Tony, please discard this patch. It can not fix completely. If ptrace caller wants to access vforked child process's user rbs, there will be problem. thanks bibo,mao bibo,mao wrote:
hi,
I encountered one problem when running ptrace test case, the
situation is this: traced process's syscall parameter needs to
be accessed, but for sys_clone system call with clone_flag
(CLONE_VFORK | CLONE_VM | SIGCHLD) parameter. this syscall's
parameter accessing result is wrong.
The reason is that with clone_flag(CLONE_VFORK | CLONE_VM | SIGCHLD),
cloned thread's mm point is the same, but tgid is different.
without this patch find_thread_for_addr will return cloned thread,
but not the thread which call sys_clone syscall.
thanks
bibo,mao
--- 2.6.19-rc5.org/arch/ia64/kernel/ptrace.c 2006-11-16 16:23:31.000000000 +0800
+++ 2.6.19-rc5/arch/ia64/kernel/ptrace.c 2006-11-16 16:25:07.000000000 +0800
@@ -607,7 +607,7 @@ find_thread_for_addr (struct task_struct
*/
list_for_each_safe(this, next, ¤t->children) {
p = list_entry(this, struct task_struct, sibling);
- if (p->mm != mm)
+ if (p->tgid != child->tgid)
continue;
if (thread_matches(p, addr)) {
child = p;
-
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