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authorLi Zefan <lizefan@huawei.com>2013-04-18 23:09:52 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-05-07 20:33:11 -0700
commitae37359690c7d3dad9504041c0c414e004c9a275 (patch)
tree4f26d4b7fe008a9a046d63ee34aa83f73395559a /kernel
parentd52008e48529bfb3ad9d223fb0a7d116baaef9c0 (diff)
cgroup: fix broken file xattrs
commit 712317ad97f41e738e1a19aa0a6392a78a84094e upstream. We should store file xattrs in struct cfent instead of struct cftype, because cftype is a type while cfent is object instance of cftype. For example each cgroup has a tasks file, and each tasks file is associated with a uniq cfent, but all those files share the same struct cftype. Alexey Kodanev reported a crash, which can be reproduced: # mount -t cgroup -o xattr /sys/fs/cgroup # mkdir /sys/fs/cgroup/test # setfattr -n trusted.value -v test_value /sys/fs/cgroup/tasks # rmdir /sys/fs/cgroup/test # umount /sys/fs/cgroup oops! In this case, simple_xattrs_free() will free the same struct simple_xattrs twice. tj: Dropped unused local variable @cft from cgroup_diput(). Reported-by: Alexey Kodanev <alexey.kodanev@oracle.com> Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/cgroup.c11
1 files changed, 6 insertions, 5 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 55fca47e13d..ba1f9776dd1 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -162,6 +162,9 @@ struct cfent {
struct list_head node;
struct dentry *dentry;
struct cftype *type;
+
+ /* file xattrs */
+ struct simple_xattrs xattrs;
};
/*
@@ -910,13 +913,12 @@ static void cgroup_diput(struct dentry *dentry, struct inode *inode)
} else {
struct cfent *cfe = __d_cfe(dentry);
struct cgroup *cgrp = dentry->d_parent->d_fsdata;
- struct cftype *cft = cfe->type;
WARN_ONCE(!list_empty(&cfe->node) &&
cgrp != &cgrp->root->top_cgroup,
"cfe still linked for %s\n", cfe->type->name);
+ simple_xattrs_free(&cfe->xattrs);
kfree(cfe);
- simple_xattrs_free(&cft->xattrs);
}
iput(inode);
}
@@ -2551,7 +2553,7 @@ static struct simple_xattrs *__d_xattrs(struct dentry *dentry)
if (S_ISDIR(dentry->d_inode->i_mode))
return &__d_cgrp(dentry)->xattrs;
else
- return &__d_cft(dentry)->xattrs;
+ return &__d_cfe(dentry)->xattrs;
}
static inline int xattr_enabled(struct dentry *dentry)
@@ -2727,8 +2729,6 @@ static int cgroup_add_file(struct cgroup *cgrp, struct cgroup_subsys *subsys,
umode_t mode;
char name[MAX_CGROUP_TYPE_NAMELEN + MAX_CFTYPE_NAME + 2] = { 0 };
- simple_xattrs_init(&cft->xattrs);
-
if (subsys && !test_bit(ROOT_NOPREFIX, &cgrp->root->flags)) {
strcpy(name, subsys->name);
strcat(name, ".");
@@ -2753,6 +2753,7 @@ static int cgroup_add_file(struct cgroup *cgrp, struct cgroup_subsys *subsys,
cfe->type = (void *)cft;
cfe->dentry = dentry;
dentry->d_fsdata = cfe;
+ simple_xattrs_init(&cfe->xattrs);
list_add_tail(&cfe->node, &parent->files);
cfe = NULL;
}