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f6f8285132
The buf_lock cannot be held while populating the inodes, so make the backend pass forward an allocated and filled buffer instead. This solves the following backtrace. The effect is that "buf" is only ever used to notify the backends that something was written to it, and shouldn't be used in the read path. To replace the buf_lock during the read path, isolate the open/read/close loop with a separate mutex to maintain serialized access to the backend. Note that is is up to the pstore backend to cope if the (*write)() path is called in the middle of the read path. [ 59.691019] BUG: sleeping function called from invalid context at .../mm/slub.c:847 [ 59.691019] in_atomic(): 0, irqs_disabled(): 1, pid: 1819, name: mount [ 59.691019] Pid: 1819, comm: mount Not tainted 3.0.8 #1 [ 59.691019] Call Trace: [ 59.691019] [<810252d5>] __might_sleep+0xc3/0xca [ 59.691019] [<810a26e6>] kmem_cache_alloc+0x32/0xf3 [ 59.691019] [<810b53ac>] ? __d_lookup_rcu+0x6f/0xf4 [ 59.691019] [<810b68b1>] alloc_inode+0x2a/0x64 [ 59.691019] [<810b6903>] new_inode+0x18/0x43 [ 59.691019] [<81142447>] pstore_get_inode.isra.1+0x11/0x98 [ 59.691019] [<81142623>] pstore_mkfile+0xae/0x26f [ 59.691019] [<810a2a66>] ? kmem_cache_free+0x19/0xb1 [ 59.691019] [<8116c821>] ? ida_get_new_above+0x140/0x158 [ 59.691019] [<811708ea>] ? __init_rwsem+0x1e/0x2c [ 59.691019] [<810b67e8>] ? inode_init_always+0x111/0x1b0 [ 59.691019] [<8102127e>] ? should_resched+0xd/0x27 [ 59.691019] [<8137977f>] ? _cond_resched+0xd/0x21 [ 59.691019] [<81142abf>] pstore_get_records+0x52/0xa7 [ 59.691019] [<8114254b>] pstore_fill_super+0x7d/0x91 [ 59.691019] [<810a7ff5>] mount_single+0x46/0x82 [ 59.691019] [<8114231a>] pstore_mount+0x15/0x17 [ 59.691019] [<811424ce>] ? pstore_get_inode.isra.1+0x98/0x98 [ 59.691019] [<810a8199>] mount_fs+0x5a/0x12d [ 59.691019] [<810b9174>] ? alloc_vfsmnt+0xa4/0x14a [ 59.691019] [<810b9474>] vfs_kern_mount+0x4f/0x7d [ 59.691019] [<810b9d7e>] do_kern_mount+0x34/0xb2 [ 59.691019] [<810bb15f>] do_mount+0x5fc/0x64a [ 59.691019] [<810912fb>] ? strndup_user+0x2e/0x3f [ 59.691019] [<810bb3cb>] sys_mount+0x66/0x99 [ 59.691019] [<8137b537>] sysenter_do_call+0x12/0x26 Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Tony Luck <tony.luck@intel.com>
68 lines
2.0 KiB
C
68 lines
2.0 KiB
C
/*
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* Persistent Storage - pstore.h
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*
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* Copyright (C) 2010 Intel Corporation <tony.luck@intel.com>
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*
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* This code is the generic layer to export data records from platform
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* level persistent storage via a file system.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#ifndef _LINUX_PSTORE_H
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#define _LINUX_PSTORE_H
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/* types */
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enum pstore_type_id {
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PSTORE_TYPE_DMESG = 0,
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PSTORE_TYPE_MCE = 1,
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PSTORE_TYPE_UNKNOWN = 255
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};
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struct pstore_info {
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struct module *owner;
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char *name;
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spinlock_t buf_lock; /* serialize access to 'buf' */
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char *buf;
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size_t bufsize;
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struct mutex read_mutex; /* serialize open/read/close */
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int (*open)(struct pstore_info *psi);
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int (*close)(struct pstore_info *psi);
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ssize_t (*read)(u64 *id, enum pstore_type_id *type,
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struct timespec *time, char **buf,
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struct pstore_info *psi);
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int (*write)(enum pstore_type_id type, u64 *id,
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unsigned int part, size_t size, struct pstore_info *psi);
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int (*erase)(enum pstore_type_id type, u64 id,
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struct pstore_info *psi);
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void *data;
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};
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#ifdef CONFIG_PSTORE
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extern int pstore_register(struct pstore_info *);
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extern int pstore_write(enum pstore_type_id type, char *buf, size_t size);
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#else
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static inline int
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pstore_register(struct pstore_info *psi)
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{
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return -ENODEV;
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}
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static inline int
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pstore_write(enum pstore_type_id type, char *buf, size_t size)
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{
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return -ENODEV;
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}
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#endif
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#endif /*_LINUX_PSTORE_H*/
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