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authorKirill A. Shutemov <kirill.shutemov@linux.intel.com>2017-04-25 12:25:57 +0300
committerIngo Molnar <mingo@kernel.org>2017-04-26 08:26:43 +0200
commite6ab9c4d437764c7fb728d428dc9e717cdb183d0 (patch)
tree4cae14dfd336fb180108154065811653dcfe23f3 /arch/x86/mm
parent6dd29b3df975582ef429b5b93c899e6575785940 (diff)
x86/mm/64: Fix crash in remove_pagetable()
remove_pagetable() does page walk using p*d_page_vaddr() plus cast. It's not canonical approach -- we usually use p*d_offset() for that. It works fine as long as all page table levels are present. We broke the invariant by introducing folded p4d page table level. As result, remove_pagetable() interprets PMD as PUD and it leads to crash: BUG: unable to handle kernel paging request at ffff880300000000 IP: memchr_inv+0x60/0x110 PGD 317d067 P4D 317d067 PUD 3180067 PMD 33f102067 PTE 8000000300000060 Let's fix this by using p*d_offset() instead of p*d_page_vaddr() for page walk. Reported-by: Dan Williams <dan.j.williams@intel.com> Tested-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-mm@kvack.org Fixes: f2a6a7050109 ("x86: Convert the rest of the code to support p4d_t") Link: http://lkml.kernel.org/r/20170425092557.21852-1-kirill.shutemov@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/mm')
-rw-r--r--arch/x86/mm/init_64.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index a242139df8fe..745e5e183169 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -962,7 +962,7 @@ remove_pud_table(pud_t *pud_start, unsigned long addr, unsigned long end,
continue;
}
- pmd_base = (pmd_t *)pud_page_vaddr(*pud);
+ pmd_base = pmd_offset(pud, 0);
remove_pmd_table(pmd_base, addr, next, direct);
free_pmd_table(pmd_base, pud);
}
@@ -988,7 +988,7 @@ remove_p4d_table(p4d_t *p4d_start, unsigned long addr, unsigned long end,
BUILD_BUG_ON(p4d_large(*p4d));
- pud_base = (pud_t *)p4d_page_vaddr(*p4d);
+ pud_base = pud_offset(p4d, 0);
remove_pud_table(pud_base, addr, next, direct);
free_pud_table(pud_base, p4d);
}
@@ -1013,7 +1013,7 @@ remove_pagetable(unsigned long start, unsigned long end, bool direct)
if (!pgd_present(*pgd))
continue;
- p4d = (p4d_t *)pgd_page_vaddr(*pgd);
+ p4d = p4d_offset(pgd, 0);
remove_p4d_table(p4d, addr, next, direct);
}