(COMPILE TESTED, needs an ack from Eric)
proc_pid_make_inode:
ei->pid = get_pid(task_pid(task));
I think this is not safe. get_pid() can be preempted after checking
"pid != NULL". Then the task exits, does detach_pid(), and RCU frees
the pid.
Signed-off-by: Oleg Nesterov <[email protected]>
--- rc6-mm1/include/linux/pid.h~1_tgp 2006-09-09 22:34:50.000000000 +0400
+++ rc6-mm1/include/linux/pid.h 2006-09-11 05:46:14.000000000 +0400
@@ -68,6 +68,8 @@ extern struct task_struct *FASTCALL(pid_
extern struct task_struct *FASTCALL(get_pid_task(struct pid *pid,
enum pid_type));
+extern struct pid *get_task_pid(struct task_struct *task, enum pid_type type);
+
/*
* attach_pid() and detach_pid() must be called with the tasklist_lock
* write-held.
--- rc6-mm1/kernel/pid.c~1_tgp 2006-09-09 22:34:50.000000000 +0400
+++ rc6-mm1/kernel/pid.c 2006-09-11 05:39:23.000000000 +0400
@@ -305,6 +305,15 @@ struct task_struct *find_task_by_pid_typ
EXPORT_SYMBOL(find_task_by_pid_type);
+struct pid *get_task_pid(struct task_struct *task, enum pid_type type)
+{
+ struct pid *pid;
+ rcu_read_lock();
+ pid = get_pid(task->pids[type].pid);
+ rcu_read_unlock();
+ return pid;
+}
+
struct task_struct *fastcall get_pid_task(struct pid *pid, enum pid_type type)
{
struct task_struct *result;
--- rc6-mm1/fs/proc/base.c~1_tgp 2006-09-09 22:34:49.000000000 +0400
+++ rc6-mm1/fs/proc/base.c 2006-09-11 05:56:19.000000000 +0400
@@ -958,7 +958,7 @@ static struct inode *proc_pid_make_inode
/*
* grab the reference to task.
*/
- ei->pid = get_pid(task_pid(task));
+ ei->pid = get_task_pid(task, PIDTYPE_PID);
if (!ei->pid)
goto out_unlock;
@@ -1665,7 +1665,7 @@ static struct dentry *proc_base_instanti
/*
* grab the reference to the task.
*/
- ei->pid = get_pid(task_pid(task));
+ ei->pid = get_task_pid(task, PIDTYPE_PID);
if (!ei->pid)
goto out_iput;
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
