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c455b17aff
[ Upstream commit0ed04a1847] debugfs_create_automount() stores a function pointer in d_fsdata, but since commit7c8d469877("debugfs: add support for more elaborate ->d_fsdata") debugfs_release_dentry() will free it, now conditionally on DEBUGFS_FSDATA_IS_REAL_FOPS_BIT, but that's not set for the function pointer in automount. As a result, removing an automount dentry would attempt to free the function pointer. Luckily, the only user of this (tracing) never removes it. Nevertheless, it's safer if we just handle the fsdata in one way, namely either DEBUGFS_FSDATA_IS_REAL_FOPS_BIT or allocated. Thus, change the automount to allocate it, and use the real_fops in the data to indicate whether or not automount is filled, rather than adding a type tag. At least for now this isn't actually needed, but the next changes will require it. Also check in debugfs_file_get() that it gets only called on regular files, just to make things clearer. Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
52 lines
1.4 KiB
C
52 lines
1.4 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* internal.h - declarations internal to debugfs
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*
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* Copyright (C) 2016 Nicolai Stange <nicstange@gmail.com>
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*/
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#ifndef _DEBUGFS_INTERNAL_H_
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#define _DEBUGFS_INTERNAL_H_
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struct file_operations;
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/* declared over in file.c */
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extern const struct file_operations debugfs_noop_file_operations;
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extern const struct file_operations debugfs_open_proxy_file_operations;
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extern const struct file_operations debugfs_full_proxy_file_operations;
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struct debugfs_fsdata {
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const struct file_operations *real_fops;
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union {
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/* automount_fn is used when real_fops is NULL */
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debugfs_automount_t automount;
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struct {
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refcount_t active_users;
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struct completion active_users_drained;
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};
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};
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};
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/*
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* A dentry's ->d_fsdata either points to the real fops or to a
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* dynamically allocated debugfs_fsdata instance.
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* In order to distinguish between these two cases, a real fops
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* pointer gets its lowest bit set.
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*/
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#define DEBUGFS_FSDATA_IS_REAL_FOPS_BIT BIT(0)
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/* Access BITS */
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#define DEBUGFS_ALLOW_API BIT(0)
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#define DEBUGFS_ALLOW_MOUNT BIT(1)
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#ifdef CONFIG_DEBUG_FS_ALLOW_ALL
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#define DEFAULT_DEBUGFS_ALLOW_BITS (DEBUGFS_ALLOW_MOUNT | DEBUGFS_ALLOW_API)
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#endif
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#ifdef CONFIG_DEBUG_FS_DISALLOW_MOUNT
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#define DEFAULT_DEBUGFS_ALLOW_BITS (DEBUGFS_ALLOW_API)
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#endif
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#ifdef CONFIG_DEBUG_FS_ALLOW_NONE
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#define DEFAULT_DEBUGFS_ALLOW_BITS (0)
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#endif
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#endif /* _DEBUGFS_INTERNAL_H_ */
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