Re: [PATCH] task_pid_nr_ns() breaks proc_pid_readdir()
Oleg Nesterov <[EMAIL PROTECTED]> writes: > On 11/19, Eric W. Biederman wrote: >> >> I think we can solve the immediate issues cleanly >> without it, and we are pretty much in bug fixing territory now. > > Yes sure. Besides, the "patch" I showed for illustration is not complete, > and it is not easy to solve the problems with exec(). > > Could you re-send your patch with changelog to Andrew? I agree, it is better > to pass a pointer than to add the horrible hack to proc_pid_readdir(). Definitely. I'm just testing now to make certain my code actually works. I have respun my patch to return a structure as I figured out how to do that cleanly. Eric - 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/
Re: [PATCH] task_pid_nr_ns() breaks proc_pid_readdir()
On 11/19, Eric W. Biederman wrote: > > I think we can solve the immediate issues cleanly > without it, and we are pretty much in bug fixing territory now. Yes sure. Besides, the "patch" I showed for illustration is not complete, and it is not easy to solve the problems with exec(). Could you re-send your patch with changelog to Andrew? I agree, it is better to pass a pointer than to add the horrible hack to proc_pid_readdir(). Oleg. - 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/
Re: [PATCH] task_pid_nr_ns() breaks proc_pid_readdir()
Oleg Nesterov <[EMAIL PROTECTED]> writes: > On 11/17, Eric W. Biederman wrote: >> >> Oleg Nesterov <[EMAIL PROTECTED]> writes: >> >> > Make sure that task_pid_nr_ns() returns !0 before updating tgid. Note that >> > next_tgid(tgid + 1) can find the same "struct pid" again, but we shouldn't >> > go into the endless loop because pid_task(PIDTYPE_PID) must return NULL in >> > this case, so next_tgid() can't return the same task. >> > >> Oleg I think I would rather update next_tgid to return the tgid (which >> removes the need to call task_pid_nr_ns). This keeps all of the task >> iteration logic together in next_tgid. > > Yes sure, I think your patch is also correct, please use it. > > > > Personally, I hate the functions which use pointers to return another value. > (yes, yes, I know, my taste is perverted). Why don't we return structure in > this case? We can even make a common helper struct, say, > > Of course, another option is to rewrite the kernle in perl, in that case > proc_pid_readdir() can just do > > (task, tgid) = next_tgid(); I wish that last syntax worked in C. That would make returning structures so much easier. From a compiler optimization standpoint returning structures is ever so much nicer. Seeing through pointers or references to optimize things is tricky. > > >> Although looking at this in more detail, I'm half wondering if >> proc_pid_make_inode() should take a struct pid instead of a task. > > Yes, I also thought about this. Needs more changes, and still not perfect. > > I am starting to think we need a more generic change. How about the patch > below? With this change the stable task_struct implies we have the stable > pids, this allows us to do a lot of cleanups. I don't see the huge pile of opportunities to clean up. But otherwise I am in favor of it. In the normal case it should only delay freeing of struct pid (and the corresponding namespace) by an rcu interval so it isn't a big deal. I suspect it will be a help with killing things like the global pids in task_struct. Regardless I'm going to pass on the keeping struct pid on the task struct until we free it and reference counting it there for the immediate present as I think we can solve the immediate issues cleanly without it, and we are pretty much in bug fixing territory now. Eric - 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/
Re: [PATCH] task_pid_nr_ns() breaks proc_pid_readdir()
