linux-kernel - Re: [PATCH] sh: kprobes: remove unused variables in kprobe_exceptions

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Message-ID: <916e98179181eebbfbfc2548a40a800e8c703525.camel@physik.fu-berlin.de>
Date: Sat, 07 Jun 2025 15:10:14 +0200
From: John Paul Adrian Glaubitz <glaubitz@...sik.fu-berlin.de>
To: Mike Rapoport <rppt@...nel.org>
Cc: Mike Rapoport <rppt@...il.com>, Rich Felker <dalias@...c.org>, Yoshinori
 Sato <ysato@...rs.sourceforge.jp>, linux-kernel@...r.kernel.org,
 linux-sh@...r.kernel.org,  kernel test robot	 <lkp@...el.com>
Subject: Re: [PATCH] sh: kprobes: remove unused variables in
 kprobe_exceptions_notify()

Hi Mike,

On Sat, 2025-05-17 at 12:30 +0300, Mike Rapoport wrote:
> From: "Mike Rapoport (Microsoft)" <rppt@...nel.org>
> 
> kbuild reports the following warning:
> 
>    arch/sh/kernel/kprobes.c: In function 'kprobe_exceptions_notify':
> > > arch/sh/kernel/kprobes.c:412:24: warning: variable 'p' set but not used [-Wunused-but-set-variable]
>      412 |         struct kprobe *p = NULL;
>          |                        ^
> 
> The variable 'p' is indeed unused since the commit fa5a24b16f94
> ("sh/kprobes: Don't call the ->break_handler() in SH kprobes code")
> 
> Remove that variable along with 'kprobe_opcode_t *addr' which also
> becomes unused after 'p' is removed.
> 
> Reported-by: kernel test robot <lkp@...el.com>
> Closes: https://lore.kernel.org/oe-kbuild-all/202505151341.EuRFR22l-lkp@intel.com/
> Fixes: fa5a24b16f94 ("sh/kprobes: Don't call the ->break_handler() in SH kprobes code")
> Signed-off-by: Mike Rapoport (Microsoft) <rppt@...nel.org>
> ---
> 
> I don't know why the warning poped up only now, the code there didn't
> change for some time :/
> 
>  arch/sh/kernel/kprobes.c | 4 ----
>  1 file changed, 4 deletions(-)
> 
> diff --git a/arch/sh/kernel/kprobes.c b/arch/sh/kernel/kprobes.c
> index 49c4ffd782d6..a250fb1b9420 100644
> --- a/arch/sh/kernel/kprobes.c
> +++ b/arch/sh/kernel/kprobes.c
> @@ -404,13 +404,10 @@ int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
>  int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
>  				       unsigned long val, void *data)
>  {
> -	struct kprobe *p = NULL;
>  	struct die_args *args = (struct die_args *)data;
>  	int ret = NOTIFY_DONE;
> -	kprobe_opcode_t *addr = NULL;
>  	struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
>  
> -	addr = (kprobe_opcode_t *) (args->regs->pc);
>  	if (val == DIE_TRAP &&
>  	    args->trapnr == (BREAKPOINT_INSTRUCTION & 0xff)) {
>  		if (!kprobe_running()) {
> @@ -421,7 +418,6 @@ int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
>  				ret = NOTIFY_DONE;
>  			}
>  		} else {
> -			p = get_kprobe(addr);
>  			if ((kcb->kprobe_status == KPROBE_HIT_SS) ||
>  			    (kcb->kprobe_status == KPROBE_REENTER)) {
>  				if (post_kprobe_handler(args->regs))

Thanks for catching this! Looks good to me!

Reviewed-by: John Paul Adrian Glaubitz <glaubitz@...sik.fu-berlin.de>

Adrian

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