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![Clement Calmels](/assets/img/avatar_default.png)
This addresses http://bugzilla.kernel.org/show_bug.cgi?id=11318 In function show_map (file: fs/proc/task_mmu.c), if vma->vm_pgoff > 2^20 than (vma->vm_pgoff << PAGE_SIZE) is greater than 2^32 (with PAGE_SIZE equal to 4096 (i.e. 2^12). The next seq_printf use an unsigned long for the conversion of (vma->vm_pgoff << PAGE_SIZE), as a result the offset value displayed in /proc/self/maps is truncated if the page offset is greater than 2^20. A test that shows this issue: #define _GNU_SOURCE #include <sys/types.h> #include <sys/stat.h> #include <sys/mman.h> #include <stdlib.h> #include <stdio.h> #include <fcntl.h> #include <unistd.h> #include <string.h> #define PAGE_SIZE (getpagesize()) #if __i386__ # define U64_STR "%llx" #elif __x86_64 # define U64_STR "%lx" #else # error "Architecture Unsupported" #endif int main(int argc, char *argv[]) { int fd; char *addr; off64_t offset = 0x10000000; char *filename = "/dev/zero"; fd = open(filename, O_RDONLY); if (fd < 0) { perror("open"); return 1; } offset *= 0x10; printf("offset = " U64_STR "\n", offset); addr = (char*)mmap64(NULL, PAGE_SIZE, PROT_READ, MAP_PRIVATE, fd, offset); if ((void*)addr == MAP_FAILED) { perror("mmap64"); return 1; } { FILE *fmaps; char *line = NULL; size_t len = 0; ssize_t read; size_t filename_len = strlen(filename); fmaps = fopen("/proc/self/maps", "r"); if (!fmaps) { perror("fopen"); return 1; } while ((read = getline(&line, &len, fmaps)) != -1) { if ((read > filename_len + 1) && (strncmp(&line[read - filename_len - 1], filename, filename_len) == 0)) printf("%s", line); } if (line) free(line); fclose(fmaps); } close(fd); return 0; } [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Clement Calmels <cboulte@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
144 lines
3.3 KiB
C
144 lines
3.3 KiB
C
/* nommu.c: mmu-less memory info files
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*
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* Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/errno.h>
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#include <linux/time.h>
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#include <linux/kernel.h>
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#include <linux/string.h>
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#include <linux/mman.h>
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#include <linux/proc_fs.h>
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#include <linux/mm.h>
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#include <linux/mmzone.h>
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#include <linux/pagemap.h>
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#include <linux/swap.h>
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#include <linux/slab.h>
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#include <linux/smp.h>
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#include <linux/seq_file.h>
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#include <linux/hugetlb.h>
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#include <linux/vmalloc.h>
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#include <asm/uaccess.h>
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#include <asm/pgtable.h>
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#include <asm/tlb.h>
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#include <asm/div64.h>
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#include "internal.h"
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/*
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* display a single VMA to a sequenced file
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*/
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int nommu_vma_show(struct seq_file *m, struct vm_area_struct *vma)
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{
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unsigned long ino = 0;
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struct file *file;
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dev_t dev = 0;
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int flags, len;
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flags = vma->vm_flags;
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file = vma->vm_file;
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if (file) {
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struct inode *inode = vma->vm_file->f_path.dentry->d_inode;
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dev = inode->i_sb->s_dev;
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ino = inode->i_ino;
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}
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seq_printf(m,
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"%08lx-%08lx %c%c%c%c %08llx %02x:%02x %lu %n",
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vma->vm_start,
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vma->vm_end,
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flags & VM_READ ? 'r' : '-',
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flags & VM_WRITE ? 'w' : '-',
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flags & VM_EXEC ? 'x' : '-',
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flags & VM_MAYSHARE ? flags & VM_SHARED ? 'S' : 's' : 'p',
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((loff_t)vma->vm_pgoff) << PAGE_SHIFT,
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MAJOR(dev), MINOR(dev), ino, &len);
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if (file) {
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len = 25 + sizeof(void *) * 6 - len;
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if (len < 1)
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len = 1;
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seq_printf(m, "%*c", len, ' ');
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seq_path(m, &file->f_path, "");
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}
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seq_putc(m, '\n');
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return 0;
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}
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/*
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* display a list of all the VMAs the kernel knows about
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* - nommu kernals have a single flat list
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*/
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static int nommu_vma_list_show(struct seq_file *m, void *v)
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{
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struct vm_area_struct *vma;
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vma = rb_entry((struct rb_node *) v, struct vm_area_struct, vm_rb);
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return nommu_vma_show(m, vma);
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}
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static void *nommu_vma_list_start(struct seq_file *m, loff_t *_pos)
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{
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struct rb_node *_rb;
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loff_t pos = *_pos;
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void *next = NULL;
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down_read(&nommu_vma_sem);
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for (_rb = rb_first(&nommu_vma_tree); _rb; _rb = rb_next(_rb)) {
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if (pos == 0) {
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next = _rb;
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break;
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}
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pos--;
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}
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return next;
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}
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static void nommu_vma_list_stop(struct seq_file *m, void *v)
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{
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up_read(&nommu_vma_sem);
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}
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static void *nommu_vma_list_next(struct seq_file *m, void *v, loff_t *pos)
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{
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(*pos)++;
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return rb_next((struct rb_node *) v);
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}
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static const struct seq_operations proc_nommu_vma_list_seqop = {
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.start = nommu_vma_list_start,
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.next = nommu_vma_list_next,
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.stop = nommu_vma_list_stop,
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.show = nommu_vma_list_show
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};
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static int proc_nommu_vma_list_open(struct inode *inode, struct file *file)
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{
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return seq_open(file, &proc_nommu_vma_list_seqop);
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}
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static const struct file_operations proc_nommu_vma_list_operations = {
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.open = proc_nommu_vma_list_open,
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.read = seq_read,
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.llseek = seq_lseek,
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.release = seq_release,
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};
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static int __init proc_nommu_init(void)
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{
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proc_create("maps", S_IRUGO, NULL, &proc_nommu_vma_list_operations);
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return 0;
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}
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module_init(proc_nommu_init);
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