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 v8 10/13] x86/kprobes: Push a fake return address at kretprobe_trampoline
Date: Fri, 18 Jun 2021 16:06:56 +0900 [thread overview]
Message-ID: <162400001661.506599.5153975410607447958.stgit@devnote2> (raw)
In-Reply-To: <162399992186.506599.8457763707951687195.stgit@devnote2>
This changes x86/kretprobe stack frame on kretprobe_trampoline
a bit, which now push the kretprobe_trampoline as a fake return
address at the bottom of the stack frame. With this fix, the ORC
unwinder will see the kretprobe_trampoline as a return address.
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Suggested-by: Josh Poimboeuf <jpoimboe@redhat.com>
Tested-by: Andrii Nakryik <andrii@kernel.org>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
---
arch/x86/kernel/kprobes/core.c | 31 ++++++++++++++++++++++---------
1 file changed, 22 insertions(+), 9 deletions(-)
diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c
index 74f049b6e77f..4d040aaf969b 100644
--- a/arch/x86/kernel/kprobes/core.c
+++ b/arch/x86/kernel/kprobes/core.c
@@ -1041,28 +1041,31 @@ asm(
".global kretprobe_trampoline\n"
".type kretprobe_trampoline, @function\n"
"kretprobe_trampoline:\n"
- /* We don't bother saving the ss register */
#ifdef CONFIG_X86_64
- " pushq %rsp\n"
+ /* Push fake return address to tell the unwinder it's a kretprobe */
+ " pushq $kretprobe_trampoline\n"
UNWIND_HINT_FUNC
+ /* Save the sp-8, this will be fixed later */
+ " pushq %rsp\n"
" pushfq\n"
SAVE_REGS_STRING
" movq %rsp, %rdi\n"
" call trampoline_handler\n"
- /* Replace saved sp with true return address. */
- " movq %rax, 19*8(%rsp)\n"
RESTORE_REGS_STRING
+ " addq $8, %rsp\n"
" popfq\n"
#else
- " pushl %esp\n"
+ /* Push fake return address to tell the unwinder it's a kretprobe */
+ " pushl $kretprobe_trampoline\n"
UNWIND_HINT_FUNC
+ /* Save the sp-4, this will be fixed later */
+ " pushl %esp\n"
" pushfl\n"
SAVE_REGS_STRING
" movl %esp, %eax\n"
" call trampoline_handler\n"
- /* Replace saved sp with true return address. */
- " movl %eax, 15*4(%esp)\n"
RESTORE_REGS_STRING
+ " addl $4, %esp\n"
" popfl\n"
#endif
" ret\n"
@@ -1073,8 +1076,10 @@ NOKPROBE_SYMBOL(kretprobe_trampoline);
/*
* Called from kretprobe_trampoline
*/
-__used __visible void *trampoline_handler(struct pt_regs *regs)
+__used __visible void trampoline_handler(struct pt_regs *regs)
{
+ unsigned long *frame_pointer;
+
/* fixup registers */
regs->cs = __KERNEL_CS;
#ifdef CONFIG_X86_32
@@ -1082,8 +1087,16 @@ __used __visible void *trampoline_handler(struct pt_regs *regs)
#endif
regs->ip = (unsigned long)&kretprobe_trampoline;
regs->orig_ax = ~0UL;
+ regs->sp += sizeof(long);
+ frame_pointer = ((unsigned long *)®s->sp) + 1;
- return (void *)kretprobe_trampoline_handler(regs, ®s->sp);
+ /* Replace fake return address with real one. */
+ *frame_pointer = kretprobe_trampoline_handler(regs, frame_pointer);
+ /*
+ * Move flags to sp so that kretprobe_trapmoline can return
+ * right after popf.
