Re: [PATCH 08/13] openrisc: pass all six syscall args to audit_syscall_entry()

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 2 potential issue(s) to consider:

New issues:
- [Low] The patch series breaks git bisectability by changing a core function signature before updating all architecture callers.

Pre-existing issues:
- [High] The return value of `do_syscall_trace_enter()` is ignored, breaking ptrace syscall abortion (e.g., PTRACE_SYSEMU).
--

--- Patch [8]: [PATCH 08/13] openrisc: pass all six syscall args to audit_syscall_entry() ---
commit 9ca4bd79e1e00767e994486accfe2484de6f3a04
Author: Ricardo Robaina <rrobaina@redhat.com>

openrisc: pass all six syscall args to audit_syscall_entry()

Update the audit_syscall_entry() call to forward the 5th and 6th syscall
arguments (gpr[7], gpr[8]) now that the audit core logs all six.

> diff --git a/arch/openrisc/kernel/ptrace.c b/arch/openrisc/kernel/ptrace.c
> index 552489b24855c..197a616d6c65c 100644
> --- a/arch/openrisc/kernel/ptrace.c
> +++ b/arch/openrisc/kernel/ptrace.c
> @@ -302,7 +302,8 @@ asmlinkage long do_syscall_trace_enter(struct pt_regs *regs)
>  		ret = -1L;
>  
>  	audit_syscall_entry(regs->gpr[11], regs->gpr[3], regs->gpr[4],
> -			    regs->gpr[5], regs->gpr[6]);
> +			    regs->gpr[5], regs->gpr[6],
> +			    regs->gpr[7], regs->gpr[8]);

[Severity: Low]
Will this change cause a git bisectability regression if architecture
callers are updated in subsequent commits?

If the core function signature of audit_syscall_entry() was changed in a
previous commit, intermediate commits checked out between the core change
and this architecture update will fail to compile on OpenRISC with a
"too few arguments to function" error.

>  
>  	return ret ? : regs->gpr[11];
>  }

[Severity: High]
This isn't a bug introduced by this patch, but is the return value ignored
by the assembly caller, potentially breaking ptrace syscall abortion?

If tracing decides a syscall should not happen (e.g., via PTRACE_SYSEMU)
and ptrace_report_syscall_entry() returns non-zero, this function attempts
to abort the syscall by returning -1L in r11.

However, the caller in arch/openrisc/kernel/entry.S unconditionally
reloads the original syscall number into r11, discarding the return value:

arch/openrisc/kernel/entry.S:_syscall_trace_enter()
    ...
    l.jal   do_syscall_trace_enter
     l.addi r3,r1,0

    /* Restore arguments ... */
    l.lwz   r11,PT_GPR11(r1)
    ...

Can this allow the original syscall to execute regardless of the tracer's
abort request?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/cover.1786626275.git.rrobaina@redhat.com?part=8