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genalloc improperly stores the sizes of freed chunks, allocates overlapping memory regions, and oopses after its in-band data is overwritten. Signed-off-by: Chris Humbert <mahadri-kernel@drigon.com> Cc: Jes Sorensen <jes@trained-monkey.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
186 lines
4.4 KiB
C
186 lines
4.4 KiB
C
/*
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* Basic general purpose allocator for managing special purpose memory
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* not managed by the regular kmalloc/kfree interface.
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* Uses for this includes on-device special memory, uncached memory
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* etc.
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*
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* This code is based on the buddy allocator found in the sym53c8xx_2
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* driver Copyright (C) 1999-2001 Gerard Roudier <groudier@free.fr>,
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* and adapted for general purpose use.
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*
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* Copyright 2005 (C) Jes Sorensen <jes@trained-monkey.org>
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*
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* This source code is licensed under the GNU General Public License,
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* Version 2. See the file COPYING for more details.
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*/
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#include <linux/module.h>
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#include <linux/stddef.h>
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#include <linux/kernel.h>
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#include <linux/string.h>
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#include <linux/slab.h>
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#include <linux/init.h>
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#include <linux/mm.h>
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#include <linux/spinlock.h>
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#include <linux/genalloc.h>
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#include <asm/page.h>
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struct gen_pool *gen_pool_create(int nr_chunks, int max_chunk_shift,
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unsigned long (*fp)(struct gen_pool *),
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unsigned long data)
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{
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struct gen_pool *poolp;
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unsigned long tmp;
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int i;
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/*
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* This is really an arbitrary limit, +10 is enough for
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* IA64_GRANULE_SHIFT, aka 16MB. If anyone needs a large limit
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* this can be increased without problems.
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*/
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if ((max_chunk_shift > (PAGE_SHIFT + 10)) ||
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((max_chunk_shift < ALLOC_MIN_SHIFT) && max_chunk_shift))
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return NULL;
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if (!max_chunk_shift)
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max_chunk_shift = PAGE_SHIFT;
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poolp = kmalloc(sizeof(struct gen_pool), GFP_KERNEL);
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if (!poolp)
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return NULL;
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memset(poolp, 0, sizeof(struct gen_pool));
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poolp->h = kmalloc(sizeof(struct gen_pool_link) *
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(max_chunk_shift - ALLOC_MIN_SHIFT + 1),
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GFP_KERNEL);
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if (!poolp->h) {
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printk(KERN_WARNING "gen_pool_alloc() failed to allocate\n");
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kfree(poolp);
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return NULL;
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}
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memset(poolp->h, 0, sizeof(struct gen_pool_link) *
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(max_chunk_shift - ALLOC_MIN_SHIFT + 1));
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spin_lock_init(&poolp->lock);
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poolp->get_new_chunk = fp;
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poolp->max_chunk_shift = max_chunk_shift;
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poolp->private = data;
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for (i = 0; i < nr_chunks; i++) {
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tmp = poolp->get_new_chunk(poolp);
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printk(KERN_INFO "allocated %lx\n", tmp);
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if (!tmp)
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break;
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gen_pool_free(poolp, tmp, (1 << poolp->max_chunk_shift));
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}
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return poolp;
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}
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EXPORT_SYMBOL(gen_pool_create);
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/*
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* Simple power of two buddy-like generic allocator.
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* Provides naturally aligned memory chunks.
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*/
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unsigned long gen_pool_alloc(struct gen_pool *poolp, int size)
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{
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int j, i, s, max_chunk_size;
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unsigned long a, flags;
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struct gen_pool_link *h = poolp->h;
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max_chunk_size = 1 << poolp->max_chunk_shift;
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if (size > max_chunk_size)
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return 0;
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size = max(size, 1 << ALLOC_MIN_SHIFT);
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i = fls(size - 1);
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s = 1 << i;
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j = i -= ALLOC_MIN_SHIFT;
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spin_lock_irqsave(&poolp->lock, flags);
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while (!h[j].next) {
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if (s == max_chunk_size) {
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struct gen_pool_link *ptr;
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spin_unlock_irqrestore(&poolp->lock, flags);
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ptr = (struct gen_pool_link *)poolp->get_new_chunk(poolp);
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spin_lock_irqsave(&poolp->lock, flags);
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h[j].next = ptr;
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if (h[j].next)
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h[j].next->next = NULL;
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break;
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}
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j++;
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s <<= 1;
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}
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a = (unsigned long) h[j].next;
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if (a) {
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h[j].next = h[j].next->next;
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/*
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* This should be split into a seperate function doing
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* the chunk split in order to support custom
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* handling memory not physically accessible by host
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*/
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while (j > i) {
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j -= 1;
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s >>= 1;
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h[j].next = (struct gen_pool_link *) (a + s);
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h[j].next->next = NULL;
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}
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}
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spin_unlock_irqrestore(&poolp->lock, flags);
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return a;
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}
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EXPORT_SYMBOL(gen_pool_alloc);
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/*
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* Counter-part of the generic allocator.
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*/
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void gen_pool_free(struct gen_pool *poolp, unsigned long ptr, int size)
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{
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struct gen_pool_link *q;
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struct gen_pool_link *h = poolp->h;
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unsigned long a, b, flags;
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int i, s, max_chunk_size;
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max_chunk_size = 1 << poolp->max_chunk_shift;
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if (size > max_chunk_size)
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return;
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size = max(size, 1 << ALLOC_MIN_SHIFT);
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i = fls(size - 1);
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s = 1 << i;
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i -= ALLOC_MIN_SHIFT;
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a = ptr;
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spin_lock_irqsave(&poolp->lock, flags);
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while (1) {
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if (s == max_chunk_size) {
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((struct gen_pool_link *)a)->next = h[i].next;
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h[i].next = (struct gen_pool_link *)a;
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break;
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}
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b = a ^ s;
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q = &h[i];
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while (q->next && q->next != (struct gen_pool_link *)b)
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q = q->next;
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if (!q->next) {
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((struct gen_pool_link *)a)->next = h[i].next;
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h[i].next = (struct gen_pool_link *)a;
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break;
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}
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q->next = q->next->next;
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a = a & b;
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s <<= 1;
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i++;
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}
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spin_unlock_irqrestore(&poolp->lock, flags);
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}
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EXPORT_SYMBOL(gen_pool_free);
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