From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wu Fengguang Subject: [PATCH 3/3] HWPOISON: prevent /dev/kmem users from accessing hwpoison pages Date: Wed, 16 Sep 2009 09:39:42 +0800 Message-ID: <20090916014958.969524517@intel.com> References: <20090916013939.656308742@intel.com> Return-path: Received: from kanga.kvack.org ([205.233.56.17]) by lo.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1Ov8D2-0003br-3E for glkm-linux-mm-2@m.gmane.org; Mon, 13 Sep 2010 14:32:32 +0200 Received: from mail137.messagelabs.com (mail137.messagelabs.com [216.82.249.19]) by kanga.kvack.org (Postfix) with SMTP id 409276B011B for ; Mon, 13 Sep 2010 08:31:46 -0400 (EDT) Content-Disposition: inline; filename=kmem-dev-kmem.patch Sender: owner-linux-mm@kvack.org To: Andrew Morton , KAMEZAWA Hiroyuki Cc: Benjamin Herrenschmidt , Greg KH , Andi Kleen , Christoph Lameter , Ingo Molnar , Tejun Heo , Nick Piggin , Wu Fengguang , LKML , linux-mm@kvack.org List-Id: linux-mm.kvack.org 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 CC: Andi Kleen CC: Benjamin Herrenschmidt CC: Christoph Lameter CC: Ingo Molnar CC: Tejun Heo CC: Nick Piggin Reviewed-by: KAMEZAWA Hiroyuki Signed-off-by: Wu Fengguang --- 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; } -- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org