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git.proxmox.com Git - mirror_ubuntu-jammy-kernel.git/blob - mm/debug-pagealloc.c
1 #include <linux/kernel.h>
3 #include <linux/page-debug-flags.h>
4 #include <linux/poison.h>
6 static inline void set_page_poison(struct page
*page
)
8 __set_bit(PAGE_DEBUG_FLAG_POISON
, &page
->debug_flags
);
11 static inline void clear_page_poison(struct page
*page
)
13 __clear_bit(PAGE_DEBUG_FLAG_POISON
, &page
->debug_flags
);
16 static inline bool page_poison(struct page
*page
)
18 return test_bit(PAGE_DEBUG_FLAG_POISON
, &page
->debug_flags
);
21 static void poison_highpage(struct page
*page
)
24 * Page poisoning for highmem pages is not implemented.
26 * This can be called from interrupt contexts.
27 * So we need to create a new kmap_atomic slot for this
28 * application and it will need interrupt protection.
32 static void poison_page(struct page
*page
)
36 if (PageHighMem(page
)) {
37 poison_highpage(page
);
40 set_page_poison(page
);
41 addr
= page_address(page
);
42 memset(addr
, PAGE_POISON
, PAGE_SIZE
);
45 static void poison_pages(struct page
*page
, int n
)
49 for (i
= 0; i
< n
; i
++)
50 poison_page(page
+ i
);
53 static bool single_bit_flip(unsigned char a
, unsigned char b
)
55 unsigned char error
= a
^ b
;
57 return error
&& !(error
& (error
- 1));
60 static void check_poison_mem(unsigned char *mem
, size_t bytes
)
65 for (start
= mem
; start
< mem
+ bytes
; start
++) {
66 if (*start
!= PAGE_POISON
)
69 if (start
== mem
+ bytes
)
72 for (end
= mem
+ bytes
- 1; end
> start
; end
--) {
73 if (*end
!= PAGE_POISON
)
77 if (!printk_ratelimit())
79 else if (start
== end
&& single_bit_flip(*start
, PAGE_POISON
))
80 printk(KERN_ERR
"pagealloc: single bit error\n");
82 printk(KERN_ERR
"pagealloc: memory corruption\n");
84 print_hex_dump(KERN_ERR
, "", DUMP_PREFIX_ADDRESS
, 16, 1, start
,
89 static void unpoison_highpage(struct page
*page
)
92 * See comment in poison_highpage().
93 * Highmem pages should not be poisoned for now
95 BUG_ON(page_poison(page
));
98 static void unpoison_page(struct page
*page
)
100 if (PageHighMem(page
)) {
101 unpoison_highpage(page
);
104 if (page_poison(page
)) {
105 void *addr
= page_address(page
);
107 check_poison_mem(addr
, PAGE_SIZE
);
108 clear_page_poison(page
);
112 static void unpoison_pages(struct page
*page
, int n
)
116 for (i
= 0; i
< n
; i
++)
117 unpoison_page(page
+ i
);
120 void kernel_map_pages(struct page
*page
, int numpages
, int enable
)
122 if (!debug_pagealloc_enabled
)
126 unpoison_pages(page
, numpages
);
128 poison_pages(page
, numpages
);