diff options
| -rw-r--r-- | lib/syscall.c | 15 |
1 files changed, 13 insertions, 2 deletions
diff --git a/lib/syscall.c b/lib/syscall.c index e30e03932480..63239e097b13 100644 --- a/lib/syscall.c +++ b/lib/syscall.c @@ -7,9 +7,19 @@ static int collect_syscall(struct task_struct *target, long *callno, unsigned long args[6], unsigned int maxargs, unsigned long *sp, unsigned long *pc) { - struct pt_regs *regs = task_pt_regs(target); - if (unlikely(!regs)) + struct pt_regs *regs; + + if (!try_get_task_stack(target)) { + /* Task has no stack, so the task isn't in a syscall. */ + *callno = -1; + return 0; + } + + regs = task_pt_regs(target); + if (unlikely(!regs)) { + put_task_stack(target); return -EAGAIN; + } *sp = user_stack_pointer(regs); *pc = instruction_pointer(regs); @@ -18,6 +28,7 @@ static int collect_syscall(struct task_struct *target, long *callno, if (*callno != -1L && maxargs > 0) syscall_get_arguments(target, regs, 0, maxargs, args); + put_task_stack(target); return 0; } |