Show kretprobe unknown indicator only for kretprobe_trampoline Masami Hiramatsu
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