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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>,
	Paul McKenney <paulmck@kernel.org>
Subject: [PATCH -tip v11 14/27] kprobes: treewide: Remove trampoline_address from kretprobe_trampoline_handler()
Date: Tue, 14 Sep 2021 23:40:45 +0900	[thread overview]
Message-ID: <163163044546.489837.13505751885476015002.stgit@devnote2> (raw)
In-Reply-To: <163163030719.489837.2236069935502195491.stgit@devnote2>

The __kretprobe_trampoline_handler() callback, called from low level
arch kprobes methods, has the 'trampoline_address' parameter, which is
entirely superfluous as it basically just replicates:

  dereference_kernel_function_descriptor(kretprobe_trampoline)

In fact we had bugs in arch code where it wasn't replicated correctly.

So remove this superfluous parameter and use kretprobe_trampoline_addr()
instead.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Tested-by: Andrii Nakryiko <andrii@kernel.org>
---
 Changes in v9:
   - Update changelog according to Ingo's suggestion.
 Changes in v8:
   - Use dereference_kernel_function_descriptor() to
     get the kretprobe_trampoline address.
 Changes in v3:
   - Remove wrong kretprobe_trampoline declaration from
     arch/x86/include/asm/kprobes.h.
 Changes in v2:
   - Remove arch_deref_entry_point() from comment.
---
 arch/arc/kernel/kprobes.c          |    2 +-
 arch/arm/probes/kprobes/core.c     |    3 +--
 arch/arm64/kernel/probes/kprobes.c |    3 +--
 arch/csky/kernel/probes/kprobes.c  |    2 +-
 arch/ia64/kernel/kprobes.c         |    5 ++---
 arch/mips/kernel/kprobes.c         |    3 +--
 arch/parisc/kernel/kprobes.c       |    4 ++--
 arch/powerpc/kernel/kprobes.c      |    2 +-
 arch/riscv/kernel/probes/kprobes.c |    2 +-
 arch/s390/kernel/kprobes.c         |    2 +-
 arch/sh/kernel/kprobes.c           |    2 +-
 arch/sparc/kernel/kprobes.c        |    2 +-
 arch/x86/include/asm/kprobes.h     |    1 -
 arch/x86/kernel/kprobes/core.c     |    2 +-
 include/linux/kprobes.h            |   18 +++++++++++++-----
 kernel/kprobes.c                   |    3 +--
 16 files changed, 29 insertions(+), 27 deletions(-)

diff --git a/arch/arc/kernel/kprobes.c b/arch/arc/kernel/kprobes.c
index 5f0415fc7328..3cee75c87f97 100644
--- a/arch/arc/kernel/kprobes.c
+++ b/arch/arc/kernel/kprobes.c
@@ -381,7 +381,7 @@ void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
 static int __kprobes trampoline_probe_handler(struct kprobe *p,
 					      struct pt_regs *regs)
 {
-	regs->ret = __kretprobe_trampoline_handler(regs, &kretprobe_trampoline, NULL);
+	regs->ret = __kretprobe_trampoline_handler(regs, NULL);
 
 	/* By returning a non zero value, we are telling the kprobe handler
 	 * that we don't want the post_handler to run
diff --git a/arch/arm/probes/kprobes/core.c b/arch/arm/probes/kprobes/core.c
index a59e38de4a03..08098ed6f035 100644
--- a/arch/arm/probes/kprobes/core.c
+++ b/arch/arm/probes/kprobes/core.c
@@ -392,8 +392,7 @@ void __naked __kprobes kretprobe_trampoline(void)
 /* Called from kretprobe_trampoline */
 static __used __kprobes void *trampoline_handler(struct pt_regs *regs)
 {
-	return (void *)kretprobe_trampoline_handler(regs, &kretprobe_trampoline,
-						    (void *)regs->ARM_fp);
+	return (void *)kretprobe_trampoline_handler(regs, (void *)regs->ARM_fp);
 }
 
