[PATCH v9 03/16] arm64/ptrace: Return early for ptrace_report_syscall_entry() error

[Jinjie Ruan]

The generic entry abort the syscall_trace_enter() sequence if
ptrace_report_syscall_entry() errors out, but arm64 not.

As the ptrace_report_syscall_entry() comment said, the calling arch code
should abort the system call and must prevent normal entry so no system
call is made if ptrace_report_syscall_entry() return nonzero.

In preparation for moving arm64 over to the generic entry code,
return early if ptrace_report_syscall_entry() encounters an error.

Signed-off-by: Jinjie Ruan <ruanjin...@huawei.com>
---
 arch/arm64/kernel/ptrace.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c
index 4532e9831856..3926ce6aa268 100644
--- a/arch/arm64/kernel/ptrace.c
+++ b/arch/arm64/kernel/ptrace.c
@@ -2346,15 +2346,18 @@ static __always_inline unsigned long 
ptrace_save_reg(struct pt_regs *regs,
        return saved_reg;
 }
 
-static void report_syscall_entry(struct pt_regs *regs)
+static int report_syscall_entry(struct pt_regs *regs)
 {
        unsigned long saved_reg;
-       int regno;
+       int regno, ret;
 
        saved_reg = ptrace_save_reg(regs, PTRACE_SYSCALL_ENTER, &regno);
-       if (ptrace_report_syscall_entry(regs))
+       ret = ptrace_report_syscall_entry(regs);
+       if (ret)
                forget_syscall(regs);
        regs->regs[regno] = saved_reg;
+
+       return ret;
 }
 
 static void report_syscall_exit(struct pt_regs *regs)
@@ -2381,10 +2384,11 @@ static void report_syscall_exit(struct pt_regs *regs)
 int syscall_trace_enter(struct pt_regs *regs)
 {
        unsigned long flags = read_thread_flags();
+       int ret;
 
        if (flags & (_TIF_SYSCALL_EMU | _TIF_SYSCALL_TRACE)) {
-               report_syscall_entry(regs);
-               if (flags & _TIF_SYSCALL_EMU)
+               ret = report_syscall_entry(regs);
+               if (ret || (flags & _TIF_SYSCALL_EMU))
                        return NO_SYSCALL;
        }
 
-- 
2.34.1