Oleg Nesterov [EMAIL PROTECTED] writes: On 11/17, Eric W. Biederman wrote: Oleg Nesterov [EMAIL PROTECTED] writes: Make sure that task_pid_nr_ns() returns !0 before updating tgid. Note that next_tgid(tgid + 1) can find the same struct pid again, but we shouldn't go into the endless loop because pid_task(PIDTYPE_PID) must return NULL in this case, so next_tgid() can't return the same task. Oleg I think I would rather update next_tgid to return the tgid (which removes the need to call task_pid_nr_ns). This keeps all of the task iteration logic together in next_tgid. Yes sure, I think your patch is also correct, please use it. offtopic Personally, I hate the functions which use pointers to return another value. (yes, yes, I know, my taste is perverted). Why don't we return structure in this case? We can even make a common helper struct, say, Of course, another option is to rewrite the kernle in perl, in that case proc_pid_readdir() can just do (task, tgid) = next_tgid(); I wish that last syntax worked in C. That would make returning structures so much easier. From a compiler optimization standpoint returning structures is ever so much nicer. Seeing through pointers or references to optimize things is tricky. /offtopic Although looking at this in more detail, I'm half wondering if proc_pid_make_inode() should take a struct pid instead of a task. Yes, I also thought about this. Needs more changes, and still not perfect. I am starting to think we need a more generic change. How about the patch below? With this change the stable task_struct implies we have the stable pids, this allows us to do a lot of cleanups. I don't see the huge pile of opportunities to clean up. But otherwise I am in favor of it. In the normal case it should only delay freeing of struct pid (and the corresponding namespace) by an rcu interval so it isn't a big deal. I suspect it will be a help with killing things like the global pids in task_struct. Regardless I'm going to pass on the keeping struct pid on the task struct until we free it and reference counting it there for the immediate present as I think we can solve the immediate issues cleanly without it, and we are pretty much in bug fixing territory now. Eric - 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/
Re: [PATCH] task_pid_nr_ns() breaks proc_pid_readdir()
On 11/19, Eric W. Biederman wrote: I think we can solve the immediate issues cleanly without it, and we are pretty much in bug fixing territory now. Yes sure. Besides, the patch I showed for illustration is not complete, and it is not easy to solve the problems with exec(). Could you re-send your patch with changelog to Andrew? I agree, it is better to pass a pointer than to add the horrible hack to proc_pid_readdir(). Oleg. - 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/
Re: [PATCH] task_pid_nr_ns() breaks proc_pid_readdir()
Oleg Nesterov [EMAIL PROTECTED] writes: On 11/19, Eric W. Biederman wrote: I think we can solve the immediate issues cleanly without it, and we are pretty much in bug fixing territory now. Yes sure. Besides, the patch I showed for illustration is not complete, and it is not easy to solve the problems with exec(). Could you re-send your patch with changelog to Andrew? I agree, it is better to pass a pointer than to add the horrible hack to proc_pid_readdir(). Definitely. I'm just testing now to make certain my code actually works. I have respun my patch to return a structure as I figured out how to do that cleanly. Eric - 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/
Re: [PATCH] task_pid_nr_ns() breaks proc_pid_readdir()
On 11/17, Eric W. Biederman wrote:
>
> Oleg Nesterov <[EMAIL PROTECTED]> writes:
>
> > Make sure that task_pid_nr_ns() returns !0 before updating tgid. Note that
> > next_tgid(tgid + 1) can find the same "struct pid" again, but we shouldn't
> > go into the endless loop because pid_task(PIDTYPE_PID) must return NULL in
> > this case, so next_tgid() can't return the same task.
> >
> Oleg I think I would rather update next_tgid to return the tgid (which
> removes the need to call task_pid_nr_ns). This keeps all of the task
> iteration logic together in next_tgid.
Yes sure, I think your patch is also correct, please use it.
Personally, I hate the functions which use pointers to return another value.
(yes, yes, I know, my taste is perverted). Why don't we return structure in
this case? We can even make a common helper struct, say,
struct pair {
union {
long val1;
void *ptr1;
};
union {
long val2;
void *ptr2;
};
};
#define PAIR(x1, x2)(struct pair){{ . x1 }, { . x2 }}
Now, next_tgid() can do
return PAIR(ptr1 = task, val2 = tgid);
With -freg-struct-return the generated code is nice.
Of course, another option is to rewrite the kernle in perl, in that case
proc_pid_readdir() can just do
(task, tgid) = next_tgid();
> Although looking at this in more detail, I'm half wondering if
> proc_pid_make_inode() should take a struct pid instead of a task.
Yes, I also thought about this. Needs more changes, and still not perfect.
