Re: [PATCH v2] samples/kprobes: Fix typo in handler_post()

[Joe Perches]

On Fri, 2021-05-14 at 16:10 +0800, Tiezhu Yang wrote:
> It should use post_handler instead of pre_handler in handler_post().
> 
> Fixes: e16c5dd5157e ("samples/kprobes: Add s390 case in kprobe example module")
> Signed-off-by: Tiezhu Yang <yangtiezhu@xxxxxxxxxxx>
> ---
> 
> v2: rebase on the latest mainline kernel
> 
>  samples/kprobes/kprobe_example.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/samples/kprobes/kprobe_example.c b/samples/kprobes/kprobe_example.c
> index c495664..602db3f 100644
> --- a/samples/kprobes/kprobe_example.c
> +++ b/samples/kprobes/kprobe_example.c
> @@ -89,7 +89,7 @@ static void __kprobes handler_post(struct kprobe *p, struct pt_regs *regs,
>  		p->symbol_name, p->addr, regs->status);
>  #endif
>  #ifdef CONFIG_S390
> -	pr_info("<%s> pre_handler: p->addr, 0x%p, flags = 0x%lx\n",
> +	pr_info("<%s> post_handler: p->addr, 0x%p, flags = 0x%lx\n",
>  		p->symbol_name, p->addr, regs->flags);
>  #endif
>  }

Perhaps better would be to use pr_fmt and remove all the
embedded pre/post strings.

This would change the style of the output through.

Also fix a defective format in handler_fault ending with
an 'n' that should be '\n'
---
 samples/kprobes/kprobe_example.c | 33 +++++++++++++++++----------------
 1 file changed, 17 insertions(+), 16 deletions(-)

diff --git a/samples/kprobes/kprobe_example.c b/samples/kprobes/kprobe_example.c
index c495664c0a9b..5f1eb8b53c11 100644
--- a/samples/kprobes/kprobe_example.c
+++ b/samples/kprobes/kprobe_example.c
@@ -10,6 +10,8 @@
  * whenever kernel_clone() is invoked to create a new process.
  */
 
+#define pr_fmt(fmt) "%s: " fmt, __func__
+
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/kprobes.h>
@@ -27,32 +29,31 @@ static struct kprobe kp = {
 static int __kprobes handler_pre(struct kprobe *p, struct pt_regs *regs)
 {
 #ifdef CONFIG_X86
-	pr_info("<%s> pre_handler: p->addr = 0x%p, ip = %lx, flags = 0x%lx\n",
+	pr_info("<%s> p->addr = 0x%p, ip = %lx, flags = 0x%lx\n",
 		p->symbol_name, p->addr, regs->ip, regs->flags);
 #endif
 #ifdef CONFIG_PPC
-	pr_info("<%s> pre_handler: p->addr = 0x%p, nip = 0x%lx, msr = 0x%lx\n",
+	pr_info("<%s> p->addr = 0x%p, nip = 0x%lx, msr = 0x%lx\n",
 		p->symbol_name, p->addr, regs->nip, regs->msr);
 #endif
 #ifdef CONFIG_MIPS
-	pr_info("<%s> pre_handler: p->addr = 0x%p, epc = 0x%lx, status = 0x%lx\n",
+	pr_info("<%s> p->addr = 0x%p, epc = 0x%lx, status = 0x%lx\n",
 		p->symbol_name, p->addr, regs->cp0_epc, regs->cp0_status);
 #endif
 #ifdef CONFIG_ARM64
-	pr_info("<%s> pre_handler: p->addr = 0x%p, pc = 0x%lx,"
-			" pstate = 0x%lx\n",
+	pr_info("<%s> p->addr = 0x%p, pc = 0x%lx, pstate = 0x%lx\n",
 		p->symbol_name, p->addr, (long)regs->pc, (long)regs->pstate);
 #endif
 #ifdef CONFIG_ARM
-	pr_info("<%s> pre_handler: p->addr = 0x%p, pc = 0x%lx, cpsr = 0x%lx\n",
+	pr_info("<%s> p->addr = 0x%p, pc = 0x%lx, cpsr = 0x%lx\n",
 		p->symbol_name, p->addr, (long)regs->ARM_pc, (long)regs->ARM_cpsr);
 #endif
 #ifdef CONFIG_RISCV
-	pr_info("<%s> pre_handler: p->addr = 0x%p, pc = 0x%lx, status = 0x%lx\n",
+	pr_info("<%s> p->addr = 0x%p, pc = 0x%lx, status = 0x%lx\n",
 		p->symbol_name, p->addr, regs->epc, regs->status);
 #endif
 #ifdef CONFIG_S390
-	pr_info("<%s> pre_handler: p->addr, 0x%p, ip = 0x%lx, flags = 0x%lx\n",
+	pr_info("<%s> p->addr, 0x%p, ip = 0x%lx, flags = 0x%lx\n",
 		p->symbol_name, p->addr, regs->psw.addr, regs->flags);
 #endif
 