+ */
+ regs->sp = regs->flags;
}
NOKPROBE_SYMBOL(trampoline_handler);
next prev parent reply other threads:[~2021-06-18 7:07 UTC|newest]
Thread overview: 57+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-18 7:05 [PATCH -tip v8 00/13] kprobes: Fix stacktrace with kretprobes on x86 Masami Hiramatsu
2021-06-18 7:05 ` [PATCH -tip v8 01/13] ia64: kprobes: Fix to pass correct trampoline address to the handler Masami Hiramatsu
2021-07-05 7:46 ` Ingo Molnar
2021-07-05 10:05 ` Masami Hiramatsu
2021-06-18 7:05 ` [PATCH -tip v8 02/13] kprobes: treewide: Replace arch_deref_entry_point() with dereference_symbol_descriptor() Masami Hiramatsu
2021-07-05 7:48 ` Ingo Molnar
2021-07-05 12:03 ` Masami Hiramatsu
2021-07-07 18:28 ` Andrii Nakryiko
2021-07-08 4:08 ` Masami Hiramatsu
2021-06-18 7:05 ` [PATCH -tip v8 03/13] kprobes: treewide: Remove trampoline_address from kretprobe_trampoline_handler() Masami Hiramatsu
2021-07-05 7:03 ` Ingo Molnar
2021-07-05 10:03 ` Masami Hiramatsu
2021-07-05 7:49 ` Ingo Molnar
2021-06-18 7:05 ` [PATCH -tip v8 04/13] kprobes: Add kretprobe_find_ret_addr() for searching return address Masami Hiramatsu
2021-07-05 7:42 ` Ingo Molnar
2021-07-05 14:11 ` Masami Hiramatsu
2021-06-18 7:06 ` [PATCH -tip v8 05/13] x86/kprobes: Add UNWIND_HINT_FUNC on kretprobe_trampoline code Masami Hiramatsu
2021-07-05 8:02 ` Ingo Molnar
2021-07-09 15:31 ` Masami Hiramatsu
2021-07-10 1:41 ` Masami Hiramatsu
2021-07-10 19:01 ` Josh Poimboeuf
2021-07-10 19:24 ` [PATCH 1/2] objtool: Add frame-pointer-specific function ignore Josh Poimboeuf
2021-07-11 1:16 ` Masami Hiramatsu
2021-07-29 2:31 ` Masami Hiramatsu
2021-07-10 19:25 ` [PATCH 2/2] objtool: Ignore unwind hints for ignored functions Josh Poimboeuf
2021-07-11 2:07 ` Masami Hiramatsu
2021-06-18 7:06 ` [PATCH -tip v8 06/13] ARC: Add instruction_pointer_set() API Masami Hiramatsu
2021-06-18 7:06 ` [PATCH -tip v8 07/13] ia64: " Masami Hiramatsu
2021-06-18 7:06 ` [PATCH -tip v8 08/13] arm: kprobes: Make a space for regs->ARM_pc at kretprobe_trampoline Masami Hiramatsu
2021-07-05 8:04 ` Ingo Molnar
2021-07-05 14:40 ` Masami Hiramatsu
2021-06-18 7:06 ` [PATCH -tip v8 09/13] kprobes: Enable stacktrace from pt_regs in kretprobe handler Masami Hiramatsu
2021-06-18 14:04 ` Josh Poimboeuf
2021-06-18 7:06 ` Masami Hiramatsu [this message]
2021-07-05 8:17 ` [PATCH -tip v8 10/13] x86/kprobes: Push a fake return address at kretprobe_trampoline Ingo Molnar
2021-07-09 14:55 ` Masami Hiramatsu
2021-06-18 7:07 ` [PATCH -tip v8 11/13] x86/unwind: Recover kretprobe trampoline entry Masami Hiramatsu
2021-07-05 11:36 ` Peter Zijlstra
2021-07-05 15:42 ` Masami Hiramatsu
2021-07-06 7:55 ` Peter Zijlstra
2021-07-06 15:11 ` Steven Rostedt
2021-07-07 8:20 ` Peter Zijlstra
2021-07-07 8:36 ` Peter Zijlstra
2021-07-07 10:15 ` Masami Hiramatsu
2021-07-07 10:20 ` Peter Zijlstra
2021-07-07 10:45 ` Masami Hiramatsu
2021-07-07 13:29 ` Masami Hiramatsu
2021-07-07 14:42 ` Matt Wu
2021-07-11 14:09 ` Masami Hiramatsu
2021-07-11 15:28 ` Matt Wu
2021-07-12 4:57 ` Masami Hiramatsu
2021-06-18 7:07 ` [PATCH -tip v8 12/13] tracing: Show kretprobe unknown indicator only for kretprobe_trampoline Masami Hiramatsu
2021-06-18 7:07 ` [PATCH -tip v8 13/13] x86/kprobes: Fixup return address in generic trampoline handler Masami Hiramatsu
2021-07-05 8:34 ` Ingo Molnar
2021-07-06 12:57 ` Masami Hiramatsu
2021-06-18 17:44 ` [PATCH -tip v8 00/13] kprobes: Fix stacktrace with kretprobes on x86 Andrii Nakryiko
2021-06-28 13:50 ` Masami Hiramatsu
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=162400001661.506599.5153975410607447958.stgit@devnote2 \
--to=mhiramat@kernel.org \
--cc=andrii.nakryiko@gmail.com \
--cc=ast@kernel.org \
--cc=bp@alien8.de \
--cc=bpf@vger.kernel.org \
--cc=dxu@dxuuu.xyz \
--cc=jpoimboe@redhat.com \
--cc=kernel-team@fb.com \
--cc=kuba@kernel.org \
--cc=linux-ia64@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@kernel.org \
--cc=mingo@redhat.com \
--cc=peterz@infradead.org \
--cc=rostedt@goodmis.org \
--cc=sagar.abhishek@gmail.com \
--cc=tglx@linutronix.de \
--cc=x86@kernel.org \
--cc=yhs@fb.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).