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  1. PO
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    <p>Well, I found that similar function is implemented in <code>KSplice</code> project and here is it:</p> <pre><code>/* * map_writable creates a shadow page mapping of the range * [addr, addr + len) so that we can write to code mapped read-only. * * It is similar to a generalized version of x86's text_poke. But * because one cannot use vmalloc/vfree() inside stop_machine, we use * map_writable to map the pages before stop_machine, then use the * mapping inside stop_machine, and unmap the pages afterwards. */ static void *map_writable(void *addr, size_t len) { void *vaddr; int nr_pages = DIV_ROUND_UP(offset_in_page(addr) + len, PAGE_SIZE); struct page **pages = kmalloc(nr_pages * sizeof(*pages), GFP_KERNEL); void *page_addr = (void *)((unsigned long)addr &amp; PAGE_MASK); int i; if (pages == NULL) return NULL; for (i = 0; i &lt; nr_pages; i++) { if (__module_address((unsigned long)page_addr) == NULL) { #if LINUX_VERSION_CODE &gt;= KERNEL_VERSION(2,6,22) || !defined(CONFIG_X86_64) pages[i] = virt_to_page(page_addr); #else /* LINUX_VERSION_CODE &lt; &amp;&amp; CONFIG_X86_64 */ /* e3ebadd95cb621e2c7436f3d3646447ac9d5c16d was after 2.6.21 * This works around a broken virt_to_page() from the RHEL 5 backport * of x86-64 relocatable kernel support. */ pages[i] = pfn_to_page(__pa_symbol(page_addr) &gt;&gt; PAGE_SHIFT); #endif /* LINUX_VERSION_CODE || !CONFIG_X86_64 */ WARN_ON(!PageReserved(pages[i])); } else { pages[i] = vmalloc_to_page(addr); } if (pages[i] == NULL) { kfree(pages); return NULL; } page_addr += PAGE_SIZE; } vaddr = vmap(pages, nr_pages, VM_MAP, PAGE_KERNEL); kfree(pages); if (vaddr == NULL) return NULL; return vaddr + offset_in_page(addr); } </code></pre> <p>So, as it comes there is a different handling of kernel's and module's memory. If the page is not belongs to any module then <code>vmalloc_to_page</code> rather then <code>virt_to_phys</code> used. I'll check if it helps and post the result later.</p>
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    1. POIs it possible to vmap kernel module's memory?
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    1. USIlya Matveychikov
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    1. POIs it possible to vmap kernel module's memory?
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    1. COWell, it works. But it seems that there is a bug in this function with `vmalloc_to_page(addr)`. There probably must be `vmalloc_to_page(page_addr)`.
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      1. USIlya Matveychikov
 

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