I am starting to think we need a more generic change. How about the patch
below? With this change the stable task_struct implies we have the stable
pids, this allows us to do a lot of cleanups.
Oleg.
--- kernel/pid.c2007-10-25 16:22:12.0 +0400
+++ - 2007-11-18 16:56:30.682555454 +0300
@@ -323,7 +323,7 @@ int fastcall attach_pid(struct task_stru
struct pid_link *link;
link = >pids[type];
- link->pid = pid;
+ link->pid = get_pid(pid);
hlist_add_head_rcu(>node, >tasks[type]);
return 0;
@@ -339,7 +339,6 @@ void fastcall detach_pid(struct task_str
pid = link->pid;
hlist_del_rcu(>node);
- link->pid = NULL;
for (tmp = PIDTYPE_MAX; --tmp >= 0; )
if (!hlist_empty(>tasks[tmp]))
@@ -348,6 +347,14 @@ void fastcall detach_pid(struct task_str
free_pid(pid);
}
+void task_put_pids(struct pid_link *pids)
+{
+ int type = PIDTYPE_MAX;
+
+ while (type--)
+ put_pid(pids[type].pid);
+}
+
/* transfer_pid is an optimization of attach_pid(new), detach_pid(old) */
void fastcall transfer_pid(struct task_struct *old, struct task_struct *new,
enum pid_type type)
--- kernel/fork.c 2007-11-09 12:57:31.0 +0300
+++ - 2007-11-18 16:57:34.037105563 +0300
@@ -121,6 +121,7 @@ void __put_task_struct(struct task_struc
WARN_ON(atomic_read(>usage));
WARN_ON(tsk == current);
+ task_put_pids(tsk->pids);
security_task_free(tsk);
free_uid(tsk->user);
put_group_info(tsk->group_info);
-
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Re: [PATCH] task_pid_nr_ns() breaks proc_pid_readdir()
On 11/17, Eric W. Biederman wrote:
Oleg Nesterov [EMAIL PROTECTED] writes:
Make sure that task_pid_nr_ns() returns !0 before updating tgid. Note that
next_tgid(tgid + 1) can find the same struct pid again, but we shouldn't
go into the endless loop because pid_task(PIDTYPE_PID) must return NULL in
this case, so next_tgid() can't return the same task.
Oleg I think I would rather update next_tgid to return the tgid (which
removes the need to call task_pid_nr_ns). This keeps all of the task
iteration logic together in next_tgid.
Yes sure, I think your patch is also correct, please use it.
offtopic
Personally, I hate the functions which use pointers to return another value.
(yes, yes, I know, my taste is perverted). Why don't we return structure in
this case? We can even make a common helper struct, say,
struct pair {
union {
long val1;
void *ptr1;
};
union {
long val2;
void *ptr2;
};
};
#define PAIR(x1, x2)(struct pair){{ . x1 }, { . x2 }}
Now, next_tgid() can do
return PAIR(ptr1 = task, val2 = tgid);
With -freg-struct-return the generated code is nice.
Of course, another option is to rewrite the kernle in perl, in that case
proc_pid_readdir() can just do
(task, tgid) = next_tgid();
/offtopic
Although looking at this in more detail, I'm half wondering if
proc_pid_make_inode() should take a struct pid instead of a task.
Yes, I also thought about this. Needs more changes, and still not perfect.
I am starting to think we need a more generic change. How about the patch
below? With this change the stable task_struct implies we have the stable
pids, this allows us to do a lot of cleanups.
Oleg.
