/* * Copyright (c) 2015 Mellanox Technologies. All rights reserved. * * This software is available to you under a choice of one of two * licenses. You may choose to be licensed under the terms of the GNU * General Public License (GPL) Version 2, available from the file * COPYING in the main directory of this source tree, or the * OpenIB.org BSD license below: * * Redistribution and use in source and binary forms, with or * without modification, are permitted provided that the following * conditions are met: * * - Redistributions of source code must retain the above * copyright notice, this list of conditions and the following * disclaimer. * * - Redistributions in binary form must reproduce the above * copyright notice, this list of conditions and the following * disclaimer in the documentation and/or other materials * provided with the distribution. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE * SOFTWARE. */ #ifndef ISCSI_ISER_H #define ISCSI_ISER_H #define ISER_ZBVA_NOT_SUP 0x80 #define ISER_SEND_W_INV_NOT_SUP 0x40 #define ISERT_ZBVA_NOT_USED 0x80 #define ISERT_SEND_W_INV_NOT_USED 0x40 #define ISCSI_CTRL 0x10 #define ISER_HELLO 0x20 #define ISER_HELLORPLY 0x30 #define ISER_VER 0x10 #define ISER_WSV 0x08 #define ISER_RSV 0x04 /** * struct iser_cm_hdr - iSER CM header (from iSER Annex A12) * * @flags: flags support (zbva, send_w_inv) * @rsvd: reserved */ struct iser_cm_hdr { u8 flags; u8 rsvd[3]; } __packed; /** * struct iser_ctrl - iSER header of iSCSI control PDU * * @flags: opcode and read/write valid bits * @rsvd: reserved * @write_stag: write rkey * @write_va: write virtual address * @reaf_stag: read rkey * @read_va: read virtual address */ struct iser_ctrl { u8 flags; u8 rsvd[3]; __be32 write_stag; __be64 write_va; __be32 read_stag; __be64 read_va; } __packed; #endif /* ISCSI_ISER_H */ value='range'>range
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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 /include
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 'include')