When /dev/kmem read()/write() encounters hwpoison page, stop it
and return the amount of work done till now.
Vmalloc pages are not checked for now, to avoid conflicts with
ongoing vread/vwrite works.
CC: Greg KH <greg@xxxxxxxxx>
CC: Andi Kleen <andi@xxxxxxxxxxxxxx>
CC: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
CC: Christoph Lameter <cl@xxxxxxxxxxxxxxxxxxxx>
CC: Ingo Molnar <mingo@xxxxxxx>
CC: Tejun Heo <tj@xxxxxxxxxx>
CC: Nick Piggin <npiggin@xxxxxxx>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
Signed-off-by: Wu Fengguang <fengguang.wu@xxxxxxxxx>
---
drivers/char/mem.c | 18 ++++++++++++++----
1 file changed, 14 insertions(+), 4 deletions(-)
--- linux-mm.orig/drivers/char/mem.c 2009-09-16 09:25:34.000000000 +0800
+++ linux-mm/drivers/char/mem.c 2009-09-16 09:25:43.000000000 +0800
@@ -427,6 +427,9 @@ static ssize_t read_kmem(struct file *fi
*/
kbuf = xlate_dev_kmem_ptr((char *)p);
+ if (unlikely(virt_addr_valid(kbuf) &&
+ PageHWPoison(virt_to_page(kbuf))))
+ return -EIO;
if (copy_to_user(buf, kbuf, sz))
return -EFAULT;
buf += sz;
@@ -472,6 +475,7 @@ do_write_kmem(unsigned long p, const cha
{
ssize_t written, sz;
unsigned long copied;
+ int err = 0;
written = 0;
#ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED
@@ -498,13 +502,19 @@ do_write_kmem(unsigned long p, const cha
*/
ptr = xlate_dev_kmem_ptr((char *)p);
+ if (unlikely(virt_addr_valid(ptr) &&
+ PageHWPoison(virt_to_page(ptr)))) {
+ err = -EIO;
+ break;
+ }
+
copied = copy_from_user(ptr, buf, sz);
if (copied) {
written += sz - copied;
- if (written)
- break;
- return -EFAULT;
+ err = -EFAULT;
+ break;
}
+
buf += sz;
p += sz;
count -= sz;
@@ -512,7 +522,7 @@ do_write_kmem(unsigned long p, const cha
}
*ppos += written;
- return written;
+ return written ? written : err;
}
--
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