--- kernel/pid.c2007-10-25 16:22:12.0 +0400
+++ - 2007-11-18 16:56:30.682555454 +0300
@@ -323,7 +323,7 @@ int fastcall attach_pid(struct task_stru
struct pid_link *link;
link = task-pids[type];
- link-pid = pid;
+ link-pid = get_pid(pid);
hlist_add_head_rcu(link-node, pid-tasks[type]);
return 0;
@@ -339,7 +339,6 @@ void fastcall detach_pid(struct task_str
pid = link-pid;
hlist_del_rcu(link-node);
- link-pid = NULL;
for (tmp = PIDTYPE_MAX; --tmp = 0; )
if (!hlist_empty(pid-tasks[tmp]))
@@ -348,6 +347,14 @@ void fastcall detach_pid(struct task_str
free_pid(pid);
}
+void task_put_pids(struct pid_link *pids)
+{
+ int type = PIDTYPE_MAX;
+
+ while (type--)
+ put_pid(pids[type].pid);
+}
+
/* transfer_pid is an optimization of attach_pid(new), detach_pid(old) */
void fastcall transfer_pid(struct task_struct *old, struct task_struct *new,
enum pid_type type)
--- kernel/fork.c 2007-11-09 12:57:31.0 +0300
+++ - 2007-11-18 16:57:34.037105563 +0300
@@ -121,6 +121,7 @@ void __put_task_struct(struct task_struc
WARN_ON(atomic_read(tsk-usage));
WARN_ON(tsk == current);
+ task_put_pids(tsk-pids);
security_task_free(tsk);
free_uid(tsk-user);
put_group_info(tsk-group_info);
-
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Re: [PATCH] task_pid_nr_ns() breaks proc_pid_readdir()
Oleg Nesterov <[EMAIL PROTECTED]> writes:
> proc_pid_readdir:
>
> for (...; ...; task = next_tgid(tgid + 1, ns)) {
> tgid = task_pid_nr_ns(task, ns);
> ... use tgid ...
>
> The first problem is that task_pid_nr_ns() can race with RCU and read the
> freed memory.
>
> However, rcu_read_lock() can't help. next_tgid() returns a pinned task_struct,
> but the task can be released (and it's pid detached) before task_pid_nr_ns()
> reads the pid_t value. In that case task_pid_nr_ns() returns 0 thus breaking
> the whole logic.
>
> Make sure that task_pid_nr_ns() returns !0 before updating tgid. Note that
> next_tgid(tgid + 1) can find the same "struct pid" again, but we shouldn't
> go into the endless loop because pid_task(PIDTYPE_PID) must return NULL in
> this case, so next_tgid() can't return the same task.
>
> Signed-off-by: Oleg Nesterov <[EMAIL PROTECTED]>
Oleg I think I would rather update next_tgid to return the tgid (which
removes the need to call task_pid_nr_ns). This keeps all of the task
iteration logic together in next_tgid.
Although looking at this in more detail, I'm half wondering if
proc_pid_make_inode() should take a struct pid instead of a task.
At first glance that looks like it might be a little simple and more
race free. Although it doesn't do any favors to:
> inode->i_gid = 0;
> if (task_dumpable(task)) {
> inode->i_uid = task->euid;
> inode->i_gid = task->egid;
> }
> security_task_to_inode(task, inode);
Anyway short of rewriting the world this is what updating next_tgid
looks like. Opinions?
Eric
diff --git a/fs/proc/base.c b/fs/proc/base.c
index a17c268..5d9328d 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -2411,7 +2411,7 @@ out:
* Find the first task with tgid >= tgid
*
*/
-static struct task_struct *next_tgid(unsigned int tgid,
+static struct task_struct *next_tgid(unsigned int *tgid,
struct pid_namespace *ns)
{
struct task_struct *task;
@@ -2420,9 +2420,9 @@ static struct task_struct *next_tgid(unsigned int tgid,
rcu_read_lock();
retry:
task = NULL;
- pid = find_ge_pid(tgid, ns);
+ pid = find_ge_pid(*tgid, ns);
if (pid) {
- tgid = pid_nr_ns(pid, ns) + 1;
+ *tgid = pid_nr_ns(pid, ns);
task = pid_task(pid, PIDTYPE_PID);
/* What we to know is if the pid we have find is the
* pid of a thread_group_leader. Testing for task
@@ -2436,8 +2436,10 @@ retry:
* found doesn't happen to be a thread group leader.
* As we don't care in the case of readdir.
