Re: [PATCH] proc: readdir race fix.

From: Eric W. Biederman
Date: Mon Sep 04 2006 - 22:53:13 EST


KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> writes:

> On Mon, 04 Sep 2006 17:13:10 -0600
> ebiederm@xxxxxxxxxxxx (Eric W. Biederman) wrote:
> Hi, Hit OOM-Killer, because of memory leak of task struct.
>
> patch is attached.
> -Kame
>
> task struct should be put always.

Good catch. I actually have a pending cleanup that works better if the
task struct is held across the filldir so the incremental patch should look like:

I also noticed a benign typo in TGID_OFFSET (1 subtract one that I shouldn't)

Complete patch in just a moment.

Eric

diff --git a/fs/proc/base.c b/fs/proc/base.c
index b7650b9..03f6680 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -2186,7 +2186,7 @@ int proc_pid_readdir(struct file * filp,
tgid = filp->f_pos - TGID_OFFSET;
for (task = next_tgid(tgid);
task;
- task = next_tgid(tgid + 1)) {
+ put_task_struct(task), task = next_tgid(tgid + 1)) {
int len;
ino_t ino;
tgid = task->pid;

-
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