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106 lines
2.5 KiB
106 lines
2.5 KiB
// SPDX-License-Identifier: GPL-2.0 |
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#include <linux/kernel.h> |
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#include <linux/string.h> |
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#include <linux/mm.h> |
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#include <linux/mmdebug.h> |
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#include <linux/highmem.h> |
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#include <linux/page_ext.h> |
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#include <linux/poison.h> |
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#include <linux/ratelimit.h> |
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#include <linux/kasan.h> |
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bool _page_poisoning_enabled_early; |
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EXPORT_SYMBOL(_page_poisoning_enabled_early); |
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DEFINE_STATIC_KEY_FALSE(_page_poisoning_enabled); |
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EXPORT_SYMBOL(_page_poisoning_enabled); |
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static int __init early_page_poison_param(char *buf) |
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{ |
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return kstrtobool(buf, &_page_poisoning_enabled_early); |
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} |
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early_param("page_poison", early_page_poison_param); |
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static void poison_page(struct page *page) |
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{ |
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void *addr = kmap_atomic(page); |
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/* KASAN still think the page is in-use, so skip it. */ |
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kasan_disable_current(); |
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memset(kasan_reset_tag(addr), PAGE_POISON, PAGE_SIZE); |
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kasan_enable_current(); |
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kunmap_atomic(addr); |
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} |
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void __kernel_poison_pages(struct page *page, int n) |
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{ |
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int i; |
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for (i = 0; i < n; i++) |
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poison_page(page + i); |
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} |
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static bool single_bit_flip(unsigned char a, unsigned char b) |
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{ |
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unsigned char error = a ^ b; |
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return error && !(error & (error - 1)); |
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} |
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static void check_poison_mem(struct page *page, unsigned char *mem, size_t bytes) |
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{ |
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static DEFINE_RATELIMIT_STATE(ratelimit, 5 * HZ, 10); |
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unsigned char *start; |
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unsigned char *end; |
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start = memchr_inv(mem, PAGE_POISON, bytes); |
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if (!start) |
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return; |
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for (end = mem + bytes - 1; end > start; end--) { |
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if (*end != PAGE_POISON) |
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break; |
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} |
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if (!__ratelimit(&ratelimit)) |
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return; |
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else if (start == end && single_bit_flip(*start, PAGE_POISON)) |
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pr_err("pagealloc: single bit error\n"); |
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else |
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pr_err("pagealloc: memory corruption\n"); |
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print_hex_dump(KERN_ERR, "", DUMP_PREFIX_ADDRESS, 16, 1, start, |
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end - start + 1, 1); |
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dump_stack(); |
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dump_page(page, "pagealloc: corrupted page details"); |
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} |
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static void unpoison_page(struct page *page) |
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{ |
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void *addr; |
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addr = kmap_atomic(page); |
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kasan_disable_current(); |
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/* |
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* Page poisoning when enabled poisons each and every page |
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* that is freed to buddy. Thus no extra check is done to |
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* see if a page was poisoned. |
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*/ |
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check_poison_mem(page, kasan_reset_tag(addr), PAGE_SIZE); |
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kasan_enable_current(); |
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kunmap_atomic(addr); |
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} |
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void __kernel_unpoison_pages(struct page *page, int n) |
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{ |
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int i; |
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for (i = 0; i < n; i++) |
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unpoison_page(page + i); |
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} |
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#ifndef CONFIG_ARCH_SUPPORTS_DEBUG_PAGEALLOC |
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void __kernel_map_pages(struct page *page, int numpages, int enable) |
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{ |
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/* This function does nothing, all work is done via poison pages */ |
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} |
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#endif
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