diff mbox series

[-tip,v7,03/13] kprobes: treewide: Remove trampoline_address from kretprobe_trampoline_handler()

Message ID 162209757191.436794.12654958417415894884.stgit@devnote2 (mailing list archive)
State Not Applicable
Headers show
Series kprobes: Fix stacktrace with kretprobes on x86 | expand

Checks

Context Check Description
netdev/tree_selection success Not a local patch

Commit Message

Masami Hiramatsu (Google) May 27, 2021, 6:39 a.m. UTC 
Remove trampoline_address from kretprobe_trampoline_handler().
Instead of passing the address, kretprobe_trampoline_handler()
can use new kretprobe_trampoline_addr().

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Tested-by: Andrii Nakryik <andrii@kernel.org>
---
 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(-)

Comments

Naveen N. Rao June 14, 2021, 3:46 p.m. UTC | #1 
Hi Masami,

Masami Hiramatsu wrote:
> Remove trampoline_address from kretprobe_trampoline_handler().
> Instead of passing the address, kretprobe_trampoline_handler()
> can use new kretprobe_trampoline_addr().
> 
> Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
> Tested-by: Andrii Nakryik <andrii@kernel.org>
> ---
>  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(-)
> 

<snip>

> diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h
> index d65c041b5c22..65dadd4238a2 100644
> --- a/include/linux/kprobes.h
> +++ b/include/linux/kprobes.h
> @@ -205,15 +205,23 @@ 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_function_descriptor(kretprobe_trampoline);

I'm afraid this won't work correctly. For kernel functions, please use 
dereference_kernel_function_descriptor() which checks if the function 
has a descriptor before dereferencing it.


Thanks,
Naveen
Masami Hiramatsu (Google) June 15, 2021, 12:06 a.m. UTC | #2 
On Mon, 14 Jun 2021 21:16:26 +0530
"Naveen N. Rao" <naveen.n.rao@linux.ibm.com> wrote:

> Hi Masami,
> 
> Masami Hiramatsu wrote:
> > Remove trampoline_address from kretprobe_trampoline_handler().
> > Instead of passing the address, kretprobe_trampoline_handler()
> > can use new kretprobe_trampoline_addr().
> > 
> > Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
> > Tested-by: Andrii Nakryik <andrii@kernel.org>
> > ---
> >  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(-)
> > 
> 
> <snip>
> 
> > diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h
> > index d65c041b5c22..65dadd4238a2 100644
> > --- a/include/linux/kprobes.h
> > +++ b/include/linux/kprobes.h
> > @@ -205,15 +205,23 @@ 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_function_descriptor(kretprobe_trampoline);
> 
> I'm afraid this won't work correctly. For kernel functions, please use 
> dereference_kernel_function_descriptor() which checks if the function 
> has a descriptor before dereferencing it.

Oops, there is *kernel_function* version, I didn't notice that.
Thank you for reviewing! I'll fix that.

> 
> 
> Thanks,
> Naveen
>
diff mbox series

Patch

diff --git a/arch/arc/kernel/kprobes.c b/arch/arc/kernel/kprobes.c
index cabef45f11df..3ae01bb5820c 100644
--- a/arch/arc/kernel/kprobes.c
+++ b/arch/arc/kernel/kprobes.c
@@ -397,7 +397,7 @@  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 a9653117ca0d..1782b41df095 100644
--- a/arch/arm/probes/kprobes/core.c
+++ b/arch/arm/probes/kprobes/core.c
@@ -413,8 +413,7 @@  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 d607c9912025..813794f5636e 100644
--- a/arch/arm64/kernel/probes/kprobes.c
+++ b/arch/arm64/kernel/probes/kprobes.c
@@ -413,8 +413,7 @@  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 589f090f48b9..cc589bc11904 100644
--- a/arch/csky/kernel/probes/kprobes.c
+++ b/arch/csky/kernel/probes/kprobes.c
@@ -404,7 +404,7 @@  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 eaf3c734719b..0204953a06cf 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 54dfba8fa77c..001a2f07ef44 100644
--- a/arch/mips/kernel/kprobes.c
+++ b/arch/mips/kernel/kprobes.c
@@ -489,8 +489,7 @@  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 eb0460949e1b..dfd532c43525 100644
--- a/arch/powerpc/kernel/kprobes.c
+++ b/arch/powerpc/kernel/kprobes.c
@@ -399,7 +399,7 @@  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 10b965c34536..a1e4fce1604b 100644
--- a/arch/riscv/kernel/probes/kprobes.c
+++ b/arch/riscv/kernel/probes/kprobes.c
@@ -385,7 +385,7 @@  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 aae24dc75df6..b149e9169709 100644
--- a/arch/s390/kernel/kprobes.c
+++ b/arch/s390/kernel/kprobes.c
@@ -351,7 +351,7 @@  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 756100b01e84..48356e81836a 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 217c21a6986a..fa30f9dadff8 100644
--- a/arch/sparc/kernel/kprobes.c
+++ b/arch/sparc/kernel/kprobes.c
@@ -468,7 +468,7 @@  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 7c4d0736a998..d32b09ca3221 100644
--- a/arch/x86/kernel/kprobes/core.c
+++ b/arch/x86/kernel/kprobes/core.c
@@ -1070,7 +1070,7 @@  __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 d65c041b5c22..65dadd4238a2 100644
--- a/include/linux/kprobes.h
+++ b/include/linux/kprobes.h
@@ -205,15 +205,23 @@  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_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;
 	/*
@@ -222,7 +230,7 @@  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 b2bb572173d4..1d3087b59522 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -1859,7 +1859,6 @@  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;
@@ -1874,7 +1873,7 @@  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