Messages in this thread Patch in this message | | | Date | Thu, 4 Feb 2010 10:43:54 +0800 | From | Wu Fengguang <> | Subject | [stable] [PATCH] devmem: fix kmem write bug on memory holes |
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From: Wu Fengguang <fengguang.wu@intel.com>
commit c85e9a97c4102ce2e83112da850d838cfab5ab13 upstream.
write_kmem() used to assume vwrite() always return the full buffer length. However now vwrite() could return 0 to indicate memory hole. This creates a bug that "buf" is not advanced accordingly.
Fix it to simply ignore the return value, hence the memory hole.
CC: Andi Kleen <andi@firstfloor.org> CC: Benjamin Herrenschmidt <benh@kernel.crashing.org> CC: Christoph Lameter <cl@linux-foundation.org> CC: Ingo Molnar <mingo@elte.hu> CC: Tejun Heo <tj@kernel.org> CC: Nick Piggin <npiggin@suse.de> CC: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> CC: <stable@kernel.org> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com> --- drivers/char/mem.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- linux-2.6.32.orig/drivers/char/mem.c 2010-02-04 10:37:55.000000000 +0800 +++ linux-2.6.32/drivers/char/mem.c 2010-02-04 10:37:59.000000000 +0800 @@ -599,7 +599,7 @@ static ssize_t write_kmem(struct file * break; } } - len = vwrite(kbuf, (char *)p, len); + vwrite(kbuf, (char *)p, len); count -= len; buf += len; virtr += len;
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