From c9efe51165fa0aff57be54e3cb0201ac87f68980 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Sun, 2 Feb 2014 07:05:05 -0500 Subject: [PATCH] fix a kmap leak in virtio_console While we are at it, don't do kmap() under kmap_atomic(), *especially* for a page we'd allocated with GFP_KERNEL. It's spelled "page_address", and had that been more than that, we'd have a real trouble - kmap_high() can block, and doing that while holding kmap_atomic() is a Bad Idea(tm). Signed-off-by: Al Viro --- drivers/char/virtio_console.c | 9 +++------ 1 file changed, 3 insertions(+), 6 deletions(-) diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c index feea87c..6928d09 100644 --- a/drivers/char/virtio_console.c +++ b/drivers/char/virtio_console.c @@ -890,12 +890,10 @@ static int pipe_to_sg(struct pipe_inode_info *pipe, struct pipe_buffer *buf, } else { /* Failback to copying a page */ struct page *page = alloc_page(GFP_KERNEL); - char *src = buf->ops->map(pipe, buf, 1); - char *dst; + char *src; if (!page) return -ENOMEM; - dst = kmap(page); offset = sd->pos & ~PAGE_MASK; @@ -903,9 +901,8 @@ static int pipe_to_sg(struct pipe_inode_info *pipe, struct pipe_buffer *buf, if (len + offset > PAGE_SIZE) len = PAGE_SIZE - offset; - memcpy(dst + offset, src + buf->offset, len); - - kunmap(page); + src = buf->ops->map(pipe, buf, 1); + memcpy(page_address(page) + offset, src + buf->offset, len); buf->ops->unmap(pipe, buf, src); sg_set_page(&(sgl->sg[sgl->n]), page, len, offset); -- 2.7.4