diff options
Diffstat (limited to 'arch/x86/kernel/crash_dump_32.c')
| -rw-r--r-- | arch/x86/kernel/crash_dump_32.c | 28 |
1 files changed, 24 insertions, 4 deletions
diff --git a/arch/x86/kernel/crash_dump_32.c b/arch/x86/kernel/crash_dump_32.c index 72d0c56c1b4..11891ca7b71 100644 --- a/arch/x86/kernel/crash_dump_32.c +++ b/arch/x86/kernel/crash_dump_32.c @@ -5,6 +5,7 @@ * Copyright (C) IBM Corporation, 2004. All rights reserved */ +#include <linux/slab.h> #include <linux/errno.h> #include <linux/highmem.h> #include <linux/crash_dump.h> @@ -13,6 +14,22 @@ static void *kdump_buf_page; +static inline bool is_crashed_pfn_valid(unsigned long pfn) +{ +#ifndef CONFIG_X86_PAE + /* + * non-PAE kdump kernel executed from a PAE one will crop high pte + * bits and poke unwanted space counting again from address 0, we + * don't want that. pte must fit into unsigned long. In fact the + * test checks high 12 bits for being zero (pfn will be shifted left + * by PAGE_SHIFT). + */ + return pte_pfn(pfn_pte(pfn, __pgprot(0))) == pfn; +#else + return true; +#endif +} + /** * copy_oldmem_page - copy one page from "oldmem" * @pfn: page frame number to be copied @@ -38,20 +55,23 @@ ssize_t copy_oldmem_page(unsigned long pfn, char *buf, if (!csize) return 0; - vaddr = kmap_atomic_pfn(pfn, KM_PTE0); + if (!is_crashed_pfn_valid(pfn)) + return -EFAULT; + + vaddr = kmap_atomic_pfn(pfn); if (!userbuf) { memcpy(buf, (vaddr + offset), csize); - kunmap_atomic(vaddr, KM_PTE0); + kunmap_atomic(vaddr); } else { if (!kdump_buf_page) { printk(KERN_WARNING "Kdump: Kdump buffer page not" " allocated\n"); - kunmap_atomic(vaddr, KM_PTE0); + kunmap_atomic(vaddr); return -EFAULT; } copy_page(kdump_buf_page, vaddr); - kunmap_atomic(vaddr, KM_PTE0); + kunmap_atomic(vaddr); if (copy_to_user(buf, (kdump_buf_page + offset), csize)) return -EFAULT; } |