/* Copyright (C) 2014-2017 B.A.T.M.A.N. contributors: * * Linus Lüssing * * This program is free software; you can redistribute it and/or * modify it under the terms of version 2 of the GNU General Public * License as published by the Free Software Foundation. * * 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 . */ #ifndef _NET_BATMAN_ADV_MULTICAST_H_ #define _NET_BATMAN_ADV_MULTICAST_H_ #include "main.h" struct seq_file; struct sk_buff; /** * enum batadv_forw_mode - the way a packet should be forwarded as * @BATADV_FORW_ALL: forward the packet to all nodes (currently via classic * flooding) * @BATADV_FORW_SINGLE: forward the packet to a single node (currently via the * BATMAN unicast routing protocol) * @BATADV_FORW_NONE: don't forward, drop it */ enum batadv_forw_mode { BATADV_FORW_ALL, BATADV_FORW_SINGLE, BATADV_FORW_NONE, }; #ifdef CONFIG_BATMAN_ADV_MCAST enum batadv_forw_mode batadv_mcast_forw_mode(struct batadv_priv *bat_priv, struct sk_buff *skb, struct batadv_orig_node **mcast_single_orig); void batadv_mcast_init(struct batadv_priv *bat_priv); int batadv_mcast_flags_seq_print_text(struct seq_file *seq, void *offset); void batadv_mcast_free(struct batadv_priv *bat_priv); void batadv_mcast_purge_orig(struct batadv_orig_node *orig_node); #else static inline enum batadv_forw_mode batadv_mcast_forw_mode(struct batadv_priv *bat_priv, struct sk_buff *skb, struct batadv_orig_node **mcast_single_orig) { return BATADV_FORW_ALL; } static inline int batadv_mcast_init(struct batadv_priv *bat_priv) { return 0; } static inline void batadv_mcast_free(struct batadv_priv *bat_priv) { } static inline void batadv_mcast_purge_orig(struct batadv_orig_node *orig_node) { } #endif /* CONFIG_BATMAN_ADV_MCAST */ #endif /* _NET_BATMAN_ADV_MULTICAST_H_ */ 95dbf8985f656675b5bde610723a29cbce3fa7'>diff
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authorEric W. Biederman <ebiederm@xmission.com>2017-01-03 14:18:43 +1300
committerEric W. Biederman <ebiederm@xmission.com>2017-01-10 13:34:43 +1300
commit3895dbf8985f656675b5bde610723a29cbce3fa7 (patch)
tree91d4517f09918fd573998eb40b8f35f08ed1c470 /net/ipv6
parent0c744ea4f77d72b3dcebb7a8f2684633ec79be88 (diff)
mnt: Protect the mountpoint hashtable with mount_lock
Protecting the mountpoint hashtable with namespace_sem was sufficient until a call to umount_mnt was added to mntput_no_expire. At which point it became possible for multiple calls of put_mountpoint on the same hash chain to happen on the same time. Kristen Johansen <kjlx@templeofstupid.com> reported: > This can cause a panic when simultaneous callers of put_mountpoint > attempt to free the same mountpoint. This occurs because some callers > hold the mount_hash_lock, while others hold the namespace lock. Some > even hold both. > > In this submitter's case, the panic manifested itself as a GP fault in > put_mountpoint() when it called hlist_del() and attempted to dereference > a m_hash.pprev that had been poisioned by another thread. Al Viro observed that the simple fix is to switch from using the namespace_sem to the mount_lock to protect the mountpoint hash table. I have taken Al's suggested patch moved put_mountpoint in pivot_root (instead of taking mount_lock an additional time), and have replaced new_mountpoint with get_mountpoint a function that does the hash table lookup and addition under the mount_lock. The introduction of get_mounptoint ensures that only the mount_lock is needed to manipulate the mountpoint hashtable. d_set_mounted is modified to only set DCACHE_MOUNTED if it is not already set. This allows get_mountpoint to use the setting of DCACHE_MOUNTED to ensure adding a struct mountpoint for a dentry happens exactly once. Cc: stable@vger.kernel.org Fixes: ce07d891a089 ("mnt: Honor MNT_LOCKED when detaching mounts") Reported-by: Krister Johansen <kjlx@templeofstupid.com> Suggested-by: Al Viro <viro@ZenIV.linux.org.uk> Acked-by: Al Viro <viro@ZenIV.linux.org.uk> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Diffstat (limited to 'net/ipv6')