Commit 5861bbfc authored Aug 07, 2008 by Roland McGrath

tracehook: fix CLONE_PTRACE



In the change in commit 09a05394, I
overlooked two nits in the logic and this broke using CLONE_PTRACE
when PTRACE_O_TRACE* are not being used.

A parent that is itself traced at all but not using PTRACE_O_TRACE*,
using CLONE_PTRACE would have its new child fail to be traced.

A parent that is not itself traced at all that uses CLONE_PTRACE
(which should be a no-op in this case) would confuse the bookkeeping
and lead to a crash at exit time.

This restores the missing checks and fixes both failure modes.

Reported-by: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Roland McGrath <roland@redhat.com>

parent 685d87f7

include/linux/ptrace.h

+1 −1

Original line number	Diff line number	Diff line
		@@ -172,7 +172,7 @@ static inline void ptrace_init_task(struct task_struct *child, bool ptrace)
		child->ptrace = 0;
		if (unlikely(ptrace)) {
		child->ptrace = current->ptrace;
		__ptrace_link(child, current->parent);
		ptrace_link(child, current->parent);
		}
		}

include/linux/tracehook.h

+1 −1

Original line number	Diff line number	Diff line
		@@ -280,7 +280,7 @@ static inline void tracehook_report_clone(int trace, struct pt_regs *regs,
		unsigned long clone_flags,
		pid_t pid, struct task_struct *child)
		{
		if (unlikely(trace)) {
		if (unlikely(trace) \|\| unlikely(clone_flags & CLONE_PTRACE)) {
		/*
		* The child starts up with an immediate SIGSTOP.
		*/