This is a note to let you know that I've just added the patch titled
cpuset: fix cpuset_print_task_mems_allowed() vs rename() race
to the 3.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
cpuset-fix-cpuset_print_task_mems_allowed-vs-rename-race.patch
and it can be found in the queue-3.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 63f43f55c9bbc14f76b582644019b8a07dc8219a Mon Sep 17 00:00:00 2001
From: Li Zefan <lizefan@xxxxxxxxxx>
Date: Fri, 25 Jan 2013 16:08:01 +0800
Subject: cpuset: fix cpuset_print_task_mems_allowed() vs rename() race
From: Li Zefan <lizefan@xxxxxxxxxx>
commit 63f43f55c9bbc14f76b582644019b8a07dc8219a upstream.
rename() will change dentry->d_name. The result of this race can
be worse than seeing partially rewritten name, but we might access
a stale pointer because rename() will re-allocate memory to hold
a longer name.
It's safe in the protection of dentry->d_lock.
v2: check NULL dentry before acquiring dentry lock.
Signed-off-by: Li Zefan <lizefan@xxxxxxxxxx>
Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
kernel/cpuset.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -2479,8 +2479,16 @@ void cpuset_print_task_mems_allowed(stru
dentry = task_cs(tsk)->css.cgroup->dentry;
spin_lock(&cpuset_buffer_lock);
- snprintf(cpuset_name, CPUSET_NAME_LEN,
- dentry ? (const char *)dentry->d_name.name : "/");
+
+ if (!dentry) {
+ strcpy(cpuset_name, "/");
+ } else {
+ spin_lock(&dentry->d_lock);
+ strlcpy(cpuset_name, (const char *)dentry->d_name.name,
+ CPUSET_NAME_LEN);
+ spin_unlock(&dentry->d_lock);
+ }
+
nodelist_scnprintf(cpuset_nodelist, CPUSET_NODELIST_LEN,
tsk->mems_allowed);
printk(KERN_INFO "%s cpuset=%s mems_allowed=%s\n",
Patches currently in stable-queue which might be from lizefan@xxxxxxxxxx are
queue-3.4/cpuset-fix-cpuset_print_task_mems_allowed-vs-rename-race.patch
queue-3.4/cgroup-fix-exit-vs-rmdir-race.patch
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