Pavel Emelianov [EMAIL PROTECTED] wrote:
| We must pass the namespace pointer to the alloc_pid() to
| show what namespace to allocate the pid from and we should
| call this *after* the namespace is copied.
| 
| Essentially, the task->pid etc initialization is done after
| the alloc_pid().
| 
| To do so I move the alloc_pid() inside copy_process() and
| introduce an argument to the alloc_pid() function.
| 
| Signed-off-by: Pavel Emelianov <[EMAIL PROTECTED]>
| 
| ---
| 
|  include/linux/pid.h |    2 +-
|  kernel/fork.c       |   29 +++++++++++++++++------------
|  kernel/pid.c        |    2 +-
|  3 files changed, 19 insertions(+), 14 deletions(-)
| 
| --- ./include/linux/pid.h.ve9 2007-07-06 11:03:55.000000000 +0400
| +++ ./include/linux/pid.h     2007-07-06 11:03:55.000000000 +0400
| @@ -116,7 +116,7 @@ extern struct pid *FASTCALL(find_pid_ns(
|  extern struct pid *find_get_pid(int nr);
|  extern struct pid *find_ge_pid(int nr, struct pid_namespace *);
| 
| -extern struct pid *alloc_pid(void);
| +extern struct pid *alloc_pid(struct pid_namespace *ns);
|  extern void FASTCALL(free_pid(struct pid *pid));
| 
|  /*
| --- ./kernel/fork.c.ve9       2007-07-06 11:03:55.000000000 +0400
| +++ ./kernel/fork.c   2007-07-06 11:04:07.000000000 +0400
| @@ -50,6 +50,7 @@
|  #include <linux/taskstats_kern.h>
|  #include <linux/random.h>
|  #include <linux/tty.h>
| +#include <linux/pid.h>
| 
|  #include <asm/pgtable.h>
|  #include <asm/pgalloc.h>
| @@ -1032,7 +1033,6 @@ static struct task_struct *copy_process(
|       p->did_exec = 0;
|       delayacct_tsk_init(p);  /* Must remain after dup_task_struct() */
|       copy_flags(clone_flags, p);
| -     p->pid = pid_nr(pid);
|       INIT_LIST_HEAD(&p->children);
|       INIT_LIST_HEAD(&p->sibling);
|       p->vfork_done = NULL;
| @@ -1107,10 +1107,6 @@ static struct task_struct *copy_process(
|       p->blocked_on = NULL; /* not blocked yet */
|  #endif
| 
| -     p->tgid = p->pid;
| -     if (clone_flags & CLONE_THREAD)
| -             p->tgid = current->tgid;
| -
|       if ((retval = security_task_alloc(p)))
|               goto bad_fork_cleanup_policy;
|       if ((retval = audit_alloc(p)))
| @@ -1132,9 +1128,14 @@ static struct task_struct *copy_process(
|               goto bad_fork_cleanup_mm;
|       if ((retval = copy_namespaces(clone_flags, p)))
|               goto bad_fork_cleanup_keys;
| +     if (likely(pid == NULL)) {
| +             pid = alloc_pid(p->nsproxy->pid_ns);
| +             if (pid == NULL)
| +                     goto bad_fork_cleanup_namespaces;
| +     }
|       retval = copy_thread(0, clone_flags, stack_start, stack_size, p, regs);
|       if (retval)
| -             goto bad_fork_cleanup_namespaces;
| +             goto bad_fork_cleanup_pid;
| 
|       p->set_child_tid = (clone_flags & CLONE_CHILD_SETTID) ? child_tidptr : 
NULL;
|       /*
| @@ -1255,6 +1256,11 @@ static struct task_struct *copy_process(
|               }
|       }
| 
| +     p->pid = pid_nr(pid);
| +     p->tgid = p->pid;
| +     if (clone_flags & CLONE_THREAD)
| +             p->tgid = current->tgid;
| +
|       if (likely(p->pid)) {
|               add_parent(p);
|               if (unlikely(p->ptrace & PT_PTRACED))
| @@ -1288,6 +1294,8 @@ static struct task_struct *copy_process(
|       proc_fork_connector(p);
|       return p;
| 
| +bad_fork_cleanup_pid:
| +     free_pid(pid);

If copy_process() was called from fork_idle(), pid would refer
to &init_struct_pid. Don't you need something like:

        if (pid == &init_struct_pid)
                return;

in free_pid() to not do anything in that case ?


|  bad_fork_cleanup_namespaces:
|       exit_task_namespaces(p);
|  bad_fork_cleanup_keys:
| @@ -1380,19 +1388,16 @@ long do_fork(unsigned long clone_flags,
|  {
|       struct task_struct *p;
|       int trace = 0;
| -     struct pid *pid = alloc_pid();
|       long nr;
| 
| -     if (!pid)
| -             return -EAGAIN;
| -     nr = pid->nr;
|       if (unlikely(current->ptrace)) {
|               trace = fork_traceflag (clone_flags);
|               if (trace)
|                       clone_flags |= CLONE_PTRACE;
|       }
| 
| -     p = copy_process(clone_flags, stack_start, regs, stack_size, 
parent_tidptr, child_tidptr, pid);
| +     p = copy_process(clone_flags, stack_start, regs, stack_size,
| +                     parent_tidptr, child_tidptr, NULL);
|       /*
|        * Do this prior waking up the new thread - the thread pointer
|        * might get invalid after that point, if the thread exits quickly.
| @@ -1418,6 +1423,7 @@ long do_fork(unsigned long clone_flags,
|               else
|                       p->state = TASK_STOPPED;
| 
| +             nr = pid_vnr(task_pid(p));
|               if (unlikely (trace)) {
|                       current->ptrace_message = nr;
|                       ptrace_notify ((trace << 8) | SIGTRAP);
| @@ -1433,7 +1439,6 @@ long do_fork(unsigned long clone_flags,
|                       }
|               }
|       } else {
| -             free_pid(pid);
|               nr = PTR_ERR(p);
|       }
|       return nr;
| --- ./kernel/pid.c.ve9        2007-07-06 11:03:55.000000000 +0400
| +++ ./kernel/pid.c    2007-07-06 11:03:55.000000000 +0400
| @@ -206,7 +206,7 @@ fastcall void free_pid(struct pid *pid)
|       call_rcu(&pid->rcu, delayed_put_pid);
|  }
| 
| -struct pid *alloc_pid(void)
| +struct pid *alloc_pid(struct pid_namespace *pid_ns)
|  {
|       struct pid *pid;
|       enum pid_type type;
-
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