 void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
diff --git a/arch/arm64/kernel/probes/kprobes.c b/arch/arm64/kernel/probes/kprobes.c
index ce429cbacd35..f627a12984a8 100644
--- a/arch/arm64/kernel/probes/kprobes.c
+++ b/arch/arm64/kernel/probes/kprobes.c
@@ -401,8 +401,7 @@ int __init arch_populate_kprobe_blacklist(void)
 
 void __kprobes __used *trampoline_probe_handler(struct pt_regs *regs)
 {
-	return (void *)kretprobe_trampoline_handler(regs, &kretprobe_trampoline,
-					(void *)kernel_stack_pointer(regs));
+	return (void *)kretprobe_trampoline_handler(regs, (void *)kernel_stack_pointer(regs));
 }
 
 void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
diff --git a/arch/csky/kernel/probes/kprobes.c b/arch/csky/kernel/probes/kprobes.c
index 632407bf45d5..784c5aba7f66 100644
--- a/arch/csky/kernel/probes/kprobes.c
+++ b/arch/csky/kernel/probes/kprobes.c
@@ -386,7 +386,7 @@ int __init arch_populate_kprobe_blacklist(void)
 
 void __kprobes __used *trampoline_probe_handler(struct pt_regs *regs)
 {
-	return (void *)kretprobe_trampoline_handler(regs, &kretprobe_trampoline, NULL);
+	return (void *)kretprobe_trampoline_handler(regs, NULL);
 }
 
 void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
diff --git a/arch/ia64/kernel/kprobes.c b/arch/ia64/kernel/kprobes.c
index 0f8573bbf520..44c84c20b626 100644
--- a/arch/ia64/kernel/kprobes.c
+++ b/arch/ia64/kernel/kprobes.c
@@ -392,14 +392,13 @@ static void __kprobes set_current_kprobe(struct kprobe *p,
 	__this_cpu_write(current_kprobe, p);
 }
 
-static void kretprobe_trampoline(void)
+void kretprobe_trampoline(void)
 {
 }
 
 int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
 {
-	regs->cr_iip = __kretprobe_trampoline_handler(regs,
-		dereference_function_descriptor(kretprobe_trampoline), NULL);
+	regs->cr_iip = __kretprobe_trampoline_handler(regs, NULL);
 	/*
 	 * By returning a non-zero value, we are telling
 	 * kprobe_handler() that we don't want the post_handler
diff --git a/arch/mips/kernel/kprobes.c b/arch/mips/kernel/kprobes.c
index b0934a0d7aed..b33bd2498651 100644
--- a/arch/mips/kernel/kprobes.c
+++ b/arch/mips/kernel/kprobes.c
@@ -485,8 +485,7 @@ void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
 static int __kprobes trampoline_probe_handler(struct kprobe *p,
 						struct pt_regs *regs)
 {
-	instruction_pointer(regs) = __kretprobe_trampoline_handler(regs,
-						kretprobe_trampoline, NULL);
+	instruction_pointer(regs) = __kretprobe_trampoline_handler(regs, NULL);
 	/*
 	 * By returning a non-zero value, we are telling
 	 * kprobe_handler() that we don't want the post_handler
diff --git a/arch/parisc/kernel/kprobes.c b/arch/parisc/kernel/kprobes.c
index 6d21a515eea5..4a35ac6e2ca2 100644
--- a/arch/parisc/kernel/kprobes.c
+++ b/arch/parisc/kernel/kprobes.c
@@ -175,7 +175,7 @@ int __kprobes parisc_kprobe_ss_handler(struct pt_regs *regs)
 	return 1;
 }
 
-static inline void kretprobe_trampoline(void)
+void kretprobe_trampoline(void)
 {
 	asm volatile("nop");
 	asm volatile("nop");
@@ -193,7 +193,7 @@ static int __kprobes trampoline_probe_handler(struct kprobe *p,
 {
 	unsigned long orig_ret_address;
 
-	orig_ret_address = __kretprobe_trampoline_handler(regs, trampoline_p.addr, NULL);
+	orig_ret_address = __kretprobe_trampoline_handler(regs, NULL);
 	instruction_pointer_set(regs, orig_ret_address);
 
 	return 1;
diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c
index d422e297978b..43c77142a262 100644
--- a/arch/powerpc/kernel/kprobes.c
+++ b/arch/powerpc/kernel/kprobes.c
@@ -417,7 +417,7 @@ static int trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
 {
 	unsigned long orig_ret_address;
 
