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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
commit | 2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch) | |
tree | 848558de17fb3008cdf4d861b01ac7781903ce39 /mm/page_poison.c | |
parent | Initial commit. (diff) | |
download | linux-upstream.tar.xz linux-upstream.zip |
Adding upstream version 6.1.76.upstream/6.1.76upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | mm/page_poison.c | 106 |
1 files changed, 106 insertions, 0 deletions
diff --git a/mm/page_poison.c b/mm/page_poison.c new file mode 100644 index 000000000..98438985e --- /dev/null +++ b/mm/page_poison.c @@ -0,0 +1,106 @@ +// SPDX-License-Identifier: GPL-2.0 +#include <linux/kernel.h> +#include <linux/string.h> +#include <linux/mm.h> +#include <linux/mmdebug.h> +#include <linux/highmem.h> +#include <linux/page_ext.h> +#include <linux/poison.h> +#include <linux/ratelimit.h> +#include <linux/kasan.h> + +bool _page_poisoning_enabled_early; +EXPORT_SYMBOL(_page_poisoning_enabled_early); +DEFINE_STATIC_KEY_FALSE(_page_poisoning_enabled); +EXPORT_SYMBOL(_page_poisoning_enabled); + +static int __init early_page_poison_param(char *buf) +{ + return kstrtobool(buf, &_page_poisoning_enabled_early); +} +early_param("page_poison", early_page_poison_param); + +static void poison_page(struct page *page) +{ + void *addr = kmap_atomic(page); + + /* KASAN still think the page is in-use, so skip it. */ + kasan_disable_current(); + memset(kasan_reset_tag(addr), PAGE_POISON, PAGE_SIZE); + kasan_enable_current(); + kunmap_atomic(addr); +} + +void __kernel_poison_pages(struct page *page, int n) +{ + int i; + + for (i = 0; i < n; i++) + poison_page(page + i); +} + +static bool single_bit_flip(unsigned char a, unsigned char b) +{ + unsigned char error = a ^ b; + + return error && !(error & (error - 1)); +} + +static void check_poison_mem(struct page *page, unsigned char *mem, size_t bytes) +{ + static DEFINE_RATELIMIT_STATE(ratelimit, 5 * HZ, 10); + unsigned char *start; + unsigned char *end; + + start = memchr_inv(mem, PAGE_POISON, bytes); + if (!start) + return; + + for (end = mem + bytes - 1; end > start; end--) { + if (*end != PAGE_POISON) + break; + } + + if (!__ratelimit(&ratelimit)) + return; + else if (start == end && single_bit_flip(*start, PAGE_POISON)) + pr_err("pagealloc: single bit error\n"); + else + pr_err("pagealloc: memory corruption\n"); + + print_hex_dump(KERN_ERR, "", DUMP_PREFIX_ADDRESS, 16, 1, start, + end - start + 1, 1); + dump_stack(); + dump_page(page, "pagealloc: corrupted page details"); +} + +static void unpoison_page(struct page *page) +{ + void *addr; + + addr = kmap_atomic(page); + kasan_disable_current(); + /* + * Page poisoning when enabled poisons each and every page + * that is freed to buddy. Thus no extra check is done to + * see if a page was poisoned. + */ + check_poison_mem(page, kasan_reset_tag(addr), PAGE_SIZE); + kasan_enable_current(); + kunmap_atomic(addr); +} + +void __kernel_unpoison_pages(struct page *page, int n) +{ + int i; + + for (i = 0; i < n; i++) + unpoison_page(page + i); +} + +#ifndef CONFIG_ARCH_SUPPORTS_DEBUG_PAGEALLOC +void __kernel_map_pages(struct page *page, int numpages, int enable) +{ + /* This function does nothing, all work is done via poison pages */ +} +#endif |