/* -*- mode: c; c-basic-offset: 8; -*-
 * vim: noexpandtab sw=8 ts=8 sts=0:
 *
 * heartbeat.c
 *
 * Register ourselves with the heartbaet service, keep our node maps
 * up to date, and fire off recovery when needed.
 *
 * Copyright (C) 2002, 2004 Oracle.  All rights reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public
 * License along with this program; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 021110-1307, USA.
 */

#include <linux/fs.h>
#include <linux/types.h>
#include <linux/highmem.h>

#include <cluster/masklog.h>

#include "ocfs2.h"

#include "alloc.h"
#include "heartbeat.h"
#include "inode.h"
#include "journal.h"
#include "ocfs2_trace.h"

#include "buffer_head_io.h"

static inline void __ocfs2_node_map_set_bit(struct ocfs2_node_map *map,
					    int bit);
static inline void __ocfs2_node_map_clear_bit(struct ocfs2_node_map *map,
					      int bit);

/* special case -1 for now
 * TODO: should *really* make sure the calling func never passes -1!!  */
static void ocfs2_node_map_init(struct ocfs2_node_map *map)
{
	map->num_nodes = OCFS2_NODE_MAP_MAX_NODES;
	memset(map->map, 0, BITS_TO_LONGS(OCFS2_NODE_MAP_MAX_NODES) *
	       sizeof(unsigned long));
}

void ocfs2_init_node_maps(struct ocfs2_super *osb)
{
	spin_lock_init(&osb->node_map_lock);
	ocfs2_node_map_init(&osb->osb_recovering_orphan_dirs);
}

void ocfs2_do_node_down(int node_num, void *data)
{
	struct ocfs2_super *osb = data;

	BUG_ON(osb->node_num == node_num);

	trace_ocfs2_do_node_down(node_num);

	if (!osb->cconn) {
		/*
		 * No cluster connection means we're not even ready to
		 * participate yet.  We check the slots after the cluster
		 * comes up, so we will notice the node death then.  We
		 * can safely ignore it here.
		 */
		return;
	}

	ocfs2_recovery_thread(osb, node_num);
}

static inline void __ocfs2_node_map_set_bit(struct ocfs2_node_map *map,
					    int bit)
{
	set_bit(bit, map->map);
}

void ocfs2_node_map_set_bit(struct ocfs2_super *osb,
			    struct ocfs2_node_map *map,
			    int bit)
{
	if (bit==-1)
		return;
	BUG_ON(bit >= map->num_nodes);
	spin_lock(&osb->node_map_lock);
	__ocfs2_node_map_set_bit(map, bit);
	spin_unlock(&osb->node_map_lock);
}

static inline void __ocfs2_node_map_clear_bit(struct ocfs2_node_map *map,
					      int bit)
{
	clear_bit(bit, map->map);
}

void ocfs2_node_map_clear_bit(struct ocfs2_super *osb,
			      struct ocfs2_node_map *map,
			      int bit)
{
	if (bit==-1)
		return;
	BUG_ON(bit >= map->num_nodes);
	spin_lock(&osb->node_map_lock);
	__ocfs2_node_map_clear_bit(map, bit);
	spin_unlock(&osb->node_map_lock);
}

int ocfs2_node_map_test_bit(struct ocfs2_super *osb,
			    struct ocfs2_node_map *map,
			    int bit)
{
	int ret;
	if (bit >= map->num_nodes) {
		mlog(ML_ERROR, "bit=%d map->num_nodes=%d\n", bit, map->num_nodes);
		BUG();
	}
	spin_lock(&osb->node_map_lock);
	ret = test_bit(bit, map->map);
	spin_unlock(&osb->node_map_lock);
	return ret;
}

