On Fri, 2017-01-13 at 15:00 +0100, Rabin Vincent wrote:
> From: Rabin Vincent <rabinv@xxxxxxxx>
>
> 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@xxxxxxxx>
> ---
> 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);
Reviewed-by: Jeff Layton <jlayton@xxxxxxxxxx>
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