f5252e009d
The /proc/vmallocinfo shows information about vmalloc allocations in vmlist that is a linklist of vm_struct. It, however, may access pages field of vm_struct where a page was not allocated. This results in a null pointer access and leads to a kernel panic. Why this happens: In __vmalloc_node_range() called from vmalloc(), newly allocated vm_struct is added to vmlist at __get_vm_area_node() and then, some fields of vm_struct such as nr_pages and pages are set at __vmalloc_area_node(). In other words, it is added to vmlist before it is fully initialized. At the same time, when the /proc/vmallocinfo is read, it accesses the pages field of vm_struct according to the nr_pages field at show_numa_info(). Thus, a null pointer access happens. The patch adds the newly allocated vm_struct to the vmlist *after* it is fully initialized. So, it can avoid accessing the pages field with unallocated page when show_numa_info() is called. Signed-off-by: Mitsuo Hayasaka <mitsuo.hayasaka.hu@hitachi.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: David Rientjes <rientjes@google.com> Cc: Namhyung Kim <namhyung@gmail.com> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Cc: <stable@kernel.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
159 lines
4.7 KiB
C
159 lines
4.7 KiB
C
#ifndef _LINUX_VMALLOC_H
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#define _LINUX_VMALLOC_H
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#include <linux/spinlock.h>
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#include <linux/init.h>
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#include <asm/page.h> /* pgprot_t */
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struct vm_area_struct; /* vma defining user mapping in mm_types.h */
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/* bits in flags of vmalloc's vm_struct below */
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#define VM_IOREMAP 0x00000001 /* ioremap() and friends */
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#define VM_ALLOC 0x00000002 /* vmalloc() */
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#define VM_MAP 0x00000004 /* vmap()ed pages */
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#define VM_USERMAP 0x00000008 /* suitable for remap_vmalloc_range */
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#define VM_VPAGES 0x00000010 /* buffer for pages was vmalloc'ed */
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#define VM_UNLIST 0x00000020 /* vm_struct is not listed in vmlist */
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/* bits [20..32] reserved for arch specific ioremap internals */
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/*
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* Maximum alignment for ioremap() regions.
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* Can be overriden by arch-specific value.
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*/
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#ifndef IOREMAP_MAX_ORDER
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#define IOREMAP_MAX_ORDER (7 + PAGE_SHIFT) /* 128 pages */
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#endif
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struct vm_struct {
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struct vm_struct *next;
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void *addr;
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unsigned long size;
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unsigned long flags;
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struct page **pages;
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unsigned int nr_pages;
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phys_addr_t phys_addr;
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void *caller;
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};
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/*
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* Highlevel APIs for driver use
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*/
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extern void vm_unmap_ram(const void *mem, unsigned int count);
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extern void *vm_map_ram(struct page **pages, unsigned int count,
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int node, pgprot_t prot);
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extern void vm_unmap_aliases(void);
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#ifdef CONFIG_MMU
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extern void __init vmalloc_init(void);
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#else
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static inline void vmalloc_init(void)
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{
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}
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#endif
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extern void *vmalloc(unsigned long size);
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extern void *vzalloc(unsigned long size);
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extern void *vmalloc_user(unsigned long size);
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extern void *vmalloc_node(unsigned long size, int node);
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extern void *vzalloc_node(unsigned long size, int node);
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extern void *vmalloc_exec(unsigned long size);
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extern void *vmalloc_32(unsigned long size);
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extern void *vmalloc_32_user(unsigned long size);
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extern void *__vmalloc(unsigned long size, gfp_t gfp_mask, pgprot_t prot);
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extern void *__vmalloc_node_range(unsigned long size, unsigned long align,
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unsigned long start, unsigned long end, gfp_t gfp_mask,
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pgprot_t prot, int node, void *caller);
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extern void vfree(const void *addr);
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extern void *vmap(struct page **pages, unsigned int count,
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unsigned long flags, pgprot_t prot);
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extern void vunmap(const void *addr);
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extern int remap_vmalloc_range(struct vm_area_struct *vma, void *addr,
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unsigned long pgoff);
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void vmalloc_sync_all(void);
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/*
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* Lowlevel-APIs (not for driver use!)
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*/
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static inline size_t get_vm_area_size(const struct vm_struct *area)
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{
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/* return actual size without guard page */
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return area->size - PAGE_SIZE;
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}
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extern struct vm_struct *get_vm_area(unsigned long size, unsigned long flags);
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extern struct vm_struct *get_vm_area_caller(unsigned long size,
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unsigned long flags, void *caller);
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extern struct vm_struct *__get_vm_area(unsigned long size, unsigned long flags,
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unsigned long start, unsigned long end);
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extern struct vm_struct *__get_vm_area_caller(unsigned long size,
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unsigned long flags,
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unsigned long start, unsigned long end,
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void *caller);
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extern struct vm_struct *remove_vm_area(const void *addr);
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extern int map_vm_area(struct vm_struct *area, pgprot_t prot,
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struct page ***pages);
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#ifdef CONFIG_MMU
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extern int map_kernel_range_noflush(unsigned long start, unsigned long size,
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pgprot_t prot, struct page **pages);
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extern void unmap_kernel_range_noflush(unsigned long addr, unsigned long size);
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extern void unmap_kernel_range(unsigned long addr, unsigned long size);
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#else
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static inline int
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map_kernel_range_noflush(unsigned long start, unsigned long size,
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pgprot_t prot, struct page **pages)
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{
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return size >> PAGE_SHIFT;
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}
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static inline void
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unmap_kernel_range_noflush(unsigned long addr, unsigned long size)
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{
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}
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static inline void
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unmap_kernel_range(unsigned long addr, unsigned long size)
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{
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}
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#endif
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/* Allocate/destroy a 'vmalloc' VM area. */
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extern struct vm_struct *alloc_vm_area(size_t size);
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extern void free_vm_area(struct vm_struct *area);
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/* for /dev/kmem */
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extern long vread(char *buf, char *addr, unsigned long count);
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extern long vwrite(char *buf, char *addr, unsigned long count);
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/*
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* Internals. Dont't use..
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*/
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extern rwlock_t vmlist_lock;
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extern struct vm_struct *vmlist;
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extern __init void vm_area_register_early(struct vm_struct *vm, size_t align);
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#ifdef CONFIG_SMP
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# ifdef CONFIG_MMU
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struct vm_struct **pcpu_get_vm_areas(const unsigned long *offsets,
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const size_t *sizes, int nr_vms,
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size_t align);
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void pcpu_free_vm_areas(struct vm_struct **vms, int nr_vms);
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# else
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static inline struct vm_struct **
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pcpu_get_vm_areas(const unsigned long *offsets,
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const size_t *sizes, int nr_vms,
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size_t align)
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{
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return NULL;
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}
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static inline void
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pcpu_free_vm_areas(struct vm_struct **vms, int nr_vms)
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{
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}
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# endif
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#endif
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#endif /* _LINUX_VMALLOC_H */
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