6e77f6dfba96c543e55b6672d5a37e'/><table><tr><td colspan='2'/></tr><tr><td class='label'>context:</td><td class='ctrl'><select name='context' onchange='this.form.submit();'><option value='1'>1</option><option value='2'>2</option><option value='3' selected='selected'>3</option><option value='4'>4</option><option value='5'>5</option><option value='6'>6</option><option value='7'>7</option><option value='8'>8</option><option value='9'>9</option><option value='10'>10</option><option value='15'>15</option><option value='20'>20</option><option value='25'>25</option><option value='30'>30</option><option value='35'>35</option><option value='40'>40</option></select></td></tr><tr><td class='label'>space:</td><td class='ctrl'><select name='ignorews' onchange='this.form.submit();'><option value='0' selected='selected'>include</option><option value='1'>ignore</option></select></td></tr><tr><td class='label'>mode:</td><td class='ctrl'><select name='dt' onchange='this.form.submit();'><option value='0' selected='selected'>unified</option><option value='1'>ssdiff</option><option value='2'>stat only</option></select></td></tr><tr><td/><td class='ctrl'><noscript><input type='submit' value='reload'/></noscript></td></tr></table></form></div><table summary='commit info' class='commit-info'>
<tr><th>author</th><td>Linus Torvalds &lt;torvalds@linux-foundation.org&gt;</td><td class='right'>2017-01-29 13:50:06 -0800</td></tr>
<tr><th>committer</th><td>Linus Torvalds &lt;torvalds@linux-foundation.org&gt;</td><td class='right'>2017-01-29 13:50:06 -0800</td></tr>
<tr><th>commit</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/net/ipv6/netfilter/nft_redir_ipv6.c?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e'>39cb2c9a316e77f6dfba96c543e55b6672d5a37e</a> (<a href='/cgit.cgi/linux/net-next.git/patch/net/ipv6/netfilter/nft_redir_ipv6.c?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e'>patch</a>)</td></tr>
<tr><th>tree</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/tree/?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e'>98fe974ee4e20121253de7f61fc8d01bdb3821c1</a> /<a href='/cgit.cgi/linux/net-next.git/tree/net/ipv6/netfilter/nft_redir_ipv6.c?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e'>net/ipv6/netfilter/nft_redir_ipv6.c</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/net/ipv6/netfilter/nft_redir_ipv6.c?id=2c5d9555d6d937966d79d4c6529a5f7b9206e405'>2c5d9555d6d937966d79d4c6529a5f7b9206e405</a> (<a href='/cgit.cgi/linux/net-next.git/diff/net/ipv6/netfilter/nft_redir_ipv6.c?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e&amp;id2=2c5d9555d6d937966d79d4c6529a5f7b9206e405'>diff</a>)</td></tr></table>
<div class='commit-subject'>drm/i915: Check for NULL i915_vma in intel_unpin_fb_obj()</div><div class='commit-msg'>I've seen this trigger twice now, where the i915_gem_object_to_ggtt()
call in intel_unpin_fb_obj() returns NULL, resulting in an oops
immediately afterwards as the (inlined) call to i915_vma_unpin_fence()
tries to dereference it.

It seems to be some race condition where the object is going away at
shutdown time, since both times happened when shutting down the X
server.  The call chains were different:

 - VT ioctl(KDSETMODE, KD_TEXT):

    intel_cleanup_plane_fb+0x5b/0xa0 [i915]
    drm_atomic_helper_cleanup_planes+0x6f/0x90 [drm_kms_helper]
    intel_atomic_commit_tail+0x749/0xfe0 [i915]
    intel_atomic_commit+0x3cb/0x4f0 [i915]
    drm_atomic_commit+0x4b/0x50 [drm]
    restore_fbdev_mode+0x14c/0x2a0 [drm_kms_helper]
    drm_fb_helper_restore_fbdev_mode_unlocked+0x34/0x80 [drm_kms_helper]
    drm_fb_helper_set_par+0x2d/0x60 [drm_kms_helper]
    intel_fbdev_set_par+0x18/0x70 [i915]
    fb_set_var+0x236/0x460
    fbcon_blank+0x30f/0x350
    do_unblank_screen+0xd2/0x1a0
    vt_ioctl+0x507/0x12a0
    tty_ioctl+0x355/0xc30
    do_vfs_ioctl+0xa3/0x5e0
    SyS_ioctl+0x79/0x90
    entry_SYSCALL_64_fastpath+0x13/0x94

 - i915 unpin_work workqueue:

    intel_unpin_work_fn+0x58/0x140 [i915]
    process_one_work+0x1f1/0x480
    worker_thread+0x48/0x4d0
    kthread+0x101/0x140

and this patch purely papers over the issue by adding a NULL pointer
check and a WARN_ON_ONCE() to avoid the oops that would then generally
make the machine unresponsive.

Other callers of i915_gem_object_to_ggtt() seem to also check for the
returned pointer being NULL and warn about it, so this clearly has
happened before in other places.

[ Reported it originally to the i915 developers on Jan 8, applying the
  ugly workaround on my own now after triggering the problem for the
  second time with no feedback.

  This is likely to be the same bug reported as

     https://bugs.freedesktop.org/show_bug.cgi?id=98829
     https://bugs.freedesktop.org/show_bug.cgi?id=99134

  which has a patch for the underlying problem, but it hasn't gotten to
  me, so I'm applying the workaround. ]

Cc: Daniel Vetter &lt;daniel.vetter@intel.com&gt;
Cc: Jani Nikula &lt;jani.nikula@linux.intel.com&gt;
Cc: Ville Syrjälä &lt;ville.syrjala@linux.intel.com&gt;
Cc: Chris Wilson &lt;chris@chris-wilson.co.uk&gt;
Cc: Maarten Lankhorst &lt;maarten.lankhorst@linux.intel.com&gt;
Cc: Tvrtko Ursulin &lt;tvrtko.ursulin@intel.com&gt;
Cc: Imre Deak &lt;imre.deak@intel.com&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</div><div class='diffstat-header'><a href='/cgit.cgi/linux/net-next.git/diff/?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e'>Diffstat</a> (limited to 'net/ipv6/netfilter/nft_redir_ipv6.c')</div><table summary='diffstat' class='diffstat'>