-	orig_ret_address = __kretprobe_trampoline_handler(regs, &kretprobe_trampoline, NULL);
+	orig_ret_address = __kretprobe_trampoline_handler(regs, NULL);
 	/*
 	 * We get here through one of two paths:
 	 * 1. by taking a trap -> kprobe_handler() -> here
diff --git a/arch/riscv/kernel/probes/kprobes.c b/arch/riscv/kernel/probes/kprobes.c
index cab6f874358e..62d477cf11da 100644
--- a/arch/riscv/kernel/probes/kprobes.c
+++ b/arch/riscv/kernel/probes/kprobes.c
@@ -347,7 +347,7 @@ int __init arch_populate_kprobe_blacklist(void)
 
 void __kprobes __used *trampoline_probe_handler(struct pt_regs *regs)
 {
-	return (void *)kretprobe_trampoline_handler(regs, &kretprobe_trampoline, NULL);
+	return (void *)kretprobe_trampoline_handler(regs, NULL);
 }
 
 void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
diff --git a/arch/s390/kernel/kprobes.c b/arch/s390/kernel/kprobes.c
index 952d44b0610b..5fa86e54f129 100644
--- a/arch/s390/kernel/kprobes.c
+++ b/arch/s390/kernel/kprobes.c
@@ -343,7 +343,7 @@ static void __used kretprobe_trampoline_holder(void)
  */
 static int trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
 {
-	regs->psw.addr = __kretprobe_trampoline_handler(regs, &kretprobe_trampoline, NULL);
+	regs->psw.addr = __kretprobe_trampoline_handler(regs, NULL);
 	/*
 	 * By returning a non-zero value, we are telling
 	 * kprobe_handler() that we don't want the post_handler
diff --git a/arch/sh/kernel/kprobes.c b/arch/sh/kernel/kprobes.c
index 1c7f358ef0be..8e76a35e6e33 100644
--- a/arch/sh/kernel/kprobes.c
+++ b/arch/sh/kernel/kprobes.c
@@ -303,7 +303,7 @@ static void __used kretprobe_trampoline_holder(void)
  */
 int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
 {
-	regs->pc = __kretprobe_trampoline_handler(regs, &kretprobe_trampoline, NULL);
+	regs->pc = __kretprobe_trampoline_handler(regs, NULL);
 
 	return 1;
 }
diff --git a/arch/sparc/kernel/kprobes.c b/arch/sparc/kernel/kprobes.c
index 4c05a4ee6a0e..401534236c2e 100644
--- a/arch/sparc/kernel/kprobes.c
+++ b/arch/sparc/kernel/kprobes.c
@@ -451,7 +451,7 @@ static int __kprobes trampoline_probe_handler(struct kprobe *p,
 {
 	unsigned long orig_ret_address = 0;
 
-	orig_ret_address = __kretprobe_trampoline_handler(regs, &kretprobe_trampoline, NULL);
+	orig_ret_address = __kretprobe_trampoline_handler(regs, NULL);
 	regs->tpc = orig_ret_address;
 	regs->tnpc = orig_ret_address + 4;
 
diff --git a/arch/x86/include/asm/kprobes.h b/arch/x86/include/asm/kprobes.h
index bd7f5886a789..71ea2eab43d5 100644
--- a/arch/x86/include/asm/kprobes.h
+++ b/arch/x86/include/asm/kprobes.h
@@ -49,7 +49,6 @@ extern __visible kprobe_opcode_t optprobe_template_end[];
 extern const int kretprobe_blacklist_size;
 
 void arch_remove_kprobe(struct kprobe *p);
-asmlinkage void kretprobe_trampoline(void);
 
 extern void arch_kprobe_override_function(struct pt_regs *regs);
 
diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c
index b6e046e4b289..0c59ef5971de 100644
--- a/arch/x86/kernel/kprobes/core.c
+++ b/arch/x86/kernel/kprobes/core.c
@@ -1064,7 +1064,7 @@ __used __visible void *trampoline_handler(struct pt_regs *regs)
 	regs->ip = (unsigned long)&kretprobe_trampoline;
 	regs->orig_ax = ~0UL;
 
