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#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/highmem.h>
#include <linux/page-debug-flags.h>
#include <linux/poison.h>
#include <linux/ratelimit.h>
#include <linux/stacktrace.h>
#include <linux/sched.h>
#ifndef mark_addr_rdonly
#define mark_addr_rdonly(a)
#endif
#ifndef mark_addr_rdwrite
#define mark_addr_rdwrite(a)
#endif
#ifdef CONFIG_HTC_DEBUG_PAGE_USER_TRACE
#define page_to_trace(page, free) \
(free ? \
&page->trace_free : \
&page->trace_alloc)
#define page_to_entries_size(page, free) \
(free ? \
ARRAY_SIZE(page->trace_free.entries) : \
ARRAY_SIZE(page->trace_alloc.entries))
static
void htc_trace_pages_user(struct page *page, int numpages, int free)
{
struct page_user_trace* user_trace;
struct stack_trace trace;
unsigned long* entries;
int nr_entries;
if (unlikely(!page))
return;
user_trace = page_to_trace(page, free);
entries = user_trace->entries;
nr_entries = page_to_entries_size(page, free);
user_trace->pid = current->pid;
user_trace->tgid = current->tgid;
memcpy(user_trace->comm, current->comm,
sizeof(user_trace->comm));
memcpy(user_trace->tgcomm, current->group_leader->comm,
sizeof(user_trace->comm));
if (unlikely(!nr_entries))
return;
memset(entries, 0, nr_entries * sizeof(*entries));
trace.max_entries = nr_entries;
trace.entries = entries;
trace.nr_entries = 0;
trace.skip = 5;
save_stack_trace(&trace);
for (; page++, numpages > 1; numpages--)
memcpy(page_to_trace(page, free), user_trace, sizeof(*user_trace));
}
static
void dump_page_user(struct page *page, int free)
{
struct page_user_trace* user_trace;
struct stack_trace trace;
user_trace = page_to_trace(page, free);
pr_warn("%s by process - %.*s pid=%d (tg: %.*s pid=%d)\n",
free ? "Free" : "Alloc",
(int) sizeof(user_trace->comm),
user_trace->comm,
user_trace->pid,
(int) sizeof(user_trace->tgcomm),
user_trace->tgcomm,
user_trace->tgid);
trace.nr_entries = page_to_entries_size(page, free);;
trace.entries = user_trace->entries;
pr_warn("Call trace:\n");
print_stack_trace(&trace, 0);
}
static
void htc_dump_page_user(struct page *page)
{
pr_warn("%s: check_poison_mem failed at page: %p\n",
__func__, page);
dump_page_user(page, 0);
dump_page_user(page, 1);
}
#else
static inline
void htc_trace_pages_user(struct page *page, int numpages, int free) { }
static inline
void htc_dump_page_user(struct page *page) { }
#endif /* CONFIG_HTC_DEBUG_PAGE_USER_TRACE */
static inline void set_page_poison(struct page *page)
{
__set_bit(PAGE_DEBUG_FLAG_POISON, &page->debug_flags);
}
static inline void clear_page_poison(struct page *page)
{
__clear_bit(PAGE_DEBUG_FLAG_POISON, &page->debug_flags);
}
static inline bool page_poison(struct page *page)
{
return test_bit(PAGE_DEBUG_FLAG_POISON, &page->debug_flags);
}
static void poison_page(struct page *page)
{
void *addr = kmap_atomic(page);
set_page_poison(page);
memset(addr, PAGE_POISON, PAGE_SIZE);
mark_addr_rdonly(addr);
kunmap_atomic(addr);
}
static void 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(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))
printk(KERN_ERR "pagealloc: single bit error\n");
else
printk(KERN_ERR "pagealloc: memory corruption\n");
print_hex_dump(KERN_ERR, "", DUMP_PREFIX_ADDRESS, 16, 1, start,
end - start + 1, 1);
htc_dump_page_user(kmap_to_page(mem));
BUG_ON(PANIC_CORRUPTION);
dump_stack();
}
static void unpoison_page(struct page *page)
{
void *addr;
if (!page_poison(page))
return;
addr = kmap_atomic(page);
check_poison_mem(addr, PAGE_SIZE);
mark_addr_rdwrite(addr);
clear_page_poison(page);
kunmap_atomic(addr);
}
static void unpoison_pages(struct page *page, int n)
{
int i;
for (i = 0; i < n; i++)
unpoison_page(page + i);
}
void kernel_map_pages(struct page *page, int numpages, int enable)
{
if (enable)
unpoison_pages(page, numpages);
else
poison_pages(page, numpages);
htc_trace_pages_user(page, numpages, !enable);
}
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