(2013/10/13 5:32), Alexey Dobriyan wrote:
On Wed, Oct 09, 2013 at 07:14:55PM +0900, HATAYAMA Daisuke wrote:
Hello,
(2013/10/08 21:49), Alexey Dobriyan wrote:
On Mon, Oct 7, 2013 at 5:42 AM, HATAYAMA Daisuke
<d.hatay...@jp.fujitsu.com> wrote:
+static unsigned long
+get_unmapped_area_vmcore(struct file *filp, unsigned long addr,
+ unsigned long len, unsigned long pgoff,
+ unsigned long flags)
+{
+#ifdef CONFIG_MMU
+ return current->mm->get_unmapped_area(filp, addr, len, pgoff,
flags);
+#else
+ return -EIO;
+#endif
+}
+
static const struct file_operations proc_vmcore_operations = {
.read = read_vmcore,
.llseek = default_llseek,
.mmap = mmap_vmcore,
+ .get_unmapped_area = get_unmapped_area_vmcore,
I think current->mm->get_unmapped_area should be used by core proc code.
What do you actually suggest here? You mean moving this code in proc code?
I don't think you suggest so.
Please, try this patch, I don't have kexec setup handy.
--- a/fs/proc/inode.c
+++ b/fs/proc/inode.c
@@ -291,7 +291,11 @@ static unsigned long proc_reg_get_unmapped_area(struct
file *file, unsigned long
int rv = -EIO;
unsigned long (*get_unmapped_area)(struct file *, unsigned long,
unsigned long, unsigned long, unsigned long);
if (use_pde(pde)) {
- get_unmapped_area = pde->proc_fops->get_unmapped_area;
+ get_unmapped_area = current->mm->get_unmapped_area;
+#ifdef CONFIG_MMU
+ if (pde->proc_fops->get_unmapped_area)
+ get_unmapped_area = pde->proc_fops->get_unmapped_area;
+#endif
if (get_unmapped_area)
rv = get_unmapped_area(file, orig_addr, len, pgoff,
flags);
unuse_pde(pde);
Slight modification to #ifdef ...
get_unmapped_area = NULL;
#ifdef CONFIG_MMU
get_unmapped_area = current->mm->get_unmapped_area
#endif
if (pde->proc_fops->get_unmapped_area)
get_unmapped_area = pde->proc_fops->get_unmapped_area;
And, I found the bug. The variable rv should have been defined as unsigned
long. sizeof(int) is 4 bytes but sizeof(long) is 8 bytes at least on x86_64.
The reason why returned value looked like kernel virtual address was due to
signed extension performed during conversion from negative 32-bit signed
integer to 64-bit unsigned long integer.
Hmm, I first checked signature of related functions but overlooked...
Anyway, I'll post fixing patch soon.
--
Thanks.
HATAYAMA, Daisuke
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