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From: Masami Hiramatsu <mhiramat@kernel.org>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: "Naveen N . Rao" <naveen.n.rao@linux.vnet.ibm.com>,
	Ananth N Mavinakayanahalli <ananth@linux.ibm.com>,
	Ingo Molnar <mingo@kernel.org>,
	linux-kernel@vger.kernel.org, mhiramat@kernel.org,
	Sven Schnelle <svens@linux.ibm.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>,
	Russell King <linux@armlinux.org.uk>,
	Nathan Chancellor <nathan@kernel.org>,
	Nick Desaulniers <ndesaulniers@google.com>,
	linux-arm-kernel@lists.infradead.org
Subject: [PATCH v3 4/9] arm64: kprobes: Record frame pointer with kretprobe instance
Date: Thu, 21 Oct 2021 09:54:51 +0900	[thread overview]
Message-ID: <163477769080.264901.17354945239446513633.stgit@devnote2> (raw)
In-Reply-To: <163477765570.264901.3851692300287671122.stgit@devnote2>

Record the frame pointer instead of stack address with kretprobe
instance as the identifier on the instance list.
Since arm64 always enable CONFIG_FRAME_POINTER, we can use the
actual frame pointer (x29).

This will allow the stacktrace code to find the original return
address from the FP alone.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Will Deacon <will@kernel.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
---
 Changes in v2:
  - Update changelog according to Mark's comment.
---
 arch/arm64/kernel/probes/kprobes.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/kernel/probes/kprobes.c b/arch/arm64/kernel/probes/kprobes.c
index e7ad6da980e8..d9dfa82c1f18 100644
--- a/arch/arm64/kernel/probes/kprobes.c
+++ b/arch/arm64/kernel/probes/kprobes.c
@@ -401,14 +401,14 @@ int __init arch_populate_kprobe_blacklist(void)
 
 void __kprobes __used *trampoline_probe_handler(struct pt_regs *regs)
 {
-	return (void *)kretprobe_trampoline_handler(regs, (void *)kernel_stack_pointer(regs));
+	return (void *)kretprobe_trampoline_handler(regs, (void *)regs->regs[29]);
 }
 
 void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
 				      struct pt_regs *regs)
 {
 	ri->ret_addr = (kprobe_opcode_t *)regs->regs[30];
-	ri->fp = (void *)kernel_stack_pointer(regs);
+	ri->fp = (void *)regs->regs[29];
 
 	/* replace return addr (x30) with trampoline */
 	regs->regs[30] = (long)&__kretprobe_trampoline;


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  parent reply	other threads:[~2021-10-21  0:56 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-10-21  0:54 [PATCH v3 0/9] kprobes: Make KUnit and add stacktrace on kretprobe tests Masami Hiramatsu
2021-10-21  0:54 ` [PATCH v3 1/9] kprobes: convert tests to kunit Masami Hiramatsu
2021-10-21  0:54 ` [PATCH v3 2/9] kprobes: Add a test case for stacktrace from kretprobe handler Masami Hiramatsu
2021-10-22 16:15   ` Steven Rostedt
2021-10-22 18:23     ` Steven Rostedt
2021-10-25  2:34     ` Masami Hiramatsu
2021-10-21  0:54 ` [PATCH v3 3/9] x86/unwind: Compile kretprobe fixup code only if CONFIG_KRETPROBES=y Masami Hiramatsu
2021-10-21  0:54 ` Masami Hiramatsu [this message]
2021-10-21  0:55 ` [PATCH v3 5/9] arm64: kprobes: Make a frame pointer on __kretprobe_trampoline Masami Hiramatsu
2021-10-21  0:55 ` [PATCH v3 6/9] arm64: Recover kretprobe modified return address in stacktrace Masami Hiramatsu
2021-10-21 10:15   ` Will Deacon
2021-10-21 14:26     ` Masami Hiramatsu
2021-10-21 14:49       ` Steven Rostedt
2021-10-21 16:52         ` Will Deacon
2021-10-21 16:59           ` Steven Rostedt
2021-10-21 18:38             ` Steven Rostedt
2021-10-21  0:55 ` [PATCH v3 7/9] ARM: clang: Do not rely on lr register for stacktrace Masami Hiramatsu
2021-10-21  0:55 ` [PATCH v3 8/9] ARM: kprobes: Make a frame pointer on __kretprobe_trampoline Masami Hiramatsu
2021-12-03 20:37   ` Arnd Bergmann
2021-12-04  8:45     ` Ard Biesheuvel
2021-12-04 12:08       ` Arnd Bergmann
2021-12-08 12:26         ` Masami Hiramatsu
2021-10-21  0:55 ` [PATCH v3 9/9] ARM: Recover kretprobe modified return address in stacktrace Masami Hiramatsu

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