Revert "lockdep: check that no locks held at freeze time"
authorPaul Walmsley <[email protected]>
Sun, 31 Mar 2013 00:04:40 +0000 (00:04 +0000)
committerLinus Torvalds <[email protected]>
Sun, 31 Mar 2013 18:38:33 +0000 (11:38 -0700)
commitdbf520a9d7d4d5ba28d2947be11e34099a5e3e20
tree29e7a07a13a76a89b3c175c58592b2d3b176cfa5
parent13d2080db3472b3399ba32e6026960de5d32a344
Revert "lockdep: check that no locks held at freeze time"

This reverts commit 6aa9707099c4b25700940eb3d016f16c4434360d.

Commit 6aa9707099c4 ("lockdep: check that no locks held at freeze time")
causes problems with NFS root filesystems.  The failures were noticed on
OMAP2 and 3 boards during kernel init:

  [ BUG: swapper/0/1 still has locks held! ]
  3.9.0-rc3-00344-ga937536 #1 Not tainted
  -------------------------------------
  1 lock held by swapper/0/1:
   #0:  (&type->s_umount_key#13/1){+.+.+.}, at: [<c011e84c>] sget+0x248/0x574

  stack backtrace:
    rpc_wait_bit_killable
    __wait_on_bit
    out_of_line_wait_on_bit
    __rpc_execute
    rpc_run_task
    rpc_call_sync
    nfs_proc_get_root
    nfs_get_root
    nfs_fs_mount_common
    nfs_try_mount
    nfs_fs_mount
    mount_fs
    vfs_kern_mount
    do_mount
    sys_mount
    do_mount_root
    mount_root
    prepare_namespace
    kernel_init_freeable
    kernel_init

Although the rootfs mounts, the system is unstable.  Here's a transcript
from a PM test:

  http://www.pwsan.com/omap/testlogs/test_v3.9-rc3/20130317194234/pm/37xxevm/37xxevm_log.txt

Here's what the test log should look like:

  http://www.pwsan.com/omap/testlogs/test_v3.8/20130218214403/pm/37xxevm/37xxevm_log.txt

Mailing list discussion is here:

  http://lkml.org/lkml/2013/3/4/221

Deal with this for v3.9 by reverting the problem commit, until folks can
figure out the right long-term course of action.

Signed-off-by: Paul Walmsley <[email protected]>
Cc: Mandeep Singh Baines <[email protected]>
Cc: Jeff Layton <[email protected]>
Cc: Shawn Guo <[email protected]>
Cc: <[email protected]>
Cc: Fengguang Wu <[email protected]>
Cc: Trond Myklebust <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Ben Chan <[email protected]>
Cc: Oleg Nesterov <[email protected]>
Cc: Tejun Heo <[email protected]>
Cc: Rafael J. Wysocki <[email protected]>
Cc: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
include/linux/debug_locks.h
include/linux/freezer.h
kernel/exit.c
kernel/lockdep.c