-	return (void *)kretprobe_trampoline_handler(regs, &kretprobe_trampoline, &regs->sp);
+	return (void *)kretprobe_trampoline_handler(regs, &regs->sp);
 }
 NOKPROBE_SYMBOL(trampoline_handler);
 
diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h
index 2ed61fcbc89c..96f5df93e36e 100644
--- a/include/linux/kprobes.h
+++ b/include/linux/kprobes.h
@@ -188,15 +188,23 @@ extern void arch_prepare_kretprobe(struct kretprobe_instance *ri,
 				   struct pt_regs *regs);
 extern int arch_trampoline_kprobe(struct kprobe *p);
 
+void kretprobe_trampoline(void);
+/*
+ * Since some architecture uses structured function pointer,
+ * use dereference_function_descriptor() to get real function address.
+ */
+static nokprobe_inline void *kretprobe_trampoline_addr(void)
+{
+	return dereference_kernel_function_descriptor(kretprobe_trampoline);
+}
+
 /* If the trampoline handler called from a kprobe, use this version */
 unsigned long __kretprobe_trampoline_handler(struct pt_regs *regs,
-				void *trampoline_address,
-				void *frame_pointer);
+					     void *frame_pointer);
 
 static nokprobe_inline
 unsigned long kretprobe_trampoline_handler(struct pt_regs *regs,
-				void *trampoline_address,
-				void *frame_pointer)
+					   void *frame_pointer)
 {
 	unsigned long ret;
 	/*
@@ -205,7 +213,7 @@ unsigned long kretprobe_trampoline_handler(struct pt_regs *regs,
 	 * be running at this point.
 	 */
 	kprobe_busy_begin();
-	ret = __kretprobe_trampoline_handler(regs, trampoline_address, frame_pointer);
+	ret = __kretprobe_trampoline_handler(regs, frame_pointer);
 	kprobe_busy_end();
 
 	return ret;
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 550042d9a6ef..6ed755111eea 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -1864,7 +1864,6 @@ static struct notifier_block kprobe_exceptions_nb = {
 #ifdef CONFIG_KRETPROBES
 
 unsigned long __kretprobe_trampoline_handler(struct pt_regs *regs,
-					     void *trampoline_address,
 					     void *frame_pointer)
 {
 	kprobe_opcode_t *correct_ret_addr = NULL;
@@ -1879,7 +1878,7 @@ unsigned long __kretprobe_trampoline_handler(struct pt_regs *regs,
 
 		BUG_ON(ri->fp != frame_pointer);
 
-		if (ri->ret_addr != trampoline_address) {
+		if (ri->ret_addr != kretprobe_trampoline_addr()) {
 			correct_ret_addr = ri->ret_addr;
 			/*
 			 * This is the real return address. Any other


