diff options
| -rw-r--r-- | arch/parisc/kernel/ptrace.c | 29 |
1 files changed, 21 insertions, 8 deletions
diff --git a/arch/parisc/kernel/ptrace.c b/arch/parisc/kernel/ptrace.c index 2582df1c529b..0964c236e3e5 100644 --- a/arch/parisc/kernel/ptrace.c +++ b/arch/parisc/kernel/ptrace.c @@ -308,15 +308,29 @@ long compat_arch_ptrace(struct task_struct *child, compat_long_t request, long do_syscall_trace_enter(struct pt_regs *regs) { - if (test_thread_flag(TIF_SYSCALL_TRACE) && - tracehook_report_syscall_entry(regs)) { + if (test_thread_flag(TIF_SYSCALL_TRACE)) { + int rc = tracehook_report_syscall_entry(regs); + /* - * Tracing decided this syscall should not happen or the - * debugger stored an invalid system call number. Skip - * the system call and the system call restart handling. + * As tracesys_next does not set %r28 to -ENOSYS + * when %r20 is set to -1, initialize it here. */ - regs->gr[20] = -1UL; - goto out; + regs->gr[28] = -ENOSYS; + + if (rc) { + /* + * A nonzero return code from + * tracehook_report_syscall_entry() tells us + * to prevent the syscall execution. Skip + * the syscall call and the syscall restart handling. + * + * Note that the tracer may also just change + * regs->gr[20] to an invalid syscall number, + * that is handled by tracesys_next. + */ + regs->gr[20] = -1UL; + return -1; + } } /* Do the secure computing check after ptrace. */ @@ -340,7 +354,6 @@ long do_syscall_trace_enter(struct pt_regs *regs) regs->gr[24] & 0xffffffff, regs->gr[23] & 0xffffffff); -out: /* * Sign extend the syscall number to 64bit since it may have been * modified by a compat ptrace call |