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List:       git-commits-head
Subject:    cifs: initialize file_info_lock
From:       "Linux Kernel Mailing List" <linux-kernel () vger ! kernel ! org>
Date:       2017-01-31 21:57:06
Message-ID: 20170131215706.6B959660BF1 () gitolite ! kernel ! org
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Web:        https://git.kernel.org/torvalds/c/81ddd8c0c5e1cb41184d66567140cb48c53eb3d1
Commit:     81ddd8c0c5e1cb41184d66567140cb48c53eb3d1
Parent:     2eabb8b8d68bc9c7779ba8b04bec8d4f8baed0bc
Refname:    refs/heads/master
Author:     Rabin Vincent <rabinv@axis.com>
AuthorDate: Fri Jan 13 15:00:16 2017 +0100
Committer:  Steve French <smfrench@gmail.com>
CommitDate: Sat Jan 14 14:58:29 2017 -0600

    cifs: initialize file_info_lock
    
    Reviewed-by: Jeff Layton <jlayton@redhat.com>
    CC: Stable <stable@vger.kernel.org>
    
    file_info_lock is not initalized in initiate_cifs_search(), leading to the
    following splat after a simple "mount.cifs ... dir && ls dir/":
    
     BUG: spinlock bad magic on CPU#0, ls/486
      lock: 0xffff880009301110, .magic: 00000000, .owner: <none>/-1, .owner_cpu: 0
     CPU: 0 PID: 486 Comm: ls Not tainted 4.9.0 #27
     Hardware name: QEMU Standard PC (i440FX + PIIX, 1996)
      ffffc900042f3db0 ffffffff81327533 0000000000000000 ffff880009301110
      ffffc900042f3dd0 ffffffff810baf75 ffff880009301110 ffffffff817ae077
      ffffc900042f3df0 ffffffff810baff6 ffff880009301110 ffff880008d69900
     Call Trace:
      [<ffffffff81327533>] dump_stack+0x65/0x92
      [<ffffffff810baf75>] spin_dump+0x85/0xe0
      [<ffffffff810baff6>] spin_bug+0x26/0x30
      [<ffffffff810bb159>] do_raw_spin_lock+0xe9/0x130
      [<ffffffff8159ad2f>] _raw_spin_lock+0x1f/0x30
      [<ffffffff8127e50d>] cifs_closedir+0x4d/0x100
      [<ffffffff81181cfd>] __fput+0x5d/0x160
      [<ffffffff81181e3e>] ____fput+0xe/0x10
      [<ffffffff8109410e>] task_work_run+0x7e/0xa0
      [<ffffffff81002512>] exit_to_usermode_loop+0x92/0xa0
      [<ffffffff810026f9>] syscall_return_slowpath+0x49/0x50
      [<ffffffff8159b484>] entry_SYSCALL_64_fastpath+0xa7/0xa9
    
    Fixes: 3afca265b5f53a0 ("Clarify locking of cifs file and tcon structures and make more granular")
    Signed-off-by: Rabin Vincent <rabinv@axis.com>
    Signed-off-by: Steve French <smfrench@gmail.com>
---
 fs/cifs/readdir.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/fs/cifs/readdir.c b/fs/cifs/readdir.c
index 8f6a2a5..a27fc87 100644
--- a/fs/cifs/readdir.c
+++ b/fs/cifs/readdir.c
@@ -285,6 +285,7 @@ initiate_cifs_search(const unsigned int xid, struct file *file)
 			rc = -ENOMEM;
 			goto error_exit;
 		}
+		spin_lock_init(&cifsFile->file_info_lock);
 		file->private_data = cifsFile;
 		cifsFile->tlink = cifs_get_tlink(tlink);
 		tcon = tlink_tcon(tlink);
--
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