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Revision 6b7339f4c31ad69c8e9c0b2859276e22cf72176d authored by Kirill A. Shutemov on 06 July 2015, 20:18:37 UTC, committed by Linus Torvalds on 09 July 2015, 18:12:48 UTC 
mm: avoid setting up anonymous pages into file mapping
 
Reading page fault handler code I've noticed that under right
circumstances kernel would map anonymous pages into file mappings: if
the VMA doesn't have vm_ops->fault() and the VMA wasn't fully populated
on ->mmap(), kernel would handle page fault to not populated pte with
do_anonymous_page().

Let's change page fault handler to use do_anonymous_page() only on
anonymous VMA (->vm_ops == NULL) and make sure that the VMA is not
shared.

For file mappings without vm_ops->fault() or shred VMA without vm_ops,
page fault on pte_none() entry would lead to SIGBUS.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Willy Tarreau <w@1wt.eu>
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent 883a2df
Raw File
trace.h 
/*
 * f2fs IO tracer
 *
 * Copyright (c) 2014 Motorola Mobility
 * Copyright (c) 2014 Jaegeuk Kim <jaegeuk@kernel.org>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */
#ifndef __F2FS_TRACE_H__
#define __F2FS_TRACE_H__

#ifdef CONFIG_F2FS_IO_TRACE
#include <trace/events/f2fs.h>

enum file_type {
	__NORMAL_FILE,
	__DIR_FILE,
	__NODE_FILE,
	__META_FILE,
	__ATOMIC_FILE,
	__VOLATILE_FILE,
	__MISC_FILE,
};

struct last_io_info {
	int major, minor;
	pid_t pid;
	enum file_type type;
	struct f2fs_io_info fio;
	block_t len;
};

extern void f2fs_trace_pid(struct page *);
extern void f2fs_trace_ios(struct f2fs_io_info *, int);
extern void f2fs_build_trace_ios(void);
extern void f2fs_destroy_trace_ios(void);
#else
#define f2fs_trace_pid(p)
#define f2fs_trace_ios(i, n)
#define f2fs_build_trace_ios()
#define f2fs_destroy_trace_ios()

#endif
#endif /* __F2FS_TRACE_H__ */
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