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authorZhihao Cheng <chengzhihao1@huawei.com>2021-12-27 11:22:37 +0800
committerRichard Weinberger <richard@nod.at>2022-01-10 22:01:04 +0100
commit60eb3b9c9f11206996f57cb89521824304b305ad (patch)
treeef38c448117a87ffbc5de828cf4c194d79caaf25 /fs/ubifs
parent278d9a243635f26c05ad95dcf9c5a593b9e04dc6 (diff)
ubifs: Fix 'ui->dirty' race between do_tmpfile() and writeback work
'ui->dirty' is not protected by 'ui_mutex' in function do_tmpfile() which may race with ubifs_write_inode[wb_workfn] to access/update 'ui->dirty', finally dirty space is released twice. open(O_TMPFILE) wb_workfn do_tmpfile ubifs_budget_space(ino_req = { .dirtied_ino = 1}) d_tmpfile // mark inode(tmpfile) dirty ubifs_jnl_update // without holding tmpfile's ui_mutex mark_inode_clean(ui) if (ui->dirty) ubifs_release_dirty_inode_budget(ui) // release first time ubifs_write_inode mutex_lock(&ui->ui_mutex) ubifs_release_dirty_inode_budget(ui) // release second time mutex_unlock(&ui->ui_mutex) ui->dirty = 0 Run generic/476 can reproduce following message easily (See reproducer in [Link]): UBIFS error (ubi0:0 pid 2578): ubifs_assert_failed [ubifs]: UBIFS assert failed: c->bi.dd_growth >= 0, in fs/ubifs/budget.c:554 UBIFS warning (ubi0:0 pid 2578): ubifs_ro_mode [ubifs]: switched to read-only mode, error -22 Workqueue: writeback wb_workfn (flush-ubifs_0_0) Call Trace: ubifs_ro_mode+0x54/0x60 [ubifs] ubifs_assert_failed+0x4b/0x80 [ubifs] ubifs_release_budget+0x468/0x5a0 [ubifs] ubifs_release_dirty_inode_budget+0x53/0x80 [ubifs] ubifs_write_inode+0x121/0x1f0 [ubifs] ... wb_workfn+0x283/0x7b0 Fix it by holding tmpfile ubifs inode lock during ubifs_jnl_update(). Similar problem exists in whiteout renaming, but previous fix("ubifs: Rename whiteout atomically") has solved the problem. Fixes: 474b93704f32163 ("ubifs: Implement O_TMPFILE") Link: https://bugzilla.kernel.org/show_bug.cgi?id=214765 Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com> Signed-off-by: Richard Weinberger <richard@nod.at>
Diffstat (limited to 'fs/ubifs')
-rw-r--r--fs/ubifs/dir.c60
1 files changed, 30 insertions, 30 deletions
diff --git a/fs/ubifs/dir.c b/fs/ubifs/dir.c
index f2a6b45bfdae..faca567ef06b 100644
--- a/fs/ubifs/dir.c
+++ b/fs/ubifs/dir.c
@@ -397,6 +397,32 @@ out_free:
return ERR_PTR(err);
}
+/**
+ * lock_2_inodes - a wrapper for locking two UBIFS inodes.
+ * @inode1: first inode
+ * @inode2: second inode
+ *
+ * We do not implement any tricks to guarantee strict lock ordering, because
+ * VFS has already done it for us on the @i_mutex. So this is just a simple
+ * wrapper function.
+ */
+static void lock_2_inodes(struct inode *inode1, struct inode *inode2)
+{
+ mutex_lock_nested(&ubifs_inode(inode1)->ui_mutex, WB_MUTEX_1);
+ mutex_lock_nested(&ubifs_inode(inode2)->ui_mutex, WB_MUTEX_2);
+}
+
+/**
+ * unlock_2_inodes - a wrapper for unlocking two UBIFS inodes.
+ * @inode1: first inode
+ * @inode2: second inode
+ */
+static void unlock_2_inodes(struct inode *inode1, struct inode *inode2)
+{
+ mutex_unlock(&ubifs_inode(inode2)->ui_mutex);
+ mutex_unlock(&ubifs_inode(inode1)->ui_mutex);
+}
+
static int ubifs_tmpfile(struct user_namespace *mnt_userns, struct inode *dir,
struct dentry *dentry, umode_t mode)
{
@@ -404,7 +430,7 @@ static int ubifs_tmpfile(struct user_namespace *mnt_userns, struct inode *dir,
struct ubifs_info *c = dir->i_sb->s_fs_info;
struct ubifs_budget_req req = { .new_ino = 1, .new_dent = 1};
struct ubifs_budget_req ino_req = { .dirtied_ino = 1 };
- struct ubifs_inode *ui, *dir_ui = ubifs_inode(dir);
+ struct ubifs_inode *ui;
int err, instantiated = 0;
struct fscrypt_name nm;
@@ -452,18 +478,18 @@ static int ubifs_tmpfile(struct user_namespace *mnt_userns, struct inode *dir,
instantiated = 1;
mutex_unlock(&ui->ui_mutex);
- mutex_lock(&dir_ui->ui_mutex);
+ lock_2_inodes(dir, inode);
err = ubifs_jnl_update(c, dir, &nm, inode, 1, 0);
if (err)
goto out_cancel;
- mutex_unlock(&dir_ui->ui_mutex);
+ unlock_2_inodes(dir, inode);
ubifs_release_budget(c, &req);
return 0;
out_cancel:
- mutex_unlock(&dir_ui->ui_mutex);
+ unlock_2_inodes(dir, inode);
out_inode:
make_bad_inode(inode);
if (!instantiated)
@@ -690,32 +716,6 @@ static int ubifs_dir_release(struct inode *dir, struct file *file)
return 0;
}
-/**
- * lock_2_inodes - a wrapper for locking two UBIFS inodes.
- * @inode1: first inode
- * @inode2: second inode
- *
- * We do not implement any tricks to guarantee strict lock ordering, because
- * VFS has already done it for us on the @i_mutex. So this is just a simple
- * wrapper function.
- */
-static void lock_2_inodes(struct inode *inode1, struct inode *inode2)
-{
- mutex_lock_nested(&ubifs_inode(inode1)->ui_mutex, WB_MUTEX_1);
- mutex_lock_nested(&ubifs_inode(inode2)->ui_mutex, WB_MUTEX_2);
-}
-
-/**
- * unlock_2_inodes - a wrapper for unlocking two UBIFS inodes.
- * @inode1: first inode
- * @inode2: second inode
- */
-static void unlock_2_inodes(struct inode *inode1, struct inode *inode2)
-{
- mutex_unlock(&ubifs_inode(inode2)->ui_mutex);
- mutex_unlock(&ubifs_inode(inode1)->ui_mutex);
-}
-
static int ubifs_link(struct dentry *old_dentry, struct inode *dir,
struct dentry *dentry)
{