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556637cdab
After the loop in walk_pte_range() pte might point to the first address after the pmd it walks. The pte_unmap() is then applied to something bad. Spotted by Roel Kluin and Andreas Schwab. Signed-off-by: Johannes Weiner <hannes@saeurebad.de> Cc: Roel Kluin <12o3l@tiscali.nl> Cc: Andreas Schwab <schwab@suse.de> Acked-by: Matt Mackall <mpm@selenic.com> Acked-by: Mikael Pettersson <mikpe@it.uu.se> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
135 lines
3.4 KiB
C
135 lines
3.4 KiB
C
#include <linux/mm.h>
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#include <linux/highmem.h>
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#include <linux/sched.h>
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static int walk_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
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const struct mm_walk *walk, void *private)
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{
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pte_t *pte;
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int err = 0;
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pte = pte_offset_map(pmd, addr);
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for (;;) {
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err = walk->pte_entry(pte, addr, addr + PAGE_SIZE, private);
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if (err)
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break;
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addr += PAGE_SIZE;
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if (addr == end)
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break;
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pte++;
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}
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pte_unmap(pte);
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return err;
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}
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static int walk_pmd_range(pud_t *pud, unsigned long addr, unsigned long end,
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const struct mm_walk *walk, void *private)
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{
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pmd_t *pmd;
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unsigned long next;
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int err = 0;
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pmd = pmd_offset(pud, addr);
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do {
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next = pmd_addr_end(addr, end);
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if (pmd_none_or_clear_bad(pmd)) {
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if (walk->pte_hole)
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err = walk->pte_hole(addr, next, private);
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if (err)
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break;
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continue;
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}
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if (walk->pmd_entry)
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err = walk->pmd_entry(pmd, addr, next, private);
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if (!err && walk->pte_entry)
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err = walk_pte_range(pmd, addr, next, walk, private);
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if (err)
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break;
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} while (pmd++, addr = next, addr != end);
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return err;
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}
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static int walk_pud_range(pgd_t *pgd, unsigned long addr, unsigned long end,
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const struct mm_walk *walk, void *private)
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{
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pud_t *pud;
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unsigned long next;
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int err = 0;
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pud = pud_offset(pgd, addr);
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do {
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next = pud_addr_end(addr, end);
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if (pud_none_or_clear_bad(pud)) {
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if (walk->pte_hole)
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err = walk->pte_hole(addr, next, private);
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if (err)
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break;
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continue;
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}
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if (walk->pud_entry)
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err = walk->pud_entry(pud, addr, next, private);
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if (!err && (walk->pmd_entry || walk->pte_entry))
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err = walk_pmd_range(pud, addr, next, walk, private);
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if (err)
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break;
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} while (pud++, addr = next, addr != end);
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return err;
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}
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/**
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* walk_page_range - walk a memory map's page tables with a callback
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* @mm: memory map to walk
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* @addr: starting address
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* @end: ending address
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* @walk: set of callbacks to invoke for each level of the tree
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* @private: private data passed to the callback function
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*
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* Recursively walk the page table for the memory area in a VMA,
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* calling supplied callbacks. Callbacks are called in-order (first
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* PGD, first PUD, first PMD, first PTE, second PTE... second PMD,
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* etc.). If lower-level callbacks are omitted, walking depth is reduced.
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*
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* Each callback receives an entry pointer, the start and end of the
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* associated range, and a caller-supplied private data pointer.
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*
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* No locks are taken, but the bottom level iterator will map PTE
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* directories from highmem if necessary.
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*
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* If any callback returns a non-zero value, the walk is aborted and
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* the return value is propagated back to the caller. Otherwise 0 is returned.
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*/
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int walk_page_range(const struct mm_struct *mm,
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unsigned long addr, unsigned long end,
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const struct mm_walk *walk, void *private)
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{
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pgd_t *pgd;
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unsigned long next;
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int err = 0;
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if (addr >= end)
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return err;
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pgd = pgd_offset(mm, addr);
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do {
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next = pgd_addr_end(addr, end);
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if (pgd_none_or_clear_bad(pgd)) {
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if (walk->pte_hole)
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err = walk->pte_hole(addr, next, private);
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if (err)
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break;
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continue;
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}
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if (walk->pgd_entry)
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err = walk->pgd_entry(pgd, addr, next, private);
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if (!err &&
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(walk->pud_entry || walk->pmd_entry || walk->pte_entry))
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err = walk_pud_range(pgd, addr, next, walk, private);
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if (err)
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break;
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} while (pgd++, addr = next, addr != end);
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return err;
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}
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