*/
- if (!task || !has_group_leader_pid(task))
+ if (!task || !has_group_leader_pid(task)) {
+ *tgid += 1;
goto retry;
+ }
get_task_struct(task);
}
rcu_read_unlock();
@@ -2475,10 +2477,9 @@ int proc_pid_readdir(struct file * filp, void * dirent,
filldir_t filldir)
ns = filp->f_dentry->d_sb->s_fs_info;
tgid = filp->f_pos - TGID_OFFSET;
- for (task = next_tgid(tgid, ns);
+ for (task = next_tgid(, ns);
task;
-put_task_struct(task), task = next_tgid(tgid + 1, ns)) {
- tgid = task_pid_nr_ns(task, ns);
+put_task_struct(task), tgid += 1, task = next_tgid(, ns)) {
filp->f_pos = tgid + TGID_OFFSET;
if (proc_pid_fill_cache(filp, dirent, filldir, task, tgid) < 0)
{
put_task_struct(task);
-
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[PATCH] task_pid_nr_ns() breaks proc_pid_readdir()
proc_pid_readdir:
for (...; ...; task = next_tgid(tgid + 1, ns)) {
tgid = task_pid_nr_ns(task, ns);
... use tgid ...
The first problem is that task_pid_nr_ns() can race with RCU and read the
freed memory.
However, rcu_read_lock() can't help. next_tgid() returns a pinned task_struct,
but the task can be released (and it's pid detached) before task_pid_nr_ns()
reads the pid_t value. In that case task_pid_nr_ns() returns 0 thus breaking
the whole logic.
Make sure that task_pid_nr_ns() returns !0 before updating tgid. Note that
next_tgid(tgid + 1) can find the same "struct pid" again, but we shouldn't
go into the endless loop because pid_task(PIDTYPE_PID) must return NULL in
this case, so next_tgid() can't return the same task.
Signed-off-by: Oleg Nesterov <[EMAIL PROTECTED]>
--- 24/fs/proc/base.c~pprd 2007-10-25 16:22:11.0 +0400
+++ 24/fs/proc/base.c 2007-11-17 20:58:14.0 +0300
@@ -2481,7 +2481,15 @@ int proc_pid_readdir(struct file * filp,
for (task = next_tgid(tgid, ns);
task;
put_task_struct(task), task = next_tgid(tgid + 1, ns)) {
- tgid = task_pid_nr_ns(task, ns);
+ int nr;
+
+ rcu_read_lock();
+ nr = task_pid_nr_ns(task, ns);
+ rcu_read_unlock();
+ if (!nr)
+ continue;
+
+ tgid = nr;
filp->f_pos = tgid + TGID_OFFSET;
if (proc_pid_fill_cache(filp, dirent, filldir, task, tgid) < 0)
{
put_task_struct(task);
-
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[PATCH] task_pid_nr_ns() breaks proc_pid_readdir()
proc_pid_readdir:
for (...; ...; task = next_tgid(tgid + 1, ns)) {
tgid = task_pid_nr_ns(task, ns);
... use tgid ...
The first problem is that task_pid_nr_ns() can race with RCU and read the
freed memory.
However, rcu_read_lock() can't help. next_tgid() returns a pinned task_struct,
but the task can be released (and it's pid detached) before task_pid_nr_ns()
reads the pid_t value. In that case task_pid_nr_ns() returns 0 thus breaking
the whole logic.
Make sure that task_pid_nr_ns() returns !0 before updating tgid. Note that
next_tgid(tgid + 1) can find the same struct pid again, but we shouldn't
go into the endless loop because pid_task(PIDTYPE_PID) must return NULL in
this case, so next_tgid() can't return the same task.
