vmcore: allocate buffer for ELF headers on page-size alignment

Allocate buffer for ELF headers on page-size aligned boudary to satisfy
mmap() requirement.  For this, __get_free_pages() is used instead of
kmalloc().

Also, later patch will decrease actually used buffer size for ELF headers,
so it's necessary to keep original buffer size and actually used buffer
size separately.  elfcorebuf_sz_orig keeps the original one and
elfcorebuf_sz the actually used one.

Signed-off-by: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>
Reviewed-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c
index 7d2dc4cd95e2c14da97509c1571de5cb28e66abc..17e2501151a232df8cfa6a3281bff5c9b84acf3e 100644 (file)
--- a/fs/proc/vmcore.c
+++ b/fs/proc/vmcore.c
@@ -31,6 +31,7 @@ static LIST_HEAD(vmcore_list);
 /* Stores the pointer to the buffer containing kernel elf core headers. */
 static char *elfcorebuf;
 static size_t elfcorebuf_sz;
+static size_t elfcorebuf_sz_orig;
 
 /* Total size of vmcore file. */
 static u64 vmcore_size;
@@ -608,13 +609,16 @@ static int __init parse_crash_elf64_headers(void)
 
        /* Read in all elf headers. */
        elfcorebuf_sz = sizeof(Elf64_Ehdr) + ehdr.e_phnum * sizeof(Elf64_Phdr);
-       elfcorebuf = kmalloc(elfcorebuf_sz, GFP_KERNEL);
+       elfcorebuf_sz_orig = elfcorebuf_sz;
+       elfcorebuf = (void *) __get_free_pages(GFP_KERNEL | __GFP_ZERO,
+                                              get_order(elfcorebuf_sz_orig));
        if (!elfcorebuf)
                return -ENOMEM;
        addr = elfcorehdr_addr;
        rc = read_from_oldmem(elfcorebuf, sizeof(Elf64_Ehdr), &addr, 0);
        if (rc < 0) {
-               kfree(elfcorebuf);
+               free_pages((unsigned long)elfcorebuf,
+                          get_order(elfcorebuf_sz_orig));
                return rc;
        }
        addr = elfcorehdr_addr + ehdr.e_phoff;
@@ -629,13 +633,15 @@ static int __init parse_crash_elf64_headers(void)
        /* Merge all PT_NOTE headers into one. */
        rc = merge_note_headers_elf64(elfcorebuf, &elfcorebuf_sz, &vmcore_list);
        if (rc) {
-               kfree(elfcorebuf);
+               free_pages((unsigned long)elfcorebuf,
+                          get_order(elfcorebuf_sz_orig));
                return rc;
        }
        rc = process_ptload_program_headers_elf64(elfcorebuf, elfcorebuf_sz,
                                                        &vmcore_list);
        if (rc) {
-               kfree(elfcorebuf);
+               free_pages((unsigned long)elfcorebuf,
+                          get_order(elfcorebuf_sz_orig));
                return rc;
        }
        set_vmcore_list_offsets_elf64(elfcorebuf, &vmcore_list);
@@ -671,7 +677,9 @@ static int __init parse_crash_elf32_headers(void)
 
        /* Read in all elf headers. */
        elfcorebuf_sz = sizeof(Elf32_Ehdr) + ehdr.e_phnum * sizeof(Elf32_Phdr);
-       elfcorebuf = kmalloc(elfcorebuf_sz, GFP_KERNEL);
+       elfcorebuf_sz_orig = elfcorebuf_sz;
+       elfcorebuf = (void *) __get_free_pages(GFP_KERNEL | __GFP_ZERO,
+                                              get_order(elfcorebuf_sz_orig));
        if (!elfcorebuf)
                return -ENOMEM;
        addr = elfcorehdr_addr;
@@ -684,7 +692,8 @@ static int __init parse_crash_elf32_headers(void)
        rc = read_from_oldmem(elfcorebuf + sizeof(Elf32_Ehdr),
                              ehdr.e_phnum * sizeof(Elf32_Phdr), &addr, 0);
        if (rc < 0) {
-               kfree(elfcorebuf);
+               free_pages((unsigned long)elfcorebuf,
+                          get_order(elfcorebuf_sz_orig));
                return rc;
        }
        ((Elf32_Ehdr *)elfcorebuf)->e_phoff = sizeof(Elf32_Ehdr);
@@ -692,13 +701,15 @@ static int __init parse_crash_elf32_headers(void)
        /* Merge all PT_NOTE headers into one. */
        rc = merge_note_headers_elf32(elfcorebuf, &elfcorebuf_sz, &vmcore_list);
        if (rc) {
-               kfree(elfcorebuf);
+               free_pages((unsigned long)elfcorebuf,
+                          get_order(elfcorebuf_sz_orig));
                return rc;
        }
        rc = process_ptload_program_headers_elf32(elfcorebuf, elfcorebuf_sz,
                                                                &vmcore_list);
        if (rc) {
-               kfree(elfcorebuf);
+               free_pages((unsigned long)elfcorebuf,
+                          get_order(elfcorebuf_sz_orig));
                return rc;
        }
        set_vmcore_list_offsets_elf32(elfcorebuf, &vmcore_list);
@@ -780,7 +791,8 @@ void vmcore_cleanup(void)
                list_del(&m->list);
                kfree(m);
        }
-       kfree(elfcorebuf);
+       free_pages((unsigned long)elfcorebuf,
+                  get_order(elfcorebuf_sz_orig));
        elfcorebuf = NULL;
 }
 EXPORT_SYMBOL_GPL(vmcore_cleanup);