Re: [patch 14/18] entry: Make return type of syscall_trace_enter() bool

On Tue, Jul 07, 2026 at 09:06:53PM +0200, Thomas Gleixner wrote:
> This prepares for changing the return types of
> syscall_enter_from_user_mode[_work]() to bool, which in turn separates the
> decision of invoking the syscall from the syscall number, which might have
> been changed in the call by ptrace, seccomp, tracing.
> 
> Signed-off-by: Thomas Gleixner <[email protected]>
> ---
>  include/linux/entry-common.h |   28 +++++++++++++++-------------
>  1 file changed, 15 insertions(+), 13 deletions(-)
> 
> --- a/include/linux/entry-common.h
> +++ b/include/linux/entry-common.h
> @@ -71,8 +71,8 @@ static inline void syscall_enter_audit(s
>  	}
>  }
>  
> -static __always_inline long syscall_trace_enter(struct pt_regs *regs, unsigned long work,
> -						long syscall)
> +static __always_inline bool syscall_trace_enter(struct pt_regs *regs, unsigned long work,
> +						long *syscall)
>  {
>  	/*
>  	 * Handle Syscall User Dispatch.  This must comes first, since
> @@ -81,7 +81,7 @@ static __always_inline long syscall_trac
>  	 */
>  	if (work & SYSCALL_WORK_SYSCALL_USER_DISPATCH) {
>  		if (syscall_user_dispatch(regs))
> -			return -1L;
> +			return false;
>  	}
>  
>  	/*
> @@ -90,32 +90,32 @@ static __always_inline long syscall_trac
>  	 * through hrtimer_interrupt().
>  	 */
>  	if (work & SYSCALL_WORK_SYSCALL_RSEQ_SLICE)
> -		rseq_syscall_enter_work(syscall);
> +		rseq_syscall_enter_work(*syscall);
>  
>  	/* Handle ptrace */
>  	if (work & (SYSCALL_WORK_SYSCALL_TRACE | SYSCALL_WORK_SYSCALL_EMU)) {
>  		if (!arch_ptrace_report_syscall_permit_entry(regs) ||
>  		    (work & SYSCALL_WORK_SYSCALL_EMU))
> -			return -1L;
> +			return false;
>  	}
>  
>  	/* Do seccomp after ptrace, to catch any tracer changes. */
>  	if (work & SYSCALL_WORK_SECCOMP) {
>  		if (!__seccomp_permit_syscall())
> -			return -1L;
> +			return false;
>  	}
>  
>  	/* Either of the above might have changed the syscall number */
> -	syscall = syscall_get_nr(current, regs);
> +	*syscall = syscall_get_nr(current, regs);
>  
>  	if (unlikely(work & SYSCALL_WORK_SYSCALL_TRACEPOINT)) {
> -		if (!trace_syscall_enter(regs, &syscall))
> -			return -1L;
> +		if (!trace_syscall_enter(regs, syscall))
> +			return false;
>  	}
>  
> -	syscall_enter_audit(regs, syscall);
> +	syscall_enter_audit(regs, *syscall);
>  
> -	return syscall;
> +	return true;
>  }
>  
>  /**
> @@ -145,8 +145,10 @@ static __always_inline long syscall_ente
>  {
>  	unsigned long work = READ_ONCE(current_thread_info()->syscall_work);
>  
> -	if (work & SYSCALL_WORK_ENTER)
> -		syscall = syscall_trace_enter(regs, work, syscall);
> +	if (work & SYSCALL_WORK_ENTER) {
> +		if (!syscall_trace_enter(regs, work, &syscall))
> +			return -1L;
> +	}
>  
>  	return syscall;
>  }
> 
Reviewed-by: Mukesh Kumar Chaurasiya (IBM) <[email protected]>