From: Zhihao Cheng <chengzhihao1@huawei.com> stable inclusion from stable-5.10.52 commit ac2e498ab222121da39a659a5328f10d2d078d87 bugzilla: 175542 https://gitee.com/openeuler/kernel/issues/I4DTKU Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- [ Upstream commit a801fcfeef96702fa3f9b22ad56c5eb1989d9221 ] xfstests-generic/476 reports a warning message as below: WARNING: CPU: 2 PID: 30347 at fs/inode.c:361 inc_nlink+0x52/0x70 Call Trace: do_rename+0x502/0xd40 [ubifs] ubifs_rename+0x8b/0x180 [ubifs] vfs_rename+0x476/0x1080 do_renameat2+0x67c/0x7b0 __x64_sys_renameat2+0x6e/0x90 do_syscall_64+0x66/0xe0 entry_SYSCALL_64_after_hwframe+0x44/0xae Following race case can cause this: rename_whiteout(Thread 1) wb_workfn(Thread 2) ubifs_rename do_rename __writeback_single_inode spin_lock(&inode->i_lock) whiteout->i_state |= I_LINKABLE inode->i_state &= ~dirty; ---- How race happens on i_state: (tmp = whiteout->i_state | I_LINKABLE) (tmp = inode->i_state & ~dirty) (whiteout->i_state = tmp) (inode->i_state = tmp) ---- spin_unlock(&inode->i_lock) inc_nlink(whiteout) WARN_ON(!(inode->i_state & I_LINKABLE)) !!! Fix to add i_lock to avoid i_state update race condition. Fixes: 9e0a1fff8db56ea ("ubifs: Implement RENAME_WHITEOUT") Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com> Signed-off-by: Richard Weinberger <richard@nod.at> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Chen Jun <chenjun102@huawei.com> Acked-by: Weilong Chen <chenweilong@huawei.com> Signed-off-by: Chen Jun <chenjun102@huawei.com> --- fs/ubifs/dir.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/fs/ubifs/dir.c b/fs/ubifs/dir.c index 08fde777c324..ad90a3a64293 100644 --- a/fs/ubifs/dir.c +++ b/fs/ubifs/dir.c @@ -1335,7 +1335,10 @@ static int do_rename(struct inode *old_dir, struct dentry *old_dentry, goto out_release; } + spin_lock(&whiteout->i_lock); whiteout->i_state |= I_LINKABLE; + spin_unlock(&whiteout->i_lock); + whiteout_ui = ubifs_inode(whiteout); whiteout_ui->data = dev; whiteout_ui->data_len = ubifs_encode_dev(dev, MKDEV(0, 0)); @@ -1428,7 +1431,11 @@ static int do_rename(struct inode *old_dir, struct dentry *old_dentry, inc_nlink(whiteout); mark_inode_dirty(whiteout); + + spin_lock(&whiteout->i_lock); whiteout->i_state &= ~I_LINKABLE; + spin_unlock(&whiteout->i_lock); + iput(whiteout); } -- 2.20.1