/*
 * NetLabel Domain Hash Table
 *
 * This file manages the domain hash table that NetLabel uses to determine
 * which network labeling protocol to use for a given domain.  The NetLabel
 * system manages static and dynamic label mappings for network protocols such
 * as CIPSO and RIPSO.
 *
 * Author: Paul Moore <paul@paul-moore.com>
 *
 */

/*
 * (c) Copyright Hewlett-Packard Development Company, L.P., 2006, 2008
 *
 * 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, see <http://www.gnu.org/licenses/>.
 *
 */

#ifndef _NETLABEL_DOMAINHASH_H
#define _NETLABEL_DOMAINHASH_H

#include <linux/types.h>
#include <linux/rcupdate.h>
#include <linux/list.h>

#include "netlabel_addrlist.h"

/* Domain hash table size */
/* XXX - currently this number is an uneducated guess */
#define NETLBL_DOMHSH_BITSIZE       7

/* Domain mapping definition structures */
struct netlbl_domaddr_map {
	struct list_head list4;
	struct list_head list6;
};
struct netlbl_dommap_def {
	u32 type;
	union {
		struct netlbl_domaddr_map *addrsel;
		struct cipso_v4_doi *cipso;
		struct calipso_doi *calipso;
	};
};
#define netlbl_domhsh_addr4_entry(iter) \
	container_of(iter, struct netlbl_domaddr4_map, list)
struct netlbl_domaddr4_map {
	struct netlbl_dommap_def def;

	struct netlbl_af4list list;
};
#define netlbl_domhsh_addr6_entry(iter) \
	container_of(iter, struct netlbl_domaddr6_map, list)
struct netlbl_domaddr6_map {
	struct netlbl_dommap_def def;

	struct netlbl_af6list list;
};

struct netlbl_dom_map {
	char *domain;
	u16 family;
	struct netlbl_dommap_def def;

	u32 valid;
	struct list_head list;
	struct rcu_head rcu;
};

/* init function */
int netlbl_domhsh_init(u32 size);

/* Manipulate the domain hash table */
int netlbl_domhsh_add(struct netlbl_dom_map *entry,
		      struct netlbl_audit *audit_info);
int netlbl_domhsh_add_default(struct netlbl_dom_map *entry,
			      struct netlbl_audit *audit_info);
int netlbl_domhsh_remove_entry(struct netlbl_dom_map *entry,
			       struct netlbl_audit *audit_info);
int netlbl_domhsh_remove_af4(const char *domain,
			     const struct in_addr *addr,
			     const struct in_addr *mask,
			     struct netlbl_audit *audit_info);
int netlbl_domhsh_remove_af6(const char *domain,
			     const struct in6_addr *addr,
			     const struct in6_addr *mask,
			     struct netlbl_audit *audit_info);
int netlbl_domhsh_remove(const char *domain, u16 family,
			 struct netlbl_audit *audit_info);
int netlbl_domhsh_remove_default(u16 family, struct netlbl_audit *audit_info);
struct netlbl_dom_map *netlbl_domhsh_getentry(const char *domain, u16 family);
struct netlbl_dommap_def *netlbl_domhsh_getentry_af4(const char *domain,
						     __be32 addr);
#if IS_ENABLED(CONFIG_IPV6)
struct netlbl_dommap_def *netlbl_domhsh_getentry_af6(const char *domain,
						   const struct in6_addr *addr);
int netlbl_domhsh_remove_af6(const char *domain,
			     const struct in6_addr *addr,
			     const struct in6_addr *mask,
			     struct netlbl_audit *audit_info);
#endif /* IPv6 */

int netlbl_domhsh_walk(u32 *skip_bkt,
		     u32 *skip_chain,
		     int (*callback) (struct netlbl_dom_map *entry, void *arg),
		     void *cb_arg);

#endif
'>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/bridge/netfilter/ebtable_nat.c?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e'>39cb2c9a316e77f6dfba96c543e55b6672d5a37e</a> (<a href='/cgit.cgi/linux/net-next.git/patch/net/bridge/netfilter/ebtable_nat.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/bridge/netfilter/ebtable_nat.c?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e'>net/bridge/netfilter/ebtable_nat.c</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/net/bridge/netfilter/ebtable_nat.c?id=2c5d9555d6d937966d79d4c6529a5f7b9206e405'>2c5d9555d6d937966d79d4c6529a5f7b9206e405</a> (<a href='/cgit.cgi/linux/net-next.git/diff/net/bridge/netfilter/ebtable_nat.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/bridge/netfilter/ebtable_nat.c')</div><table summary='diffstat' class='diffstat'>