On 2020/8/19 00:24, Christoph Hellwig wrote:
I think we should go for something simple like this instead:
This idea is fine to me. Should a warning message be through here? IMHO the driver still sends an improper page in, fix it in silence is too kind or over nice to the buggy driver(s).
And maybe the fix in nvme-tcp driver and do_tcp_sendpages() are still necessary. I am not network expert, this is my opinion for reference.
Coly Li
From 4867e158ee86ebd801b4c267e8f8a4a762a71343 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig hch@lst.de Date: Tue, 18 Aug 2020 18:19:23 +0200 Subject: net: bypass ->sendpage for slab pages
Sending Slab or tail pages into ->sendpage will cause really strange delayed oops. Prevent it right in the networking code instead of requiring drivers to work around the fact.
Signed-off-by: Christoph Hellwig hch@lst.de
net/socket.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/net/socket.c b/net/socket.c index dbbe8ea7d395da..fbc82eb96d18ce 100644 --- a/net/socket.c +++ b/net/socket.c @@ -3638,7 +3638,12 @@ EXPORT_SYMBOL(kernel_getpeername); int kernel_sendpage(struct socket *sock, struct page *page, int offset, size_t size, int flags) {
- if (sock->ops->sendpage)
- /*
* sendpage does manipulates the refcount of the passed in page, which* does not work for Slab pages, or for tails of non-__GFP_COMP* high order pages.*/- if (sock->ops->sendpage && !PageSlab(page) && page_count(page) > 0) return sock->ops->sendpage(sock, page, offset, size, flags);
return sock_no_sendpage(sock, page, offset, size, flags);