@@ -65,31 +66,31 @@ static void __kprobes handler_post(struct kprobe *p, struct pt_regs *regs,
 				unsigned long flags)
 {
 #ifdef CONFIG_X86
-	pr_info("<%s> post_handler: p->addr = 0x%p, flags = 0x%lx\n",
+	pr_info("<%s> p->addr = 0x%p, flags = 0x%lx\n",
 		p->symbol_name, p->addr, regs->flags);
 #endif
 #ifdef CONFIG_PPC
-	pr_info("<%s> post_handler: p->addr = 0x%p, msr = 0x%lx\n",
+	pr_info("<%s> p->addr = 0x%p, msr = 0x%lx\n",
 		p->symbol_name, p->addr, regs->msr);
 #endif
 #ifdef CONFIG_MIPS
-	pr_info("<%s> post_handler: p->addr = 0x%p, status = 0x%lx\n",
+	pr_info("<%s> p->addr = 0x%p, status = 0x%lx\n",
 		p->symbol_name, p->addr, regs->cp0_status);
 #endif
 #ifdef CONFIG_ARM64
-	pr_info("<%s> post_handler: p->addr = 0x%p, pstate = 0x%lx\n",
+	pr_info("<%s> p->addr = 0x%p, pstate = 0x%lx\n",
 		p->symbol_name, p->addr, (long)regs->pstate);
 #endif
 #ifdef CONFIG_ARM
-	pr_info("<%s> post_handler: p->addr = 0x%p, cpsr = 0x%lx\n",
+	pr_info("<%s> p->addr = 0x%p, cpsr = 0x%lx\n",
 		p->symbol_name, p->addr, (long)regs->ARM_cpsr);
 #endif
 #ifdef CONFIG_RISCV
-	pr_info("<%s> post_handler: p->addr = 0x%p, status = 0x%lx\n",
+	pr_info("<%s> p->addr = 0x%p, status = 0x%lx\n",
 		p->symbol_name, p->addr, regs->status);
 #endif
 #ifdef CONFIG_S390
-	pr_info("<%s> pre_handler: p->addr, 0x%p, flags = 0x%lx\n",
+	pr_info("<%s> p->addr, 0x%p, flags = 0x%lx\n",
 		p->symbol_name, p->addr, regs->flags);
 #endif
 }
@@ -101,7 +102,7 @@ static void __kprobes handler_post(struct kprobe *p, struct pt_regs *regs,
  */
 static int handler_fault(struct kprobe *p, struct pt_regs *regs, int trapnr)
 {
-	pr_info("fault_handler: p->addr = 0x%p, trap #%dn", p->addr, trapnr);
+	pr_info("p->addr = 0x%p, trap #%d\n", p->addr, trapnr);
 	/* Return 0 because we don't handle the fault. */
 	return 0;
 }