Commits
Tyler Hicks committed 60d65f1f07a
eCryptfs: Fix lockdep warning in miscdev operations
Don't grab the daemon mutex while holding the message context mutex.
Addresses this lockdep warning:
ecryptfsd/2141 is trying to acquire lock:
(&ecryptfs_msg_ctx_arr[i].mux){+.+.+.}, at: [<ffffffffa029c213>] ecryptfs_miscdev_read+0x143/0x470 [ecryptfs]
but task is already holding lock:
(&(*daemon)->mux){+.+...}, at: [<ffffffffa029c2ec>] ecryptfs_miscdev_read+0x21c/0x470 [ecryptfs]
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #1 (&(*daemon)->mux){+.+...}:
[<ffffffff810a3b8d>] lock_acquire+0x9d/0x220
[<ffffffff8151c6da>] __mutex_lock_common+0x5a/0x4b0
[<ffffffff8151cc64>] mutex_lock_nested+0x44/0x50
[<ffffffffa029c5d7>] ecryptfs_send_miscdev+0x97/0x120 [ecryptfs]
[<ffffffffa029b744>] ecryptfs_send_message+0x134/0x1e0 [ecryptfs]
[<ffffffffa029a24e>] ecryptfs_generate_key_packet_set+0x2fe/0xa80 [ecryptfs]
[<ffffffffa02960f8>] ecryptfs_write_metadata+0x108/0x250 [ecryptfs]
[<ffffffffa0290f80>] ecryptfs_create+0x130/0x250 [ecryptfs]
[<ffffffff811963a4>] vfs_create+0xb4/0x120
[<ffffffff81197865>] do_last+0x8c5/0xa10
[<ffffffff811998f9>] path_openat+0xd9/0x460
[<ffffffff81199da2>] do_filp_open+0x42/0xa0
[<ffffffff81187998>] do_sys_open+0xf8/0x1d0
[<ffffffff81187a91>] sys_open+0x21/0x30
[<ffffffff81527d69>] system_call_fastpath+0x16/0x1b
-> #0 (&ecryptfs_msg_ctx_arr[i].mux){+.+.+.}:
[<ffffffff810a3418>] __lock_acquire+0x1bf8/0x1c50
[<ffffffff810a3b8d>] lock_acquire+0x9d/0x220
[<ffffffff8151c6da>] __mutex_lock_common+0x5a/0x4b0
[<ffffffff8151cc64>] mutex_lock_nested+0x44/0x50
[<ffffffffa029c213>] ecryptfs_miscdev_read+0x143/0x470 [ecryptfs]
[<ffffffff811887d3>] vfs_read+0xb3/0x180
[<ffffffff811888ed>] sys_read+0x4d/0x90
[<ffffffff81527d69>] system_call_fastpath+0x16/0x1b
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>