From: Masami Hiramatsu <mhiramat@kernel.org>
To: Steven Rostedt <rostedt@goodmis.org>,
Josh Poimboeuf <jpoimboe@redhat.com>,
Ingo Molnar <mingo@kernel.org>
Cc: X86 ML <x86@kernel.org>, Masami Hiramatsu <mhiramat@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,
Thomas Gleixner <tglx@linutronix.de>,
Borislav Petkov <bp@alien8.de>,
Peter Zijlstra <peterz@infradead.org>,
kernel-team@fb.com, yhs@fb.com, linux-ia64@vger.kernel.org,
Abhishek Sagar <sagar.abhishek@gmail.com>,
Andrii Nakryiko <andrii.nakryiko@gmail.com>
Subject: [PATCH -tip v10 08/16] x86/kprobes: Add UNWIND_HINT_FUNC on kretprobe_trampoline()
Date: Thu, 29 Jul 2021 23:07:11 +0900 [thread overview]
Message-ID: <162756763152.301564.15938185070079124398.stgit@devnote2> (raw)
In-Reply-To: <162756755600.301564.4957591913842010341.stgit@devnote2>
From: Josh Poimboeuf <jpoimboe@redhat.com>
Add UNWIND_HINT_FUNC on __kretprobe_trampoline() code so that ORC
information is generated on the __kretprobe_trampoline() correctly.
Also, this uses STACK_FRAME_NON_STANDARD_FP(), CONFIG_FRAME_POINTER-
-specific version of STACK_FRAME_NON_STANDARD().
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Tested-by: Andrii Nakryiko <andrii@kernel.org>
---
Changes in v9:
- Update changelog and fix comment.
- Use STACK_FRAME_NON_STANDARD_FP().
Changes in v4:
- Apply UNWIND_HINT_FUNC only if CONFIG_FRAME_POINTER=n.
---
arch/x86/include/asm/unwind_hints.h | 5 +++++
arch/x86/kernel/kprobes/core.c | 13 +++++++++++--
2 files changed, 16 insertions(+), 2 deletions(-)
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 79cd23dba5b5..d1436d7463fd 100644
--- a/arch/x86/kernel/kprobes/core.c
+++ b/arch/x86/kernel/kprobes/core.c
@@ -1025,6 +1025,7 @@ 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"
@@ -1035,6 +1036,7 @@ asm(
" popfq\n"
#else
" pushl %esp\n"
+ UNWIND_HINT_FUNC
" pushfl\n"
SAVE_REGS_STRING
" movl %esp, %eax\n"
@@ -1048,8 +1050,15 @@ asm(
".size __kretprobe_trampoline, .-__kretprobe_trampoline\n"
);
NOKPROBE_SYMBOL(__kretprobe_trampoline);
-STACK_FRAME_NON_STANDARD(__kretprobe_trampoline);
-
+/*
+ * __kretprobe_trampoline() skips updating frame pointer. The frame pointer
+ * saved in trampoline_handler() points to the real caller function's
+ * frame pointer. Thus the __kretprobe_trampoline() doesn't have a
+ * standard stack frame with CONFIG_FRAME_POINTER=y.
+ * Let's mark it non-standard function. Anyway, FP unwinder can correctly
+ * unwind without the hint.
+ */
+STACK_FRAME_NON_STANDARD_FP(__kretprobe_trampoline);
/*
* Called from __kretprobe_trampoline
next prev parent reply other threads:[~2021-07-29 14:09 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-29 14:05 [PATCH -tip v10 00/16] kprobes: Fix stacktrace with kretprobes on x86 Masami Hiramatsu
2021-07-29 14:06 ` [PATCH -tip v10 01/16] ia64: kprobes: Fix to pass correct trampoline address to the handler Masami Hiramatsu
2021-07-29 14:06 ` [PATCH -tip v10 02/16] kprobes: treewide: Replace arch_deref_entry_point() with dereference_symbol_descriptor() Masami Hiramatsu
2021-07-29 14:06 ` [PATCH -tip v10 03/16] kprobes: treewide: Remove trampoline_address from kretprobe_trampoline_handler() Masami Hiramatsu
2021-07-29 14:06 ` [PATCH -tip v10 04/16] kprobes: treewide: Make it harder to refer kretprobe_trampoline directly Masami Hiramatsu
2021-07-29 14:06 ` [PATCH -tip v10 05/16] kprobes: Add kretprobe_find_ret_addr() for searching return address Masami Hiramatsu
2021-07-29 14:06 ` [PATCH -tip v10 06/16] objtool: Add frame-pointer-specific function ignore Masami Hiramatsu
2021-07-29 14:07 ` [PATCH -tip v10 07/16] objtool: Ignore unwind hints for ignored functions Masami Hiramatsu
2021-07-29 14:07 ` Masami Hiramatsu [this message]
2021-07-29 14:07 ` [PATCH -tip v10 09/16] ARC: Add instruction_pointer_set() API Masami Hiramatsu
2021-07-29 14:07 ` [PATCH -tip v10 10/16] ia64: " Masami Hiramatsu
2021-07-29 14:07 ` [PATCH -tip v10 11/16] arm: kprobes: Make space for instruction pointer on stack Masami Hiramatsu
2021-07-29 14:07 ` [PATCH -tip v10 12/16] kprobes: Enable stacktrace from pt_regs in kretprobe handler Masami Hiramatsu
2021-07-29 14:07 ` [PATCH -tip v10 13/16] x86/kprobes: Push a fake return address at kretprobe_trampoline Masami Hiramatsu
2021-07-29 14:08 ` [PATCH -tip v10 14/16] x86/unwind: Recover kretprobe trampoline entry Masami Hiramatsu
2021-07-29 14:08 ` [PATCH -tip v10 15/16] tracing: Show kretprobe unknown indicator only for kretprobe_trampoline Masami Hiramatsu
2021-07-29 14:08 ` [PATCH -tip v10 16/16] x86/kprobes: Fixup return address in generic trampoline handler Masami Hiramatsu
2021-07-29 23:35 ` [PATCH -tip v10 00/16] kprobes: Fix stacktrace with kretprobes on x86 Masami Hiramatsu
2021-08-24 5:12 ` Andrii Nakryiko
2021-08-24 5:32 ` Masami Hiramatsu
2021-09-13 17:14 ` Andrii Nakryiko
2021-09-14 0:38 ` Masami Hiramatsu
2021-09-14 1:36 ` Andrii Nakryiko
2021-09-14 5:10 ` Masami Hiramatsu
2021-08-29 14:22 ` [RFC PATCH 0/1] Non stack-intrusive return probe event Masami Hiramatsu
2021-08-29 14:22 ` [RFC PATCH 1/1] [PoC] tracing: kprobe: Add non-stack intrusion " Masami Hiramatsu
2021-08-30 19:04 ` [RFC PATCH 0/1] Non stack-intrusive " Andrii Nakryiko
2021-08-31 6:06 ` Masami Hiramatsu
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