Signed-off-by: Oleg Nesterov [EMAIL PROTECTED]
--- 24/fs/proc/base.c~pprd 2007-10-25 16:22:11.0 +0400
+++ 24/fs/proc/base.c 2007-11-17 20:58:14.0 +0300
@@ -2481,7 +2481,15 @@ int proc_pid_readdir(struct file * filp,
for (task = next_tgid(tgid, ns);
task;
put_task_struct(task), task = next_tgid(tgid + 1, ns)) {
- tgid = task_pid_nr_ns(task, ns);
+ int nr;
+
+ rcu_read_lock();
+ nr = task_pid_nr_ns(task, ns);
+ rcu_read_unlock();
+ if (!nr)
+ continue;
+
+ tgid = nr;
filp-f_pos = tgid + TGID_OFFSET;
if (proc_pid_fill_cache(filp, dirent, filldir, task, tgid) 0)
{
put_task_struct(task);
-
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Re: [PATCH] task_pid_nr_ns() breaks proc_pid_readdir()
Oleg Nesterov [EMAIL PROTECTED] writes:
proc_pid_readdir:
for (...; ...; task = next_tgid(tgid + 1, ns)) {
tgid = task_pid_nr_ns(task, ns);
... use tgid ...
The first problem is that task_pid_nr_ns() can race with RCU and read the
freed memory.
However, rcu_read_lock() can't help. next_tgid() returns a pinned task_struct,
but the task can be released (and it's pid detached) before task_pid_nr_ns()
reads the pid_t value. In that case task_pid_nr_ns() returns 0 thus breaking
the whole logic.
Make sure that task_pid_nr_ns() returns !0 before updating tgid. Note that
next_tgid(tgid + 1) can find the same struct pid again, but we shouldn't
go into the endless loop because pid_task(PIDTYPE_PID) must return NULL in
this case, so next_tgid() can't return the same task.
Signed-off-by: Oleg Nesterov [EMAIL PROTECTED]
Oleg I think I would rather update next_tgid to return the tgid (which
removes the need to call task_pid_nr_ns). This keeps all of the task
iteration logic together in next_tgid.
Although looking at this in more detail, I'm half wondering if
proc_pid_make_inode() should take a struct pid instead of a task.
At first glance that looks like it might be a little simple and more
race free. Although it doesn't do any favors to:
inode-i_gid = 0;
if (task_dumpable(task)) {
inode-i_uid = task-euid;
inode-i_gid = task-egid;
}
security_task_to_inode(task, inode);
Anyway short of rewriting the world this is what updating next_tgid
looks like. Opinions?
Eric
diff --git a/fs/proc/base.c b/fs/proc/base.c
index a17c268..5d9328d 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -2411,7 +2411,7 @@ out:
* Find the first task with tgid = tgid
*
*/
-static struct task_struct *next_tgid(unsigned int tgid,
+static struct task_struct *next_tgid(unsigned int *tgid,
struct pid_namespace *ns)
{
struct task_struct *task;
@@ -2420,9 +2420,9 @@ static struct task_struct *next_tgid(unsigned int tgid,
rcu_read_lock();
retry:
task = NULL;
- pid = find_ge_pid(tgid, ns);
+ pid = find_ge_pid(*tgid, ns);
if (pid) {
- tgid = pid_nr_ns(pid, ns) + 1;
+ *tgid = pid_nr_ns(pid, ns);
task = pid_task(pid, PIDTYPE_PID);
/* What we to know is if the pid we have find is the
* pid of a thread_group_leader. Testing for task
@@ -2436,8 +2436,10 @@ retry:
* found doesn't happen to be a thread group leader.
* As we don't care in the case of readdir.
*/
- if (!task || !has_group_leader_pid(task))
+ if (!task || !has_group_leader_pid(task)) {
+ *tgid += 1;
goto retry;
+ }
get_task_struct(task);
}
rcu_read_unlock();
@@ -2475,10 +2477,9 @@ int proc_pid_readdir(struct file * filp, void * dirent,
filldir_t filldir)
ns = filp-f_dentry-d_sb-s_fs_info;
tgid = filp-f_pos - TGID_OFFSET;
- for (task = next_tgid(tgid, ns);
+ for (task = next_tgid(tgid, ns);
task;
-put_task_struct(task), task = next_tgid(tgid + 1, ns)) {
- tgid = task_pid_nr_ns(task, ns);
+put_task_struct(task), tgid += 1, task = next_tgid(tgid, ns)) {
filp-f_pos = tgid + TGID_OFFSET;
if (proc_pid_fill_cache(filp, dirent, filldir, task, tgid) 0)
{
put_task_struct(task);
-
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