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-rw-r--r--arch/parisc/kernel/ptrace.c29
1 files changed, 21 insertions, 8 deletions
diff --git a/arch/parisc/kernel/ptrace.c b/arch/parisc/kernel/ptrace.c
index e02d7b4d2b69..0780c375fe2e 100644
--- a/arch/parisc/kernel/ptrace.c
+++ b/arch/parisc/kernel/ptrace.c
@@ -311,15 +311,29 @@ 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. */
@@ -343,7 +357,6 @@ 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