  parent reply	other threads:[~2021-09-14 14:41 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-14 14:38 [PATCH -tip v11 00/27] kprobes: Fix stacktrace with kretprobes on x86 Masami Hiramatsu
2021-09-14 14:38 ` [PATCH -tip v11 01/27] kprobes: Do not use local variable when creating debugfs file Masami Hiramatsu
2021-09-14 14:38 ` [PATCH -tip v11 02/27] kprobes: Use helper to parse boolean input from userspace Masami Hiramatsu
2021-09-14 14:38 ` [PATCH -tip v11 03/27] kprobe: Simplify prepare_kprobe() by dropping redundant version Masami Hiramatsu
2021-09-14 14:39 ` [PATCH -tip v11 04/27] csky: ftrace: Drop duplicate implementation of arch_check_ftrace_location() Masami Hiramatsu
2021-09-14 14:39 ` [PATCH -tip v11 05/27] kprobes: Make arch_check_ftrace_location static Masami Hiramatsu
2021-09-14 14:39 ` [PATCH -tip v11 06/27] kprobes: treewide: Cleanup the error messages for kprobes Masami Hiramatsu
2021-09-14 14:39 ` [PATCH -tip v11 07/27] kprobes: Fix coding style issues Masami Hiramatsu
2021-09-14 14:39 ` [PATCH -tip v11 08/27] kprobes: Use IS_ENABLED() instead of kprobes_built_in() Masami Hiramatsu
2021-09-14 14:39 ` [PATCH -tip v11 09/27] kprobes: Add assertions for required lock Masami Hiramatsu
2021-09-14 14:40 ` [PATCH -tip v11 10/27] kprobes: treewide: Use 'kprobe_opcode_t *' for the code address in get_optimized_kprobe() Masami Hiramatsu
2021-09-14 14:40 ` [PATCH -tip v11 11/27] kprobes: Use bool type for functions which returns boolean value Masami Hiramatsu
2021-09-14 14:40 ` [PATCH -tip v11 12/27] ia64: kprobes: Fix to pass correct trampoline address to the handler Masami Hiramatsu
2021-09-14 14:40 ` [PATCH -tip v11 13/27] kprobes: treewide: Replace arch_deref_entry_point() with dereference_symbol_descriptor() Masami Hiramatsu
2021-09-14 14:40 ` Masami Hiramatsu [this message]
2021-09-14 14:40 ` [PATCH -tip v11 15/27] kprobes: treewide: Make it harder to refer kretprobe_trampoline directly Masami Hiramatsu
2021-09-14 14:41 ` [PATCH -tip v11 16/27] kprobes: Add kretprobe_find_ret_addr() for searching return address Masami Hiramatsu
2021-09-14 14:41 ` [PATCH -tip v11 17/27] objtool: Add frame-pointer-specific function ignore Masami Hiramatsu
2021-09-14 14:41 ` [PATCH -tip v11 18/27] objtool: Ignore unwind hints for ignored functions Masami Hiramatsu
2021-09-14 14:41 ` [PATCH -tip v11 19/27] x86/kprobes: Add UNWIND_HINT_FUNC on kretprobe_trampoline() Masami Hiramatsu
2021-09-14 14:41 ` [PATCH -tip v11 20/27] ARC: Add instruction_pointer_set() API Masami Hiramatsu
2021-09-14 14:41 ` [PATCH -tip v11 21/27] ia64: " Masami Hiramatsu
2021-09-14 14:42 ` [PATCH -tip v11 22/27] arm: kprobes: Make space for instruction pointer on stack Masami Hiramatsu
2021-09-14 14:42 ` [PATCH -tip v11 23/27] kprobes: Enable stacktrace from pt_regs in kretprobe handler Masami Hiramatsu
2021-09-14 14:42 ` [PATCH -tip v11 24/27] x86/kprobes: Push a fake return address at kretprobe_trampoline Masami Hiramatsu
2021-09-14 14:42 ` [PATCH -tip v11 25/27] x86/unwind: Recover kretprobe trampoline entry Masami Hiramatsu
2021-09-14 14:42 ` [PATCH -tip v11 26/27] tracing: Show kretprobe unknown indicator only for kretprobe_trampoline Masami Hiramatsu
2021-09-14 14:42 ` [PATCH -tip v11 27/27] x86/kprobes: Fixup return address in generic trampoline handler Masami Hiramatsu
2021-09-14 22:55 ` [PATCH -tip v11 00/27] kprobes: Fix stacktrace with kretprobes on x86 Andrii Nakryiko
2021-09-29  2:24 ` Masami Hiramatsu
2021-09-30 18:17   ` Alexei Starovoitov
2021-09-30 19:34     ` Thomas Gleixner
2021-09-30 21:22       ` Steven Rostedt
2021-09-30 23:11         ` Thomas Gleixner
2021-09-30 23:27           ` Masami Hiramatsu
2021-09-30 23:37             ` Steven Rostedt
2021-10-01  0:35               ` Masami Hiramatsu
2021-09-30 23:54       ` Masami Hiramatsu

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