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| author | Li Zefan <lizefan@huawei.com> | 2013-04-18 23:09:52 -0700 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2013-04-18 23:11:40 -0700 |
| commit | 712317ad97f41e738e1a19aa0a6392a78a84094e (patch) | |
| tree | 66988449eb8cca53e032eed6ddc1169f9296eeac /kernel/cgroup.c | |
| parent | e57d5cf2f894e3f2727f8cf74bed0bc81cae70c8 (diff) | |
| download | lwn-712317ad97f41e738e1a19aa0a6392a78a84094e.tar.gz lwn-712317ad97f41e738e1a19aa0a6392a78a84094e.zip | |
cgroup: fix broken file xattrs
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().
Cc: <stable@vger.kernel.org> # 3.8.x
Reported-by: Alexey Kodanev <alexey.kodanev@oracle.com>
Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'kernel/cgroup.c')
| -rw-r--r-- | kernel/cgroup.c | 11 |
1 files changed, 6 insertions, 5 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c index c16719e056ab..192d762ec1f4 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -117,6 +117,9 @@ struct cfent { struct list_head node; struct dentry *dentry; struct cftype *type; + + /* file xattrs */ + struct simple_xattrs xattrs; }; /* @@ -882,13 +885,12 @@ 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); } @@ -2501,7 +2503,7 @@ 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) @@ -2677,8 +2679,6 @@ 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 && !(cgrp->root->flags & CGRP_ROOT_NOPREFIX)) { strcpy(name, subsys->name); strcat(name, "."); @@ -2703,6 +2703,7 @@ 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; } |