Skip to main content

Browse the archive

Revision dbf520a9d7d4d5ba28d2947be11e34099a5e3e20 authored by Paul Walmsley on 31 March 2013, 00:04:40 UTC, committed by Linus Torvalds on 31 March 2013, 18:38:33 UTC 
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 <paul@pwsan.com>
Cc: Mandeep Singh Baines <msb@chromium.org>
Cc: Jeff Layton <jlayton@redhat.com>
Cc: Shawn Guo <shawn.guo@linaro.org>
Cc: <maciej.rutecki@gmail.com>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Ben Chan <benchan@chromium.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent 13d2080
Raw File
stacktrace.c 
/*
 * Stack trace support for Microblaze.
 *
 * Copyright (C) 2009 Michal Simek <monstr@monstr.eu>
 * Copyright (C) 2009 PetaLogix
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License. See the file "COPYING" in the main directory of this archive
 * for more details.
 */

#include <linux/export.h>
#include <linux/sched.h>
#include <linux/stacktrace.h>
#include <linux/thread_info.h>
#include <linux/ptrace.h>
#include <asm/unwind.h>

void save_stack_trace(struct stack_trace *trace)
{
	/* Exclude our helper functions from the trace*/
	trace->skip += 2;
	microblaze_unwind(NULL, trace);
}
EXPORT_SYMBOL_GPL(save_stack_trace);

void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
{
	microblaze_unwind(tsk, trace);
}
EXPORT_SYMBOL_GPL(save_stack_trace_tsk);
back to top